1. BACHELOR OF QUANTITY SURVEYING
(HONS)
BLD 60104 CONSTRUCTION TECHNOLOGY 1
By Azrina Md Yaakob
Azrina.MdYaakob@taylors.edu.my
CHAPTER 6
EXTERNAL ENVELOPE

2. 1.0 DEFINITION OF WALL
• Walls
are
the
ver+cal
elements
of
a
building
which
close
the
space
within
it
and
which
may
also
divide
that
space.
• Wall
+
Roof
=
building/environment
envelope

3. 2.0 IMPORTANCE OF WALL
• To
provide
shelter
against
wind,
rain
and
the
daily
as
well
as
seasonal
varia+ons
of
the
outside
temperature.
Therefore,
it
is
to
maintain
the
internal
comfort
for
the
building
occupants.
• To
provide
security
to
the
building
occupants
where
it
prevents
the
intruders
from
entering
the
premise
effortlessly.
• To
provide
sufficient
strength
and
stability
to
be
self-­‐
suppor+ng
and
also
support
for
roofs
and
upper
floors
• To
provide
a
means
to
divide
into
smaller
areas,
rooms
or
compartments
between
the
areas
inside
a
building.
• To
provide
adequate
sound
insula+on
to
reduce
the
transmission
of
sound
into
or
out
of
the
building.
• To
offer
adequate
resistance
to
fire
• To
look
aGrac+ve
and
sa+sfactorily
accommodate
windows
and
doors.

4. 3.0 CLASSIFICATION OF WALL
Basically,
wall
can
be
classified
according
to:
3.1
Loca9on
• Exterior
type
As
the
name
suggest,
exterior
walls
are
those
walls
that
exposed
to
the
exterior
environment
on
at
least
one
side.
• Interior
type
For
interior
wall,
both
sides
of
the
wall
are
exposed
to
indoor
environment.
Most
of
the
+me,
interior
wall
is
a
par++on
wall
that
divides
the
building
into
compartments
and
smaller
area.
Due
to
the
protected
environment
of
interior
wall,
it
is
allowed
to
be
made
of
lighter
materials
which
have
less
water
exclusion
capability.
3.2
Structural
requirements
• Load
bearing
wall
• Non-­‐load
bearing
wall

5. 3.2 STRUCTURAL REQUIREMENTS
• Loadbearing
Wall:
support
loads
from
floors
and
roof
in
addi9on
to
their
own
weight
and
resist
side
pressure
from
wind
and
some9mes,
from
stored
material
or
objects
within
the
building
• Non-­‐loadbearing
Wall:
carry
no
floor
or
roof
loads.
Each
type
may
be
further
divided
into
external
or
enclosing
walls
and
internal
dividing
walls

6. 3.2.1
LOAD-­‐BEARING
WALLS
• Load-­‐bearing
walls
carry
the
structural
weight
of
the
home.
Load-­‐bearing
walls
in
plaXorm-­‐frame
homes
will
have
double
top
plates.
That
is,
two
layers
of
framing
lumber.
• All
exterior
walls
are
load
bearing;
interior
walls
that
are
aligned
above
support
beams
are
also
load
bearing.
• A
load-­‐bearing
wall
carries
the
weight
of
the
building
and
distributes
that
load
onto
the
building's
founda+on.
The
load-­‐bearing
walls
which
are
easiest
to
iden+fy
are
the
home's
exterior
walls.

7. 3.2.1
LOAD-­‐BEARING
WALLS
(CONT’D)
• These walls carry the weight of the roof system. The roof
trusses rest on these walls and they create a continuous plane
all the way down to the building's foundation.
• In most residential walls, a second set of load-bearing walls,
one on each floor, exists along the centerline of the home.
• When a home is remodeled and changes are made to load-
bearing walls, the weight of the building must be supported
before, during and after the remodeling project. Before the
project commences, the builder must insert temporary support
which will carry the load during the project.
• Failure to do so can result in permanent damage to the home
as the weight of the building shifts because it is not supported
properly.

8. 3.2.2
NON-­‐LOAD-­‐BEARING
WALLS
• Non-­‐load-­‐bearing
walls
support
only
themselves;
they
are
interior
par++on
walls.
They
have
a
single
top
plate.
• They
will
not
be
aligned
above
support
beams.
• Non-­‐load-­‐bearing
walls
can
be
altered
or
even
removed
completely
without
weakening
the
home’s
structure;
altera+ons
that
can
be
made
to
load-­‐bearing
walls
are
limited.
• A
framed
wall
is
any
wall
in
the
home
that
is
not
a
load-­‐
bearing
wall.
Closets
are
a
typical
example
of
walls
which
are
not
load-­‐bearing
walls.
Also
called
par++on
walls,
framed
walls
create
the
internal
rooms
in
a
home.
They
can
be
moved,
removed
or
shortened
without
affec+ng
the
building's
structural
integrity.

11. 4.0
FUNCTIONAL
REQUIREMENTS
1.
Strength
and
stability
• Strength:
measured
in
terms
of
its
resistance
to
the
stresses
set
up
in
it
by
its
own
weight,
by
superimposed
loads
and
by
lateral
pressure
such
as
wind
• Stability:
resistance
to
overturning
by
lateral
forces
and
buckling
caused
by
excessive
slenderness.
2.
Weather
resistance
• provide
adequate
resistance
to
rain
and
wind
penetra+on.
• actual
degree
of
resistance
required
depend
largely
upon
its
height,
locality
and
degree
of
exposure
to
the
elements.
• Within
any
locality
there
can
also
be
varia+ons
of
exposure:
for
example,
a
site
near
the
coast
is
likely
to
present
greater
problems
of
rain
exclusion
than
one
some
distance
away.

12. 3.
Fire
resistance
• Used
to
compartmentalise
a
building
so
that
fire
is
confined
to
a
given
area
• To
form
a
safe
escape
routes
for
occupants
• To
separate
a
specific
fire
risk
within
a
building
• To
prevent
spread
of
fire
between
buildings
4.
Thermal
Insula9on
• To
provide
a
barrier
to
the
passage
of
heat
to
external
air
to
maintain
sa+sfactory
internal
condi+ons
without
a
wasteful
use
of
a
hea+ng/cooling
system
• Related
to
cavi+es
of
wall
5.
Sound
insula9on
• Only
upon
special
request
• Windows
are
weak
points
• Governed
by
thickness
and
weight
of
wall
4.0
FUNCTIONAL
REQUIREMENTS

13. 5.0 MATERIALS
Common types of material used for wall construction are:
• Bricks, concrete blocks or stone used for Masonry Wall
• Concrete (plain or reinforced)
• Timber or aluminium /steel sections with facing or
sheathings used in Frame Wall
• Reinforced plastics, metal, plywood or other suitable
material bonded to a core of foamed plastic to a relative
thin wall of high strength and low weight Membrane Wall.

14. 5.1 TYPES OF BRICKS
• Bricks are the most popular form of walling unit. Bricks are
chiefly made from burnt clay or shale, sand or flint and calcium
silicate or of concrete moulded in various ways to form blocks
of suitable and defined dimensions.
• Uniformity in the size of bricks is essential for the correct bond
to be facilitated during construction of a wall.The length of a
brick should be twice its width plus the thickness of one
vertical joint.
• Clay bricks 215 x 102.5 x 65mm; plus 10mm joint to give,
nominal size of 225 x 112.5 x 75mm.
• Concrete bricks 190 x 90 x 65mm; plus 10mm joint to give
nominal size of 200 x 100 x 75mm.

15. 5.1.1 CLAY BRICKS
There are three varieties of clay bricks known as common, facing and
engineering bricks.
• Common - suitable for general building work without any special
characteristic for an attractive appearance;
• Facing - specially made or selected to have an attractive
appearance when used without rendering or plaster,
• Engineering - having a dense and strong semi-vitreous body
conforming to defined limits for absorption and work strength.

17. 5.1.2 CONCRETE BRICKS
• Solid Bricks – those in which small holes passing through or
nearly through the brick do not exceed 25% of its volume, or in
which frogs do not exceed 20% of its volume. A small hole is
defined as a hole less than 20mm wide or less than 500mm2
in area.
• Perforated Bricks – those in which holes passing through the
brick exceed 25% of its volume and the holes are small as
defined above.
• Hollow Bricks – Those in which the holes passing through the
brick exceed 25% of its volume and the holes are larger than
those defined as small holes.
• Cellular Bricks – those in which the holes are closed at one
end and exceed 20% of the volume of the brick.

19. 5.2 BONDING OF BRICKS
• It is necessary to lay the bricks to some recognised pattern or bond
to ensure stability of the wall and to produce a pleasing appearance.
Bricks may be arranged in a variety of ways to produce a satisfactory
bond and each arrangement is identified by the pattern of headers
and stretchers on the face of the wall.
• Properly bonded brickwork distributes the load over as large an area
of brickwork as possible.
• The choice of the bond is influenced by the situation, function and
thickness of the wall:
ü Stretcher bond
ü English bond
ü Flemish bond

21. Stretcher Bond
• Stretcher bond is one of the simplest brickwork bonding consisting
entirely of stretchers throughout, with exception of a half bat which
must be placed at the stopped end at each alternate course. The
centre line of each stretcher is directly over the center line of the
cross joint in the course below.
• Used for half-brick walls only, such as partition and the leaves of
cavity walls;
• Half-bat is used to commence or finish alternate courses
• 3/4 bat is needed at junctions of cross-wall

22. English Bond
• A very strong bond consisting of alternate courses of headers and
stretchers
• Stretchers throughout the length of one course & headers
throughout the next course;
• In each headers course, a queen closer is placed next to a quoin
header.
• Stronger than Flemish bond because of there are n continuous
vertical joints
• Suitable for manholes & retaining walls

23. Flemish Bond
Double Flemish
• Requires fewer facing bricks than English bond, needing only 79
bricks per sq m compared to 89 for English bond;
• Not as strong because of the large number of sort continuous
vertical joints;
• Its appearance is considered to be better than English bond and is
more economical
Single Flemish
• A combination of English & Flemish bond, with Flemish bond on the
front face and a backing of English bond;
• Used to economise in expensive facing bricks where the expensive
facing bricks are used to give characteristic appearance of Flemish
bond and cheaper bricks are used as a backing;
• Slightly stronger than Double Flemish bond;
• Not applicable to walls less than one-and-a-half brick

25. TUTORIAL 6
• In a table form, explain the type of materials available
for internal and external wall.
• Item to be included in the tables are:
ü Suitability
ü Advantages
ü Disadvantages
ü Cost
Requirements:
You should prepare the table form which need to be presented.
Please state your name, student ID and title. (Group)