MASONRY NC II - CBLM

COMPETENCY-BASED LEARNING MATERIALS
Sector:
CONSTRUCTION SECTOR (CIVIL
WORKS)
Qualification
Title:
MASONRY NC II
Unit of
Competency:
LAY CONCRETE HOLLOW BLOCKS
FOR STRUCTURE
Module Title:
LAYING CONCRETE HOLLOW
BLOCKS FOR STRUCTURE
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Complete Training Center Name and
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HOW TO USE THIS COMPETENCY-BASED LEARNING MATERIAL
MODULE TITLE: LAY CONCRETE HOLLOW BLOCKS FOR STRUCTURE.
This is a Competency-Based Learning Material for the Module: LAYING
CONCRETE HOLLOW BLOCKS FOR STRUCTURE.
This learning material contains activities for you to complete. It covers the
Knowledge, Skills and Attitudes required to complete the competency.
You are required to go through a series of learning activities in order to complete
each of the learning outcomes of this module. In each learning outcome, Learning
Elements and Reference Materials are available for your further reading to assist you
in the required activities. You are expected to accomplish all the required activities
and to answer the self-check after each learning element. Please note that you need
to have 100% correct answers to each self-check to pass the activity. You are
required to obtain answer sheets, which are available from your trainer or at the end
of each learning element, to reflect answers for each self-check. If you have
questions, please do not hesitate to ask your facilitator for assistance.
Recognition of Prior Learning (RPL)
You may have acquired some or most of the knowledge and skills covered in this
learning material because you have:
• Actual experience on the job;
• Already completed training in this area.
BENEFITS OF RPL
• Gives credit for knowledge and experience.
• Reduces duplication of learning.
• Reduces costs of obtaining formal credentials.
• Gives immediate feedback and determines which competencies need
verification and testing.
• Identifies training gaps.
• Training (is individualized and results in a recognized certificate).
• Assists in professional development.
• Allows for better use of time and resources.
• Potentially saves on training costs.
So, if you can demonstrate to your trainer that you are competent in a particular skill,
you do not have to do the same training again. Or, if you feel you have the skills, talk
to your trainer about having them formally recognized. You may also show your
Certificates of Competence from previous training. And if your acquired skills are still
updated / relevant to the module, they may become part of the evidence you can
present for RPL.

A Record of Achievement is also provided for your trainer to fill-in upon completion of
this module.
This module was prepared to help you achieve the required competencies in
Establishing Vertical and Horizontal Guides, Performing Laying of Concrete Hollow
Blocks, Performing Jointing Process. It will serve as a source of information for you
to acquire the required knowledge, skills, attitude, and inherent behaviour for the
UNIT OF COMPETENCY: LAY CONCRETE HOLLOW BLOCKS FOR
STRUCTURE for the MASONRY NC II qualification, with minimum supervision or
help from your trainer. This material will aid you in acquiring the competency at your
own pace, independently. To achieve the full benefit of this module:
• Talk to your trainer and agree on how you will both organize your training on
this unit. Read through the Competency Based Learning Material carefully. It
is divided into sections which cover all the skills and knowledge you need to
successfully complete this module.
• Most probably, your trainer will also be your supervisor. He / She will be there
to support and show you the correct way to do things. Ask for help if you need
one.
• Your trainer will tell you about the important things you need to consider when
doing the activities. It is important you listen and take notes.
• You will have plenty of opportunities to ask questions and undergo rigid
practice. This will help you in achieving competency in your new skill. Ample
practice will improve your speed, memory and confidence.
• Talk with more experienced colleagues and ask for guidance.
• Answer self-checks at the end of each section to test your own progress.
• When you finished each element and feel that you are ready, demonstrate the
activities outlined in the learning material to your trainer.
• As your work through the activities, your trainer will be taking note of your
performance. He / She will be providing feedback on your progress. Your
readiness for assessment will be reflected in his/her report, if and when you
have successfully completed each element.

INTRODUCTION TO THE MODULE
UNIT OF COMPETENCY : LAY CONCRETE HOLLOW BLOCKS FOR
STRUCTURE
MODULE TITLE : LAYING CONCRETE HOLLOW BLOCKS FOR
STRUCTURE
MODULE DESCRIPTOR : This module covers the knowledge, skills and attitude
required in productively establishing vertical and
horizontal guides, laying concrete hollow block and
performing jointing process.
Introduction:
This module contains information and learning activities in Laying Concrete Hollow
Blocks for Structure.
Upon completion of this module and you feel confident that you have had sufficient
practice, you may request your Trainer to arrange an appointment with a registered
Assessor for your assessment. The results of the assessment will be recorded in
your Competency Achievement Record.
SUMMARY OF LEARNING OUTCOMES:
At the end of this Competency-Based Learning Material, the learners are expected to
meet the following learning outcomes:
LO 1. Establish a Vertical and Horizontal Guides
LO 2. Perform Laying of Concrete Hollow Blocks
LO 3. Perform Jointing Process
ASSESSMENT CRITERIA
Critical Aspects of Assessment
Evidence of the following is critical:
LO 1. Establish a Vertical and Horizontal Guides:
1.1 Personal Protective Equipment (PPE) is used in accordance with Rule 1080 of
Occupational Safety and Health Standards.
1.2 Drawings and specifications are read and interpreted.
1.3 Materials, tools and equipment are selected and prepared consistent with the
job requirements.
1.4 Location of concrete hollow block wall is established based on reference
building/wall lines.
1.5 Horizontal / vertical guide for hollow block is installed and marked according to
specifications.
1.6 Work area is cleaned according to safety and environmental regulations (e.g.
PD 1152 Section 6, 8 & 42).
1.7 Required output is completed as specified by the immediate supervisor based
on work schedule.

LO 2. Perform Laying of Concrete Hollow Blocks:
2.2 Reinforcing bar / dowel are installed according to required job specifications.
2.3 Mortars are spread on the base /edge of hollow block according to job
specifications.
2.4 Hollow block is laid on the line according to job specifications.
2.5 Constant checking of plumbness and alignment is done during hollow block
laying.
2.6 Excess mortars on joints are scraped.
PD 1152 Section 6, 8 & 42);
on work schedule.
LO 3. Perform Jointing Process:
3.2 Jointing is done in accordance with job specifications.
3.3 Finishing touches is done according to job specifications.
PD 1152 Section 6, 8 & 42).
on work schedule.
Resources Implications:
Resource Implications must ensure that:
• This competency is to be assessed using standard and authorized work
practices, safety requirements and environmental constraints.
• This unit of competency could be assessed in an off-site context, in the
workplace or a close simulation of the workplace environment, provided that
simulated or project-based assessment techniques fully replicate construction
workplace conditions, materials, activities, responsibilities and procedures.
Assessment Methods:
The following methods may be used to assess competency for this module:
• Demonstration / Observation with oral questioning.
• Observation of practical candidate performance.
• Simulated practical exercises.
• Role plays.
• Oral and written questions.

Program/ Course : MASONRY NC II
Unit of Competency : Lay Concrete Hollow Blocks for Structure
Module : Laying Concrete Hollow Blocks for Structure
Learning Outcome No. 1: Establish a Vertical and Horizontal Guides
Assessment Criteria:
1.1 Personal protective equipment (PPE) is used in accordance with Rule 1080 of
1.2 Drawings and specifications are read and interpreted.
1.3 Materials, tools and equipment are selected and prepared consistent with the
job requirements.
1.4 Location of concrete hollow block wall is established based on reference
building/wall lines.
1.5 Horizontal / vertical guide for hollow block is installed and marked according to
specifications.
PD 1152 Section 6, 8 & 42).
on work schedule.
References:
• Carlevaro, Nadia, Roux-Fouillet, Guillaume, Schacher, Tom. How to Build
Safer Houses with Confined Masonry 2018. Practical Action Publishing, Ltd.
• Provey, Joe, Ross, John, Editors. Tauton’s Masonry Complete 2012. The
Tauton Press, Inc.
• Black & Decker. The Complete guide to Masonry & Stonework New 3rd
Edition
2010. Creative Publishing International, Inc.
• Zilch, Conrad, Schatz, Martin. Masonry Construction Manual 2001. Institut fur
internationale Architektur-Dokumentation GmbH, Munich.
• Beall, Christine. Complete Construction – Masonry and Concrete for
Residential Construction 2004. McGraw-Hill Publisher, Inc.
• The U. S. Department of Housing and Urban Development. Building Concrete
Masonry Homes, Design Construction Issues, 1998. NAHB Research Center,
Inc.
• Field Manual No. 5-428 Concrete and Masonry 1998. Headquarters
Department of the Army.
• Curtin, W.G., Shaw, G., Beck, J. K., Bray, W.A. Structural Masonry Designer’s
Manual 2nd
Edition (Revised) 1995. Blackwell Science, Ltd.
• Websites:
o https://liferayprod.cemex.com/web/guest
o https://www.constructionknowledge.net/construction_knowledge.php
o https://bessconcreteblockmachine.com/what-is-hollow-block.html
o https://contractorsinsurance.org/masonry-contractors-safety-tips/
o https://www.ilo.org/wcmsp5/groups/public/---ed_emp/---
emp_ent/documents/instructionalmaterial/wcms_650136.pdf

INFORMATION SHEET NO.: 1 / UC NO.: 1
ESTABLISH A VERTICAL AND HORIZONTAL GUIDES
Introduction
Masonry is the structural construction of
component parts laid in and bound together by a
material called mortar. These individual
materials which are introduced in any structure
for various purposes and patterns may be tile,
brick, granite, limestone, glass and concrete
block, stucco, marble, stone, and travertine.
The production of masonry units should generally conform to the requirements in the
2003 International Building Code (IBC) Section 2103. Aside from mortar, assembling
these units can be reinforced appropriately by steel (rebar) that offers much strength
to structures.
Recommended Safety Precautions for Masonry Workers
Masonry is also an integral part of the construction of both commercial and
residential structures. Although the process has several major advantages, the work
can be very labor intensive. Masonry workers may risk illness and injury as they
work on homes, buildings, bridges and public works projects. Over the years,
experienced masons have learned how to stay safe in dangerous conditions by
following a list of recommended safety precautions.
Common Ways Masonry Workers get Injured
Masons use bricks, concrete blocks, concrete and natural and man-made stones to
build walls, walkways, fences and other structures. As they build with these heavy
substances, workers may deal with dangerous conditions, like exposure to
chemicals.
In fact, masonry workers have a higher rate of injuries and illnesses than the national
average, according to the Bureau of Labor Statistics.
The most common masonry injuries are:
• Slips, trips and falls.
• Falling objects.
• Collapsing or cave-in of excavations or
walls.
• Sharp or protruding objects.
• Exposure to noxious chemicals.
• Moving, lifting or carrying heavy objects
• Overexposure to dust
Many of these injuries can result in Workers Compensation Insurance claims, which
can cost employers in increased insurance rates and lost productivity.

Safety Precautions Every Mason Worker Should Follow
Despite the dangers of the job, masonry workers can stay safe if they take safety
precautions. Experienced masons take the preventative actions outlined in these
eight tips on a daily basis:
1. Avoid all contact with unhardened masonry cement.
2. Always use proper Personal Protective Equipments (PPE’s).
3. Wear impervious clothing and gloves to eliminate the possibility of skin
contact.
4. Always double-check the safety of portable electric tools.
5. Install sturdy work surfaces.
6. Wear sturdy safety shoes with anti-skid soles.
7. Wash hands thoroughly at the end of every work shift.
8. Use respiratory protection equipment, like air masks and respirators.
These safety precautions are easy for both
employers and employees to follow. With simple
changes in work behavior, like being more
prepared, masons can significantly cut down on
the risk of injury and illness.
From brick masons to cement masons to stone
masons, daily safety checks are a crucial part
of a workplace safety program.
Employees who learn to follow recommended work guidelines become more
valuable assets to their employers, which can help solidify the success of a
contracting company.
Accurate Setting Out
Accurate setting out is a fundamental part of
the construction works, and errors can be very
expensive and time consuming to correct. It
should only be undertaken by competent
persons, and all work should be thoroughly
checked, preferably by different personnel.
Setting out is usually undertaken once the site has been subject to a condition
survey and desk study, and has been cleared of any debris, unwanted vegetation
or obstructions. Works necessary to create required levels may also have
been completed before the layout process begins. The position and orientation of
the structure is generally described in architects’ or engineer’s drawings and defining
precisely how the layout should be arranged.
Controlling dimensions and references on the plans will determine the positioning of
the building and in particular its foundations. These include; overall length and width,
the distances to road center-lines and to other structures situated on the site, and
other internal structural measurements, approaches and rights-of-way and so on.

The controlling points of the structure can then be marked so that the construction
team is able to easily identify them. This usually consists of marking
the building’s corners, horizontal and vertical positions, using stakes, and batter
boards with string lines, drill holes, cut-and-fill notations, and other methods.
Temporary Bench Mark (TBM)
A Temporary Bench Mark is a fixed
point with a known elevation, usually
at a ground floor level. Establishing it
should be undertaken at an early
stage. It is the fixed point which kicks-
off the setting out and to which
all levels are related. Where possible
the TBM should relate to an ordnance
bench mark. On the site, it could
relate to any permanent fixture, such
as a manhole cover or firmly-driven post. Typically, it is signified by a peg
or steel angle that is conveniently located (e.g. near the site office) and concreted in
or fenced off with low-level timberwork.
As minus signs are easily misread, the TBM position should enable all other levels to
be positive. The TBM should be clearly indicated on all drawings, with all levels and
vertical dimensions expressed in meters to three decimal places in relation to it.
Baseline
Typically the first layout task is establishing a baseline to which all the setting out can
be related. The baseline is a straight reference line in respect to which
the building’s corners are located on the ground. It often coincides with the ‘building
line’, which is the boundary of the area, or the outer boundary of a road or curb, often
demarcated by the local authority.
Horizontal Controls
These are the points that have known coordinates with respect to a specific point.
Other points such as layout corners can then be located. Numerous
control points should be used so that each point of the plan can be precisely located
on the ground.
Vertical Controls
These enable design points to be positioned at their correct levels. The vertical
control points are established relative to specified vertical datum – often
a timber post set in concrete. But it can also be a specific height from a
nearby road or land feature.
Horizontal and vertical controls are generally established during the leveling phase
using a theodolite or similar instrument.
Levels on site-layout plans should be denoted in meters to three decimal places, e.g.
32.350. Also, intended levels should be written in a box, while existing levels can be
written normally. An 'x' or '+' should be used on plans to denote the exact point to
which a level applies.

Building Layout
For a simple building layout, such as a rectangle, the outline of the building is
marked by a line tied to corner posts - a nail in the top of the post can be used to
attach the line to. A theodolite, site square or builder’s square is used to turn off 90-
degree angles for the remaining corners. Ranging rods may be required to establish
a straight line between corner posts.
Corner posts are usually 50 x 50mm timber posts driven firmly into the ground, with
a nail in the post’s centre. The outline may be marked on the ground with dry lime or
similar powder. Timber profile boards can be used at the corners. Profile boards are
typically between 0.6-1m in height and comprise two 50 x 50mm posts driven at least
600mm into the ground, with a 150 x 38mm cross board.
Where the outline of a building is more complex than a simple rectangle, it may be
necessary to establish a range of points in the same way as for laying out a simple
rectangle. However, great care is
required, as small errors are more likely to
be introduced as more points are
positioned. Often the easiest way of laying
out an irregular building shape is to first
lay out a large rectangle which will
enclose the entire building or the greater
part of it. Once this is done, deductions
and alterations can be made to obtain
the precise layout required.
Trenches
The layout of trenches establishes the excavation size, shape and direction, as well
as the width and position of walls. Trenches are excavated once the building outline
has been set out. The width is often marked with a line of dots of dry lime powder
for accurate excavation by hand by, whereas the centre line is marked for accurate
machine or manual excavation.
Outline profile boards are often used to control trench positioning, width and depth.
In order that they do not obstruct the excavation work, profile boards should be set
up at least 2m clear of the trench positions. The level of the profile cross board
should be related to the site datum and fixed at a convenient height above ground
level, often with cords strung between two profiles at either end of the trench. Bands
can be painted on the cross board for identification purposes.
Pegs are often driven into the bottom of the trench to mark the top of
the concrete strip that is subsequently poured.
The corners of walls are transferred from intersecting cord lines to mortar spots on
the concrete foundations, using a spirit level for accuracy.
The cutting of trenches needs to be undertaken with great care, especially if they are
to be left open for an extended period as there is the possibility of the sides caving
in.

Reduced Level Excavations
The overall outline of a reduced level area
can be set out working form a baseline.
Corner posts are fixed to the outline of
the excavation area and the outline
marked with dry sand or similar material.
To control the depth of the excavation,
sight rails are set up at a
convenient height and at positions which
will enable a traveler to be used.
A traveler is a profile boards with a fixed
height, used for controlling excavated
levels between profile boards.
By placing the traveler in the sightline between two level boards, it is possible to see
whether or not the excavation has been carried out to correct levels. The height of
the traveler is the desired level of the sight rail minus the formation level of the
excavated area.
Framed Building
Framed buildings are usually related to a grid, often set out from a baseline. The
intersections of the grid lines mark the centre points for isolated or pad foundations.
The layout of the grid is established using a theodolite and the grid intersections
marked using pegs. Once the grid has been set out, offset pegs or profiles can be
fixed clear of any subsequent excavation work. Control of excavation depth can be
by means of a traveler sighted between sight rails or by level and staff related to
a site datum.

SELF-CHECK NO.: 1 / UC NO.: 1
ESTABLISH A VERTICAL AND HORIZONTAL GUIDES
Instruction: Choose the correct answer and encircle the letter of your choice.
1. A fixed point with a known elevation, usually ground floor level.
A. Temporary Bench Mark.
B. Fixed Bench Mark.
C. Standard Bench Mark.
D. Elevation Bench Mark.
2. This is a crucial part of a workplace safety program.
A. Standard Safety Checks.
B. Daily Safety Checks.
C. Duty Safety Checks.
D. Company Safety Checks.
3. This is a fundamental part of the construction works, and errors can be very
expensive and time consuming to correct.
A. Dimension Setting.
B. Elevation Setting.
C. Accurate Setting.
D. Mason’s Setting.
4. __________ and references on the plans will determine the positioning of
the building and in particular its foundations.
A. Additional Dimensions.
B. Controlling Dimensions.
C. Elevated Dimensions.
D. Structured Dimensions.
5. This is the structural construction of component parts laid in and bound together
by a material called mortar.
A. Cement.
B. Groundwork.
C. Sluice.
D. Masonry.

ANSWER KEY NO.: 1 / UC NO.: 1
REMOVE HAIR AND HOOVES
1. A. Temporary Bench Mark.
2. B. Daily Safety Checks.
3. C. Accurate Settings.
4. B. Controlling Dimensions.
5. D. Masonry.

Learning Outcome No. 2: Perform Laying of Concrete Hollow Blocks
2.2 Reinforcing bar / dowel are installed according to required job specifications.
2.3 Mortars are spread on the base / edge of hollow block according to job
specifications.
2.4 Hollow block is laid on the line according to job specifications.
2.5 Constant checking of plumbness and alignment is done during hollow block
laying.
2.6 Excess mortars on joints are scraped.
PD 1152 Section 6, 8 & 42);
on work schedule.
References:
Tauton Press, Inc.
• Black & Decker. The Complete guide to Masonry & Stonework New 3rd
Edition
Inc.
Manual 2nd
• Websites:
o https://www.sheltercluster.org/sites/default/files/docs/Key%20Message
s%20CHB%20V1.1.pdf
o https://www.wikihow.com/Lay-Concrete-Blocks
o https://archiandesigns.wordpress.com/2015/07/29/masonry-concrete-
hollow-block-laying/
o https://www.bhg.com/home-improvement/outdoor/retaining-walls/how-
to-lay-concrete-block/
o https://medium.com/@buboyvirata/chb-laying-all-you-need-to-know-
within-15-minutes-part-1-50e3642271c8

o https://www.huduser.gov/portal/publications/PDF/masonry.pdf
o https://www.bhg.com/home-improvement/patio/installation-how-to/tips-
for-working-with-concrete-block/

INFORMATION SHEET NO.: 2 / UC NO.: 1
PERFORM LAYING OF CONCRETE HOLLOW BLOCKS
Introduction
Concrete Hollow Blocks (CHB), are one of the most extensively used walling
materials locally. Some of the reasons for this are their relative low cost when
compared to other materials and speed of installation by semi-skilled labourers or
masons. CHB walls are very weak against lateral loads (pushing or pulling forces
from typhoon or earthquake). Adding steel reinforcing bars vertically and horizontally
inside the CHBs can increase their resistance to lateral loads.
What is a Hollow Block?
In general, Hollow Block is a type of concrete
block used for building internal and external
walls. Hollow concrete block saves time in
building walls due to its large dimensions.
Due to the load-carrying capacity; the hollow
block is playing an important role in the
construction industry.
Hollow blocks are made using molds and a suitable additive depending on your
location and your project. It is believed that concrete blocks are one of the most
popular construction materials which are used in the construction industry almost
everywhere. Cement is used to bond components in order to produce stronger and
longer life hollow blocks.
Hollow Block Composition
As an additive any of the below materials can be used:
1. Volcanic ash.
2. Granite rubble.
3. Sand.
4. Broken glass, brick, concrete, hardened cement.
5. Expanded clay.
6. River gravel; or crushed stone.
7. Sawdust. Some combustion products: boiler slag, ash.
Concrete Block Types and Description
Concrete block is considered as inexpensive material, therefore, used by builders
quite often.
Regarding the properties and appearance of concrete blocks, they are presented in
the following varieties:
Solid Concrete Block:
Solid concrete blocks are used for laying the
foundation, columns, supporting structures of
buildings, and basements. The leading role is
played by their durability.

Hollow Blocks
Concrete hollow block with emptiness inside is used
as a building material in the construction of walls
and partitions of a building. They are lighter, so they
do not add to the total weight of the structure too
much. Usually, these hollow blocks are produced in
a way to interlock each other and the machine that
produces these blocks are called an interlocking
brick machine, so don't get confused if you hear
this name.
Decorative Facing Concrete Hollow Block:
Appeared on the building materials market not so long ago.
Their distinctive feature is the presence of a decorative
coating on one or two sides.
This layer of the concrete hollow block not only duplicates
various textures (stone, plaster) but also performs a
protective function - makes it resistant to moisture.
Due to this, there is no need for
complex finishing work.
Partition Concrete Hollow Block:
They are used in the laying of partitions and have some
advantages: accurate wall geometry is observed, solution
saving, low weight compared to brick, and quick installation.
These blocks are produced in both hollow and solid types.
Choosing the right type depends on your project.
Colored Concrete Hollow Block:
Used in construction as conventional materials, hollow blocks
are most often used in the construction of fences, gables,
decorative pillars. They achieve the desired shade already at
the stage of the hollow block manufacturing process. To do this,
crushed red brick or colored chalk is added to the mixture.
Base Concrete Hollow Block:
Their other name is an artificial wall stone. It
differs in durability and durability in use, does
not shrink, and does not crumble. A
prerequisite for laying the foundation of
concrete hollow blocks is the presence of
reinforced concrete tape, which must have a
layer of at least 1.5 centimeters. The walls of
the foundation blocks are necessarily
covered with hydro and heat insulation.

Rough Surface Hollow Concrete Block:
This building material has a decorative surface under the
"ragged" and crushed concrete hollow block. It is used most
often as a cladding for fences and decoration of buildings or
structures.
Hollow Block Dimensions and Standards
The hollow block is also known as a hollow cement block or hollow concrete
block as well. It is sometimes called a concrete masonry unit as well. The shapes
and sizes of most of the common concrete blocks have been standardized to ensure
uniform building construction. Hollow block machines are also manufactured with
the same standard. The machine has the feature of working for 24 hours. It has
different Automation levels and capacities. The machine is very fast and has a high
production capacity. Except for product drying and curing rooms, there is no extra
equipment needed in the plant. Bess designs different options, manual hollow block
machine, Semi-Automatic concrete block machine, and fully automatic block
making machine.
Normally the size of a standard hollow
block is 20cm x (width) x 40cm (length) x
20 cm (height) this is a worldwide
standard and the manufacturers produce
their hollow blocks considering this
standard. There are also other standards
but this is the standard that the machine
capacity is calculated with.
Hollow Block Advantages
Hollow blocks are important masonry units in construction. Here I am sharing some
advantages of using the hollow block in buildings and construction:
1. Rapid Execution of Work in Construction.
Hollow cement blocks are produced by the hollow block machine also
known as the concrete block machine in different shapes, sizes, and
weights. It is easy to deploy hollow blocks in construction works, all that is
needed is to fit the right block to the right place. Using the same shape and
sizes helps to easily assemble them to form any particular shape that is
required in the construction area.
2. Extremely Durable.
The hollow block produced by high pressure and vibration make the blocks
very strong, resilient hardened to severe load, and weight.
3. Better Insulation.
As hollow blocks have holes and because of the air in the hole of the block, it
does not allow heat or cold in or out of the building. Hollow blocks are
insulated against heat, wetness, and sound. Hollow blocks keep the house
cool in summer and warm in winter.
4. Environmentally Friendly.
It does not infect or have any known environment frustration it constitutes to
the system.

5. Cost-Efficient.
Hollow block helps in reducing construction materials used at a construction
site, though reducing the cost of construction
6. Low Maintenance.
Maintenance of hollow block structures is not expensive, compared to
other construction materials that are available in the market.
7. Reduce Consuming Space.
The construction of thin walls with hollow blocks is very common. So, it helps
to reduce the space used in construction and increases the floor area.
8. Bonding of Mortar and Plaster
As the surfaces of hollow blocks are rough, this provides a good bonding
between mortar and plaster.
Hollow Block Disadvantages
There is nothing in the whole world that has only advantages and not one single
disadvantage, let's talk about the possible disadvantages of the hollow block:
1. Appearance:
Unfortunately, many people still have the impression that a hollow block is
unsightly and utilitarian, but technology has advanced significantly and now these
hollow blocks can be treated with various render products and techniques,
allowing you to create impressive finishes that look a lot more expensive than
they actually are.
Even different colors are added to the mortar these days to produce different
colors of blocks. This way you can have the exact color of the hollow concrete
blocks you have in mind for the facing of your building and interior walls as well.
2. Water Absorption:
Another problem with the hollow block
is its ability to absorb water. We are
all familiar with the expansion strength
of water when it freezes, so we can
understand that a retaining wall, one
that is in constant contact with the
earth behind it, would be wet most of
the time.

This cannot be said for the wall of a building that is protected from the rain on the
outside and is open to the air on the inside. When the temperature goes below
freezing for a long period of time, it freezes the ground; it will also freeze the
water in the hollow block supporting your retaining wall. Though it may take a few
years, depending on the number of freezes you have each year, eventually,
cracks will begin to form in both the hollow block and the mortar used to hold
them together.
Guide to Laying Bricks and Blocks
Over recent years there has been a lot of talk about the growth of alternative
construction methods.
However, bricks and mortar continue to be the method of choice for most builders.
With this in mind we have gone back to basics with some tips on how to ensure your
walls are built to last and highlighted some examples of when things go wrong.
Construction of Walls
• Set out walls using securely marked profiles with reference lines and datum
levels.
• Wall lengths should be checked for squareness.
• Cross check against diagonal measurements from the Architect’s plans.
• The position of openings must be anticipated to ensure correct and even
bonding occurs: both horizontally and vertically.
• Avoid overstressing mortar by building rises of no more than 1.5m per day.
• Both leaves of a cavity wall should be built at the same time to avoid incorrect
coursing and potential. weakening of an individual leaf (if left unsupported for
any length of time).
Laying Bricks and Blocks
Follow this best practice guide for laying bricks and blocks to ensure your walls
comply with our technical standards:
• Bricks and blocks should be laid level (use the table below as a guide).
• Use a regular bond with a nominal 10mm horizontal bed joint (unless
otherwise specified by the designer).
• Fill cross joints.
• Perpends should be kept vertically aligned as the work proceeds.
• Lay “frog” bricks with the frog uppermost, which then must be filled with
mortar to ensure the wall is stronger and more resistant to sound
transmission.
• Lay hollow blocks on shell bedding with the vertical joints filled.
• Ensure a consistent bond, especially at corners.
• Set each wall tie a minimum of 50mm into both masonry leaves.
• Keep the cavity and insulation clear of any mortar droppings.
Guide for Horizontal and Vertical Alignment of Masonry Walls
The dimensions in the table below represent the level that can be reasonably
achieved for general brick and block work masonry.

Dimension Permissible Deviation
Straightness in any 5m length + / - 10 mm
Verticality up to 2.5 m height + / - 10 mm
Verticality up to 7 m height + / - 20 mm
How Not to Vertically Align Your Wall
The vertical alignment of the load bearing inner leaf of block
work exceeds the above recommendations.
What’s wrong with the picture below?
1. The bonding is inconsistent causing vertical joints to coincide on consecutive
courses.
2. The correct length and type of wall ties have not been used to ensure they are
properly bedded into each leaf of masonry.
Typical Applications of Concrete Hollow Blocks (CHB)
• As non-load-bearing infill between reinforced
concrete columns and beams (frames). Often,
CHBs are installed between reinforced concrete
columns up to the window sill level, and then
lightweight walling materials such as timber
framing cladded with amakan, plywood or
bamboo are installed above.
• As load-bearing infill between reinforced
concrete columns and beams in confined masonry buildings. The CHBs are
reinforced with vertical and horizontal steel bars connected to the reinforced
concrete columns and beams, increasing their resistance to lateral loads.
• As load bearing reinforced CHB in reinforced masonry buildings. The CHBs
are reinforced with vertical and horizontal steel bars increasing their
resistance to lateral loads.

Proportion of Concrete for the Manufacture of CHB’s
This is done in two
different ways:
By weight or volume. The most common method is by
volume (e.g. using a bucket)
Mixture
For CHBs: Mix Proportion 1:7, as per structural engineer’s
specification.
Water
Clean water should be used. Shall not exceed 28 litres per
40 kilograms per bag of cement, slump test (as per ASTM
C-143) shall not exceed 10cm, unless specified by a
structural engineer.
Common CHB Mix
½ bucket water 1 bucket cement 7 buckets sand
Common Mortar Mix
1 bucket water 1 bucket cement 3 buckets sand
Mixing Time
If batch mixer is used, use accurate timing and measuring
devices to operate as per manufacturer’s instructions.
Revolutions should be between 14 and 20 per minute.
Curing
After being removed from the mould, the CHBs should be
covered with a plastic sheet or tarpaulin and kept damp
and shaded for at least 7 days in order to effectively cure.
This can be achieved by continually spraying them with
water or keeping them under water in tanks. A good curing
process leads to less cracking and a stronger, harder,
denser and more durable concrete.
CHB Tips
✓ Selection of raw materials for the manufacture of CHBs: It is recommended
to use good quality, clean ingredients. Avoid using beach sand as it contains
salt which significantly compromises the quality of concrete.
✓ Proportions of materials in mixture: Mix concrete well, using the proportions
specified by a structural engineer. Ensure that an adequate amount of cement
is added and avoid adding excessive water as it weakens the mixture.
Concrete should stand up when mixed, not flow away due to excessive
water.
✓ Mixing: Use a mixing board otherwise water used for mixing will percolate into
the ground and impurities such as dirt and grass could become incorporated
into the mixture. If concrete is mixed in batches, maintain consistent
proportions for all batches.

✓ Pouring and compaction: Ensure the formwork is clean before pouring and
vibrate uniformly. The concrete should be well compacted in order to make
sure that any air which is trapped in the concrete (weak points) is removed.
✓ Curing: Avoid using freshly made, uncured CHBs as they are still in a state of
shrinkage.
✓ Storage: Store CHBs for at least 14 days after curing before using them.
Protect them from rain and ground water, stacking them in a way which allows
air to circulate around and between them.
✓ Transportation: Minimize excessive handling and transportation of CHBs to
avoid damage.
✓ Selection and quality control of CHBs: It is recommended to test the
compressive strength of CHBs produced/purchased in order to ensure they
meet the required strength. Select only strong CHBs.
Blocks with cracks and corners crumbling away when handled; suggests poor
quality. If the CHB breaks when dropped from head height, don’t use it or other
blocks in the same batch.
✓ Construction: Dampen CHBs before laying as dry masonry absorbs water
from the cement, weakening the joint. CHBs should always be laid on a full bed
of mortar and vertical joints should always be filled.
✓ Earthquake and typhoon resistance: In order to increase the building’s
resistance against lateral loads (pushing or pulling forces from typhoon or
earthquake), connect CHB walls to the reinforced concrete columns and
beams with vertical and horizontal steel reinforcing bars, in accordance with
structural engineer’s details.
✓ Maintenance: Consider plastering/rendering the surface of CHB walls in order
to avoid excess absorption of moisture into the wall and to facilitate periodic
cleaning.
HOW TO LAY CONCRETE BLOCK
Once you understand the basics of laying concrete block, the possibilities for walls,
grill houses, and other structures are endless. Get started by planning and snapping
chalk lines. Then, spread mortar, place the blocks, and check for level. This module
explains how to lay concrete block in just six steps.
What You Need:
• Hard Hat.
• Safety Goggles.
• Ear Protection.
• Work Gloves.
• Safety Shoes.
• Mortar.
• Trowel.
• Concrete Blocks.
• Story Pole.
• Level.

Step 1: Start First Course.
Start first course by laying a mortar bed on the footing. Make it 1 to 1-½ inches thick
and about three blocks long.
Step 2: Push In the Corner Block.
Carefully push the corner block into the mortar bed, lining it up with the ends of the
chalk lines on the footing.
Step 3: Check Height.
Check the height of the block with your story pole, and push the block down until the
top is even with the mark. If the block is low, pull it out, place more mortar on the
bed, and replace the block. Then place a level on top of the block and level it along
its length and width.

Step 4: Prep the Second Block.
To prepare the second block, set it on end and butter its ears with a downward
swiping motion of the trowel. Then press down on the mortar; on the inside edge of
the ear. This will keep the mortar from falling off when you set the block. If the mortar
does fall off, start over with fresh mortar.
Step 5: Set Second Block.
Set the second block in place, pushing it against the first block, making sure you
leave a ⅜-inch joint space. Using the same techniques, butter the third block and set
it. Don't remove the excess mortar on the footing until it has set up a bit.
Step 6: Tap and Continue Building.
With three blocks laid, set a level on top and tap the blocks into place with the end of
the trowel handle. Repeat the process on the width of the block. Check for plumb by
holding the level against the side of each block. Then build the other corner and the
leads.

How to Cut a Concrete Block
Concrete block is made in so many configurations that
you may not need to cut it at all. But if you do need to
cut a block, place the block on sand or loose soil and
use a brick set and small sledgehammer to score both
sides of the block. Then set the block with its web up
and place the brick set on the scored line. Strike the
brick set until the block breaks cleanly. Wear eye and
ear protection. You can also cut block with a circular
saw equipped with a masonry blade. Wear eye and ear
protection.
How to Reinforce the Concrete Block
Retaining walls and other walls subject to substantial lateral pressure (sideways
pressure pushing against the face of the wall) require reinforcement. Embed
reinforcing wire in the mortar of every other course, overlapping the ends by at least
6 inches. At a corner, cut and bend the wire 90 degrees.
To tie intersecting walls together, bend rebar into an S shape and embed it into the
mortar as shown.
How to Tie Walls Together.
Walls built perpendicular to each other must be tied together, and if you're putting up
a new wall next to one that's there already, you can't place metal ties between the
courses. Knock a hole in the core of the existing wall, stuff newspaper into the
cavities, and place an S-shape piece of rebar in the hole. Then fill the holes with
mortar and lay the next course.

1. This is a common CHB Mix.
A. ½ Bucket Water, 1 Bucket Cement, 7 Buckets Sand.
B. 1 Bucket Water, ½ Bucket Cement, 5 Buckets Sand.
C. ½ Bucket Water, ½ Bucket Cement. 4 Buckets Sand.
D. ½ Bucket Water, 1 Bucket Cement, 5 Bucket Sand.
2. These are used for laying the foundation, columns, supporting structures of
buildings, and basements.
A. Spatial Concrete Blocks
B. Composite Concrete Blocks.
C. Standard Column Blocks.
D. Solid Concrete Blocks.
3. This is the First Course in laying a mortar bed.
A. Setting.
B. Footing.
C. Routing.
D. Tying.
4. These are one of the most extensively used walling materials locally.
A. Concrete Hollow Blocks.
B. Standard Hollow Blocks.
C. Standard Concrete Blocks.
D. Composite Hollow Blocks.
5. _________ and other walls subject to substantial lateral pressure (sideways
pressure pushing against the face of the wall) require reinforcement.
A. Retaining Floors.
B. Retaining Walls.
C. Retaining Frames.
D. Retaining Corners.

1. A. ½ Bucket Water, 1 Bucket Cement, 7 Buckets Sand.
2. D. Solid Concrete Blocks.
3. B. Footing.
4. A. CHB
5. B. Retaining Walls.

Learning Outcome No. 3: Perform Jointing Process
3.2 Jointing is done in accordance with job specifications.
3.3 Finishing touches is done according to job specifications.
PD 1152 Section 6, 8 & 42).
on work schedule.
References:
Tauton Press, Inc.
• Black & Decker. The Complete guide to Masonry & Stonework New 3rd Edition
Inc.
Manual 2nd
• Websites:
o https://ncma.org/resource/concrete-masonry-construction/
o https://www.concretenetwork.com/concrete/concrete_tools/groovers.ht
m
o https://www.cement.org/learn/concrete-technology/concrete-
construction/contraction-control-joints-in-concrete-flatwork
o https://ncma.org/resource/control-joints-for-concrete-masonry-
empirical-method/
o https://theconstructor.org/practical-guide/concrete-wall-
construction/25959/
o https://theconstructor.org/concrete/joints-in-concrete-structures/970/
o https://www.concretenetwork.com/concrete-joints/

INFORMATION SHEET NO.: 3 / UC NO. 1
PERFORM JOINTING PROCESS
Introduction
Volume changes caused by changes in moisture and
temperature should be accounted for in the design of
reinforced concrete buildings. The magnitude of the
forces developed and the amount of movement
caused by these volume changes is directly related to
building length. Contraction and expansion joints limit
the magnitude of forces and movements and cracking
induced by moisture or temperature change by dividing
buildings into individual segments. Joints can be
planes of weakness to control the location of cracks
(contraction joints), or lines of total separation
between segments (expansion joints).
Although widely used, rules of thumb have the drawback that they do not account for
the many variables which control volume changes in reinforced concrete buildings.
For example, variables which affect the amount of thermally induced movement
include the percentage of reinforcement, which limits the amount of movement and
cracking in the concrete; the restraint provided at the foundation, which limits the
movement of the lower stories; the geometry of the structure, which can cause stress
concentrations to develop, especially at abrupt changes in plan or elevation; and
provisions for insulation, cooling, and heating, which affect the ability of a building to
dampen the severity of outside temperature changes. In addition to these variables,
the amount of movement in a building is directly related to the type of aggregate,
cement, mix proportions, admixtures, humidity, construction sequence, and curing
procedures used.
The Need for Joints
Due to the low tensile capacity of concrete, some cracking in reinforced concrete is
unavoidable. Contraction joints provide a weakened plane for cracks to form.
Through the use of architectural details, these joints can be located so that cracks
will occur in less conspicuous locations within a building and possibly be eliminated
from view.
Expansion joints allow thermally induced
movements to occur with a minimum build-up
of stress. The greater the spacing; between
joints the greater the stresses. Typically, these
joints isolate a frame into a series of segments
with enough joint width to allow the building to
expand with increasing temperature. By
isolating the segments, expansion joints also
provide relief from cracking due to contraction,
and therefore act in a dual role.

Crack control in reinforced concrete buildings is needed for two reasons. The
obvious reason is aesthetics. Where cast-in-place concrete is to be the finished
product, cracks are unsightly. Cracks in major framing elements such as girders and
columns tend to promote questions concerning the structural adequacy of the
structure. They may, in fact, pose no structural problems, but to the average person
without structural knowledge, they can be cause for alarm. Secondly, cracks of
substantial width invite air and moisture into the framework of the structure, possibly
having deleterious effects.
Contraction/Control Joints
Contraction/control joints are placed in concrete slabs to
control random cracking. A fresh concrete mixture is a fluid,
plastic mass that can be molded into virtually any shape, but
as the material hardens there is a reduction in volume or
shrinkage. When shrinkage is restrained by contact with
supporting soils, granular fill, adjoining structures, or
reinforcement within the concrete, tensile stresses develop
within the concrete section. While concrete is very strong in
compression the tensile strength is only 8 to 12 percent of the
compressive strength. In effect, tensile stresses act against
the weakest property of the concrete material. The result is
cracking of the concrete.
There are two basic strategies to control cracking for good overall structural
behaviour. One method is to provide steel reinforcement in the slab which holds
random cracks tightly. When cracks are held tightly or remain small, the aggregate
particles on the faces of a crack interlock thus providing load transfer across the
crack. It is important to recognize that using steel reinforcement in a concrete slab
actually increases the potential for the occurrence of random hairline cracks in the
exposed surface of the concrete.
The most widely used method to control random cracking in concrete slabs is to
place contraction/control joints in the concrete surface at predetermined locations to
create weakened planes where the concrete can crack in a straight line.
This produces an aesthetically pleasing
appearance since the crack takes place
below the finished concrete surface. The
concrete has still cracked which is normal
behaviour, but the absence of random
cracks at the concrete surface gives the
appearance of an un-cracked section.
Concrete slabs-on-ground have
consistently performed very well when
the following considerations are
addressed. The soils or granular fill supporting the slab in service must be either
undisturbed soil or well compacted. In addition, contraction joints should be placed to
produce panels that are as square as possible and never exceeding a length to width
ratio of 1.5 to 1 (Figure 1). Joints are commonly spaced at distances equal to 24 to
New tool for slab joints reduces
concrete cracking.

30 times the slab thickness. Joint spacing that is greater than 15 feet require the use
of load transfer devices (dowels or diamond plates).
Slab Thickness, mm
Maximum-size Aggregate
Less than 19 mm
19mm and Larger
100 2.4 3.0
125 3.0 3.75
150 3.75 4.5
175 4.25 5.25
200 5.0 6.0
225 5.5 6.75
250 6.0 7.5
Figure 1a: Joint Spacing in Meters
Slab Thickness, mm
Less than 19 mm
19mm and Larger
4 8 10
5 10 13
6 12 15
7 14 18
8 16 20
9 18 23
10 20 25
Figure 1b: Joint Spacing in Feet
Contraction joints may be tooled into the concrete surface at the time of placement.
Joints may be tooled into the surface (first
pass) prior to the onset of bleeding or
immediately with the first pass of the floating
operation. The longer the first pass for
jointing is delayed the more difficult it will be
to shape clean straight line joints. Tooled
joints should be re-established with each
successive pass of finishing operations.
Joints may also be sawed into the hardened
concrete surface. It is important to
understand that the longer sawing is delayed the higher the potential for cracks to
establish themselves before sawing is complete. This means that any cracks that
occur before the concrete is sawed will render the sawed joint ineffective. Timing is
very important. Joints should be sawed as soon as the concrete will withstand the
energy of sawing without raveling or dislodging aggregate particles. For most
concrete mixtures, this means sawing should be completed within the first six to 18
hours and never delayed more than 24 hours. Early-entry saws are available which
may allow cutting to begin within a few hours after placement.

Contraction/control joints must be established to a depth of ¼ the slab thickness
(Figure 2). Proper joint spacing and depth are essential to effective control of random
cracking.
Figure 2: Minimum Depth of Contraction Joints
CONCRETE GROOVERS & JOINTERS
Jointing the concrete is accomplished by grooving tools (unless the slab will be saw-
cut later). The purpose is to control the location of cracks that may form when the
slab "contracts" due to drying shrinkage or temperature changes.
Look inside tooled joints or saw-cuts and you will see the concrete is cracked—the
joint did its job and controlled where the concrete cracked. Joints are most often
hand-tooled into sidewalks, driveways and patios and saw-cut into floors, highways,
and city streets.
Materials, Sizes and Bit Dimensions for Groovers
Groovers are usually made of bronze or stainless steel
and have a V-shaped bit that cuts the joint.
Like edgers, they come with wood or comfort-grip
handles.
The most common groover size is 6 inches long and 4
½ inches wide, but many other sizes are available,
ranging from 2 to 8 inches wide and 3 to 10 inches
long.
However, more important is the dimension of the bit, which can be anywhere from
1/2 inch to 2 inches deep and 1/8 to 1 inch wide. Bi-directional groovers are also
available and have double-end bits that give you the flexibility to cut forward or
backward.
Other Groover Products Available
Missile Groover
Aluminium Missile Groover available in 24”, 36”
48”, and 60” sloped front and rear so it won’t dig
an edge front and rear eye sights
Wagman Metal Products

Stainless Steel Groover
Marshalltown 180D Concrete Groover 6 x 3 ½ x ½
Groove. Blade made of stainless steel with a sturdy
steel mounting. Properly shaped bit and leading edge
cuts a sharp groove. Smooth comfortable handle is
securely attached. Cuts ½” x ½” groove.
Concrete Float
Kraft Tool CC814 Walking Magnesium Concrete
Float 24" x 3.25".
Concrete Jointer Buying Tips
• As with edgers, bronze or heavy-gauge stainless steel groovers will often
deliver the best durability and performance. Some stainless steel tools come
with highly polished finishes so they glide more easily through the concrete.
• The bit depth of the groover should be at least one-fourth the slab thickness to
create a sufficient plane of weakness along which the slab can crack. So if
you plan to groove a 4-inch-thick sidewalk, be sure to buy a tool with a 1-inch
bit depth.
• For stand-up use, walking groovers are available with features similar to those
of walking edgers. Or you can simply buy a special groover attachment that
secures to your metal bull float or Fresno trowel with thumb screws. Using
more than one of these attachments on a float or Fresno lets you cut multiple
grooves in one pass.
CONTROL JOINTS IN CONCRETE
When to cut, control joints; and proper spacing requirements.
It is important to be active in deciding where control
joints are placed. Often, jointing is not taken seriously
enough and the "saw-cutter" comes to your job and
puts the cuts where he feels they belong or where it
is convenient for him. And, most plans don't have
joint spacing marked on them. So don't leave this
important part of concrete construction to chance.
What are Control Joints?
Control joints are planned cracks which allow for
movements caused by temperature changes and
drying shrinkage. In other words, if the concrete does
crack-you want to have an active role in deciding
where it will crack and that it will crack in a straight
line instead of randomly.
When to Cut Control Joints
Make sure you are cutting joints soon enough. In hot weather, concrete might crack
if joints are not cut within 6-12 hours after finishing concrete. In this condition, if you
don't want to use a grooving tool to cut joints, there are early-entry dry-cut lightweight
saws that can be used almost immediately after finishing. These saws cut 1" to 3"
deep, depending on the model.
Correctly laid out joints.
Note: Inside corners, where
cracks would typically occur,
have correctly placed joints.

Control Joint Spacing
Space joints (in feet) no more than 2-3
times the slab thickness (in inches). A 4"
slab should have joints 8-12 feet apart.
When arranging joints, skilled contractors
will often use them to create an attractive
diamond pattern. If your concrete will be
stamped, ask about the best ways to avoid
interrupting the pattern with control joints.
More Jointing Tips
• Cut Joints Deep Enough.
Cut joints 25% of the depth of the slab. A 4" thick slab should have joints 1"
deep.
• How to Cut Joints.
Groover tools cut joints in fresh concrete. Saw
cutting cuts joints as soon as the concrete is hard
enough that the edges abutting the cut don't chip
from the saw blade.
• Place Joints Under Walls or Under Carpet Areas.
Under walls they won't be seen. Under carpet areas
the joints won't have a chance to telegraph through
vinyl areas.
• Avoid Re-Entrant Corners.
Planning the joint pattern can sometimes eliminate re-entrant corners.
Control Joint vs. Expansion Joint
Control joints are meant to control cracking, while expansion joints are meant to
allow for movement. Expansion joints, or isolation joints, are used between two
different concrete pours, or where concrete meets with another material or even a
structure. Expansion joints are more common on big commercial projects and often
aren’t required when pouring residential slabs. These joints usually require filling,
especially if the concrete is going to be polished or finished with a coating.
ISOLATION JOINTS
Joints that isolate the slab from a wall, column or
drainpipe
Isolation joints have one very simple purpose—they
completely isolate the slab from something else. That
something else can be a wall or a column or a drain
pipe. Here are a few things to consider with isolation
joints:
• Walls and columns, which are on their own
footings that are deeper than the slab sub-
grade, are not going to move the same way a
slab does as it shrinks or expands from drying or temperature changes or as
the sub-grade compresses a little.
Concrete Groover (Placing Control
Joints in Fresh Concrete)
Even wooden columns
should be isolated from
the slab.

• If slabs are connected to walls or columns or
pipes, as they contract or settle there will be
restraint, which usually cracks the slab—
although it could also damage pipes (standpipes
or floor drains).
• Expansion joints are virtually never needed with
interior slabs, because the concrete doesn't
expand that much—it never gets that hot.
• Expansion joints in concrete pavement are also
seldom needed, since the contraction joints open
enough (from drying shrinkage) to account for
temperature expansion. The exception might be
where a pavement or parking lot are next to a
bridge or building—then we simply use a slightly wider isolation joint (maybe
¾ inch instead of ½ inch).
• Blowups, from expansion of concrete due to hot weather and sun, are more
commonly caused by contraction joints that are not sealed and that then fill up
with non-compressible materials (rocks, dirt). They can also be due to very
long un-jointed sections.
• Isolation joints are formed by placing preformed joint material next to the
column or wall or standpipe prior to pouring the slab. Isolation joint material is
typically asphalt-impregnated fiber-board, although plastic, cork, rubber, and
neoprene are also available.
• Isolation joint material should go all the way through the slab, starting at the
sub-base, but should not extend above the top.
• For a cleaner looking isolation joint, the top part
of the preformed filler can be cut off and the
space filled with elastomeric sealant. Some
proprietary joints come with removable caps to
form this sealant reservoir.
• Joint materials range from inexpensive asphalt-
impregnated fiber-board to cork to closed cell
neoprene. Cork can expand and contract with
the joint, does not extrude, and seals out water.
It’s been said that the required performance is
what determines the choice of joint materials.
How much motion is expected, exposure to salts
or chemicals, and the value of the structure
would all come into play—and of course the cost.
• At columns, contraction joints should approach from all four directions ending
at the isolation joint, which should have a circular or a diamond shaped
configuration around the column. For an I-beam type steel column, a pinwheel
configuration can work. Always place the slab concrete first and do not install
the isolation joint material and fill around the column until the column is
carrying its full dead load.
Very long un-jointed
sections can expand
enough from the hot
sun to cause blowups,
but this is rare.
Polyethylene foam
isolation joint material
comes in various colors.
C2
Products.

SEALING JOINTS
Things to consider: when sealing, or filling concrete joints on floors.
Sealers and fillers for concrete joints are not the same thing and have very different
purposes. While it's not always necessary to seal or fill a joint, here are a few things
to think about:
• A sealer is soft and able to accommodate the concrete slab's expansion and
contraction. The sealer's purpose is to prevent water, ice, and dirt from getting
into the joint (and into the sub-grade) and to prevent intrusion from below the
slab--including of radon. Sealers can also improve the appearance of floors
and slabs.
• A filler is a rigid material that supports the edge of the joint when heavy traffic
crosses, like this polyurea joint filler from Specguard. This type of material is
only effective with saw-cut joints; rounded tooled edges can't support the filler.
• Both sealers and fillers should only be
installed after the slab has had a chance
to shrink as much as possible. Fillers are
only effective if installed after the
concrete has gone through most of its
shrinkage, although that can take a year
or more. Fillers and sealers should be
checked at the end of the first year of
service and repaired or replaced as
needed.
• Effective sealant materials must bond to
the concrete, be impermeable, and be
able to handle the expansion and
contraction.
• Before installing a sealant, the joint must be dry and free of dust and debris.
Vacuum it thoroughly before sealing. Carefully follow the sealant
manufacturer's installation instructions.
• For sealers, use a bond breaker or backer rod in the bottom of the joint. This
prevents the sealer from sagging into the joint and from adhering to the
bottom of the joint, which allows the
sealant to stretch on both the top and the
bottom.
• A backer rod in the joint also keeps the
sealer plug thinner, reducing the amount
of sealant needed.
• Although the best theoretical shape of the
sealant plug would be 1:2 (depth-to-width
ratio), ACI 504R-90, Guide to Sealing
Joints in Concrete Structures,
recommends that a better ratio is 3:2,
since this allows the sealant to adhere
better to the sides of the joint. Newer
sealers, however, may work at lower
ratios.
Sealers must bond to the
concrete and be
impermeable. Courts and
Cracks
Sealed joints should have a
backer rod or bond breaker in
the bottom.

1. These are planned cracks which allow for movements caused by temperature
changes and drying shrinkage.
A. Control Joints.
B. Crack Joints.
C. Conjunction Joints.
D. Standard Clip Joints.
2. __________ can be planes of weakness to control the location of cracks.
A. Groovers.
B. Joints.
C. Fasteners.
D. Ties.
3. _________ in reinforced concrete is needed for aesthetic reasons and
structural adequacy of the structure.
A. Joint Control.
B. Elevation Control.
C. Crack Control.
D. Movement Control.
4. These mason tools are usually made of bronze or stainless steel and have a
V-shaped bit that cuts the joint.
A. Smoothers.
B. Groovers.
C. Dividing Tool.
D. Standard Tool.
5. They provide a weakened plane for cracks to form. Through the use of
architectural details, these joints can be located so that cracks will occur in
less conspicuous locations within a building and possibly be eliminated from
view.
A. Crack Joints.
B. Control Joints.
C. Stability Joints.
D. Contraction Joints.

1. A. Control Joints.
2. B. Joints.
3. C. Crack Control.
4. B. Groovers.
5. D. Contraction Joints.

TASK SHEET NO.: 1.1
Title: How to Lay Concrete Blocks?
Standard
Guidelines:
• Laying concrete blocks down requires time, effort and a good
bit of supplies, always plan you tasks to avoid unnecessary
delays.
• Different construction companies have different standards in
Laying Concrete Blocks.
Performance
Objective:
The Trainee should be able to effectively and efficiently Lay
Concrete Blocks.
Tools /
Equipment:
• Trowel.
• Garden Hose.
• ⅜" and ⅝" Plywood.
• Work Gloves.
• Level.
• Wheelbarrow.
• 100' of Cord.
• Mortar.
• Masonry Chisel.
• 2x4 for Framing.
• Tie-in-Bars.
• Mortar Boards.
Steps /
Procedures:
Steps in Laying Down Concrete Blocks.
• Gather the Basic Tools.
• Prepare or Purchase Footing.
• Understand Available Blocks.
• Prepare the Footing.
• Understand the Importance of Footing.
• Prepare the 2 x 4’s.
• Prepare Concrete.
• Be Aware of the Area.
• Pour the Base Concrete.
• Wait for the Footing to Dry.
• Prepare to Lay Concrete Blocks.
• Plan the Section of the Corners.
• Determine the Number of Blocks.
• Prepare Cement Mortar.
• Start Laying the Concrete Blocks.
• Spread the Mortar Along the Corner.
• Set the Corner Block.
• Apply Mortar to the Side.
• Continue to Lay the Concrete Blocks.
• Check the Alignment.
• Apply Mortar to the Top.
• Stack the Blocks.
• Add the Reinforcement.
Assessment
Methods:
• Demonstration with Oral Questioning.
• Actual Demonstration.
• Role-plays.

TO ACCESS MORE
ABOUT THE MODULE
PLS CONTACT:

MASONRY NC II - CBLM

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