Optimum value and engineering & integrated design

Optimum Value Engineering
&
Integrated Design

OVE/ID
Background
● OVE/ID is little more than applied common sense.
● OVE/ID concepts are not new,
in fact they have been
in use by some builders
for three or four decades.
● Fits nicely with the “House As
A System” philosophy
New technology???
T. Eaton Co. mail-order houses
which used 24” o/c spacing for
the wall studs (circa. 1920).

Optimum Value Engineering (OVE)
What Is It?
● Can be defined as a construction philosophy in
which components and systems are designed to
meet their intended objectives without excessive
or unnecessary use of resources.
● In practice, most houses (both new and existing)
are over-designed relative to what is required by
the National Building Code – especially from a
structural perspective.
● Thus, money is expended without any
corresponding benefit.
24 members to protect a
plumbing chase??

Integrated Design
What Is It?
● Can be defined as a design approach in which all design
requirements are considered simultaneously rather
than sequentially.
● This permits their competing design requirements to be
better balanced.
● Parallels the famous “House As A System” philosophy
used by the R-2000 Standard.

OVE/ID
OVE/ID Measures Fall Into Three Categories
a) Framing measures
b) Mechanical system measures
c) Overall design measures

OVE/ID
a) Framing Measures
1. Design the house using 600 mm (24”) modules for
the walls, floor and attic framing. Since most board
materials (drywall and sheathing products) are also
based on this dimension, wastage is
automatically reduced.

Design Using A Modular 600 mm (24”) Layout

OVE/ID
Framing Measures (con’t)
2. Align the structural loads for the attic, walls and
foundation which permits direct transfer of loads
and allows unnecessary framing materials
to be eliminated.

OVE/ID
Framing Measures (con’t)
3. Coordinate wall openings with the basic 600 mm (24”)
dimension thereby reducing the number of studs,
cripples and other components

Coordinate Openings With The Modular Layout

HOT2000 Can Model The Benefits Of
Many OVE Framing Techniques

OVE/ID
b) Mechanical system measures
- Aligning mechanical systems to avoid unnecessary runs
- Designing the mechanical system based on need rather
than historical practice
c) Overall design principles
- Optimizing window selection

Benefits Of OVE/ID
● Lower construction costs – more intelligent design results in lower costs.
● Reduced wastage of framing materials creates environmental benefits.
● Reduced heat loss – reduced use of framing materials means fewer
thermal bridges.

Disadvantages Of OVE/ID
● More careful design practices are required
(more thought).
● Better site supervision is required – at least initially.
● Potentially negative homeowner perception – “less
wood means cheaper construction??” – NO!
OVE means “more insulation” not “less
wood”.

OVE/ID Measures
a) Framing Measures
1. Exterior wall framing at 600 mm (24”) o/c
2. Floor framing at 600 mm (24”) o/c
3. OVE framing
4. Optimum joist length and beam location
5. Elimination of floor system cross-bracing
6. Support of non-load bearing partition walls
7. Drywall clips at corners
8. Non-Load Bearing partition walls
9. Coordinated framing for windows and doors
10. Elimination of lintels in non-load bearing walls

OVE/ID Measures
b) Mechanical System Measures
11. Simplified plumbing stack venting
12. Core distribution for forced air heating systems
c) Overall Design Principles
13. Optimized window selection

1. Exterior Wall Framing At 600 mm (24”) o/c
Background
● The vast majority of Canadian houses use 400 mm (16”) o/c
stud spacing for exterior wall construction.
● This exceeds the NBC requirements – 400 mm spacing is
only needed structurally required when the wall is
supporting two or more floors.
● Why? (“Cuz that’s how we’ve always done it.”).
.

OVE/ID Alternative
● Use 600 mm (24”) o/c spacing unless narrower spacing
is structurally required.
● Use wider insulation batts to fit the wider wall cavities.

Advantages (to the builder)
● Reduced labour and material costs (eliminates 1/3 of
all wall studs).
Advantages (to the homeowner)
● Reduced thermal bridging meaning fewer building
envelope problems.
● Energy saving: average of 225 kWhe/yr
(worth $11 to $22 per year).

Cost Savings
● Typical new house: $270, assuming 13 mm (1/2”) drywall is used.
● If 16 mm (5/8”) drywall is used to reduce deflection, then
savings are reduced to about $44 per house.
● Material savings, per floor (imperial units)
= (0.25) x (wall perimeter, ft) x (stud cost)
- [(0.031) x (wall area) x (insulation cost / ft2)
Material savings, per floor (metric units)
= (0.82) x (wall perimeter, m) x (stud cost)
- [(0.031) x (wall area) x (insulation cost / m2)]
● Labour savings = 1.2 x (material savings)

2. Floor Framing At 600 mm (24”) o/c
Background
● Structural requirements for floors are largely dictated by
the need to control vibration, improperly designed
floors tend to be springy.
● However, some builders automatically use 400 mm (16”) o/c
spacing when 600 mm (24”) would meet code requirements.
● Structural requirements for dimensioned wood floor systems
are defined in the “Span Tables” of the NBC.
● If an engineered floor system is used (wood I-joists, wood or
metal web systems, etc.), then design to the manufacturer’s

OVE/ID Alternative
● Frame dimensioned wood floor systems with the floor
joists spaced 600 mm (24”) o/c, if permitted by the
NBC Span Tables.
● Generally not applicable to house which use engineered
floor systems.
● May require a thicker sub-floor, which reduces the
savings by about 25%.

● Reduced labour and material costs.
● Energy saving: none.

Cost Savings
● Typical new house: $450, if sub-floor thickness is unchanged.
$320, if thicker sub-floor is required.
Case 1 – Sub-floor thickness unchanged
● Material savings (imperial units)
= (0.25) x (floor area, ft2) x (joist cost per foot)
Material savings (metric units)
= (0.82) x (floor area, m2) x (joist cost per metre)
● Labour savings = (0.47) x (material savings)
Case 2 – Sub-floor thickness increased
= (0.25) x (floor area, ft2) x (joist cost per foot) – (0.094) x (floor area, ft2)
Material savings (metric units)
= (0.82) x (floor area, m2) x (joist cost per metre) – (floor area, m2)
● Labour savings = (0.72) x (material savings)

3. OVE Framing
Background
● This ties measures 1. and 2. together with roof trusses
spaced 600 mm (24”) o/c to permit direct load transfer.
● This allows the second top
plate to be eliminated but
requires metal connectors
to tie in the partition walls.
● Major issue is the availability
of pre-cut 2.39 m
(94 1/8”) wall studs.

3. OVE Framing
OVE/ID Alternative
● Align the roof trusses, wall studs and floor joists to
permit direct transfer of roof loads.
● Eliminate second top plate from exterior walls and
interior partitions and tie two wall systems together
with metal connectors.
● May not be applicable to houses with complicated
floor plans or geometry.

3. OVE Framing
● None.

3. OVE Framing
Cost Savings
● Typical new house: $100, assuming that 2.39 m (94 1/8”) studs
are available with the extra length costing the same per unit length
as the studs.
= [(0.94) x (stud cost per foot) + 0.14] x (wall perimeter, feet)
= [(0.29) x (stud cost per metre) + 1.33] x (wall perimeter, metres)

4. Optimum Joist Length
And Beam Location
Background
● When dimensioned lumber is used for the floor, off-centre joist splices can
be used to maximize the use of even-length members & eliminate overlaps.
● Alternatively, if joist lengths on each side of the beam have the same length,
the beam can be offset slightly so the butt joints are located over the beam.

And Beam Location
OVE/ID Alternative
● Applicable to house which use dimensioned lumber
floor systems.
● Use splices in the floor joists to reduce wastage.
● Alternatively, use floor joists of the same length on each
side of the beam and offset the beam so the joist butt
joints can be positioned over the beam.

And Beam Location
● None.

And Beam Location
Cost Savings
● Typical new house: $50, assuming an average of 0.6 m (2’) of
joist length can be saved for each joist spanning from wall to
wall.
= [(floor area, ft2) / (28) + 2] x (joist cost per foot)
= [[(floor area, m2) / (8.54) + 2] x (joist cost per metre)
● Labour savings = 0

5. Elimination Of Floor Cross-Bridging
Background
● 38 x38 (2x2) cross-bridging is used on many dimensioned floor systems
In many instances, the cross-bridging can be eliminated if furring strips
(19x19, 1x4) are nailed to the undersides of the joists.
● Alternatively, a panel-type ceiling can be used underneath
the joists.

OVE/ID Alternative
● Applicable to houses dimensioned lumber
floor systems.
● None.

Cost Savings
● Typical new house: $110.
= [(floor area, ft2) / (5.1)] x (cross-bridging cost per foot)
= [(floor area, m2) / (1.6)] x (cross-bridging cost per metre)

6. Support Of Non-Load Bearing
Partition Walls
Background
● Partition walls which are not load-bearing and run parallel
to the floor joists do not require a double floor joist
underneath them.
● The National Building Code of Canada permits wood
blocking to be used (typically 38x89 (2x4) members)
spaced 1.2 m (4’) underneath the partition wall
.

Partition Walls
OVE/ID Alternative
● Use wood blocking, such as 38x89 (2x4) members at 1.2 m (4’) o/c, under
non-load bearing partition walls instead of doubled floor joists.

Partition Walls
● None.

Partition Walls

Cost Savings
● Typical new house: $240, with the greatest savings occurring
with larger houses.
= (0.8) x (wall perimeter, ft) x (joist cost per foot)
=(0.8) x (wall perimeter, m) x (joist cost per metre)

7. Drywall Corner Clips
Background
● Three-stud corners are the norm in wood
wood frame construction with two studs
structurally supporting the ends of the
walls and the third providing backing
for one edge of the drywall.
● Structurally, the third stud can be
eliminated and replaced with drywall
clips.

OVE/ID Alternative
● Eliminate third stud at corners and use three drywall clips
to support the end of the intersecting sheet of drywall.
● Only applies to inside corners. Can also be used for other
applications such as intersecting partition walls and to
minimize problems with truss uplift.
● Also, very useful for retrofit applications.

● Reduced wood usage.
● Reduced thermal bridging meaning fewer building
envelope problems.

Cost Savings
● Typical new house: $16
● Material savings, per floor
= ($3) x (number of inside corners)

8. Non-Load Bearing Partition Walls
Background
● Non-load bearing partition walls are typically constructed
of 38x89 (2x4) members spaced at 400 mm (16”). This is
structurally excessive.
● With the exception of plumbing walls (normally built with
38x140’s, 2x6’s) and walls which contain heating ducts,
there is no reason for thicker walls.

OVE/ID Alternative
● Use 38x64 (2x3) studs at 600 mm (24”) o/c instead of
38x89 (2x4) studs for non-load bearing partition walls.
● May be perceived as flimsy construction by some
consumers.
● May require reduced jamb width for doors in partition
walls.

● Slight increase in useable floor area.

Cost Savings
= (2) x (wall perimeter, ft) x (2x4 stud cost per foot)
=(2) x (wall perimeter, m) x (38x89 stud cost per metre)

9. Coordinated Framing For Window
And Doors
Background
● The locations of windows and doors are usually dictated by aesthetic
concerns with little thought about the impact on framing.
● By making slight lateral adjustments to the locations of windows & doors
(on at least one side) to align with the existing stud spacing, the framing
can often be simplified and unnecessary studs and cripples eliminated.

And Doors
OVE/ID Alternative
● Modify the positions of windows and doors slightly so that
existing studs form one side of the rough-openings.
● This practice complies with the structural requirements
in the NBC.

4 members

5 members

Why not
9 members?

And Doors
● Reduced thermal bridging.
.

And Doors
Cost Savings
● Material savings
= [(2 x number of windows) + (number of doors)] x (wall stud cost)

10. Elimination Of Lintels In
Non-Load Bearing Walls
OVE/ID Alternative
● Eliminate all lintels in non-load bearing walls.

● Reduced thermal bridging.
.

Cost Savings
= 1.4 x ( number of doors & windows) x (lintel cost per lineal foot)
Material savings (metric units),
= 0.4 x ( number of doors & windows) x (lintel cost per lineal metre)

11. Simplified Plumbing System
Stack Venting
Background
● Plumbing walls are normally constructed with 38x140 (2x6)
framing to provide space for plumbing vents and water lines.
● If the house uses a floor plan in which the bathrooms,
kitchen and laundry rooms are dispersed, then more than
one plumbing wall may be required.

Stack Venting
OVE/ID Alternative
● Cluster the wet rooms (bathrooms, kitchen and laundry
room) around one plumbing wall.

Non-clustered

Clustered

Stack Venting
● Reduced air leakage (plumbing walls
tend to be extremely leaky).
● Slight increase in useable floor space
.

Stack Venting
Cost Savings
● Total savings (materials and labour),
= 50 x ( number of plumbing walls eliminated)

Air leakage occurring through a
plumbing wall into the attic

12. Core Distribution For Forced Air
Heating Systems
Background
● Heating grilles and registers are normally located under
windows to help keep them free of condensation - which
requires additional ductwork to reach the perimeter.
● However, this practice began when windows were
single-or-double glazed. Today’s windows are much more
resistant to condensation.
● Also, today’s building envelopes are much better insulated
and more airtight than their predecessors.

Heating Systems
OVE/ID Alternative
● Cluster the heating system grilles and registers around the central
core of the house, close to the furnace.
● Use high sidewall supplies, running through partition walls, if necessary.

High Sidewall Supply
Conventional Perimeter
Distribution System

Heating Systems
● Simplifies the house design since some of the usual
conflict between the heating/plumbing systems and
the structural design of the house is eliminated.
● Fewer problems with furniture placement, especially
if high sidewall supplies are used.
● Energy saving: (probably) none.
.

Heating Systems
Cost Savings
● Total savings (materials and labour), (imperial units),
= 25 x (floor area* / 125)
Total savings (materials and labour), (metric units),
= 25 x (floor area* / 12)
* = exclusive of basement area

13. Optimized Window Selection
Background
● Windows are usually the single most expensive component of the
the building envelope.
● The optimum window for a house can be defined as one which gives
the best compromise between cost and energy performance while
still achieving the desired durability.
● Numerous technologies (low-E films, gas fills, insulated spacers, etc.)
are commonly available which improve energy performance but
increase costs – sometimes significantly.
● Their performance depends on the house and its location.
● But, these treatments have wildly different costs. Which is the best
window for a given house in a given location?

OVE/ID Alternative
● Analyze the performance of various window options
using for the proposed house using HOT2000 (or
equivalent) and select the most cost- effective solution.

● Reduced costs.
● Improved comfort.
● Energy saving: potentially significant – up to 1000 kWh e/yr
.

Cost Savings
● Typical new house: potentially up to $1500, although this will vary
greatly. Savings are dependent upon the house and its location.
Window Costs*:
$13,300
$ 4,100
$ 4,200
$ 5,200
• All costs quoted by the
same manufacturer

Applying OVE/ID To A Typical New House

Example Of Measure #1
Exterior Wall Framing at 600 mm (24”) o/c
Assume a two-storey house with wall perimeters of 40.2 m and 32.3 m and a wall
area of 167 m2. If the studs cost $3.28 each and insulation costs $7.10/m2,
estimate the savings.
Material savings, per floor = (0.82) x (wall perimeter, m) x (stud cost)
- [(0.031) x (wall area) x (cost / m2)]
= (0.82) x (40.2 + 32.3) x (3.28) – [(0.031) x 167 x 7.10] = $158.24
Labour savings = 1.2 x (material savings)
= 1.2 x $158.24 = $189.89
Total savings = $158.24 + $189.89 = $348.13

Floor Framing at 600 mm (24”) o/c
Assume a two-storey house with a floor area of 141 m2. If the floor joists cost
$3.15 per metre, estimate the savings.
Material savings, per floor = (0.82) x (floor area, m2) x (joist cost per metre)
= (0.82) x (141) x (3.15) = $364.20
= 0.47 x $364.20 = $171.17
Total savings = $364.20 + $171.17 = $535.37

Elimination Of Floor System Cross-Bridging
Assume a two-storey house with a floor area of 141 m2. If the cross-bridging
costs $0.44 per metre, estimate the savings.
Material savings = [(floor area, m2) / (1.6)] x (cross-bracing cost per metre)
= [(141 / 1.6)] x (0.44) = $39.90
= 1.9 x $39.90 = $75.81
Total savings = $39.90 + $75.81 = $115.71

Elimination Of Lintels In Non-Load Bearing Walls

Assume a house with 20 windows and 4 doors. If the cost per metre of the
38x184 (2x8) material used for the lintels is $2.03, estimate the savings.
Material savings, per floor = (0.4) x [(no. of windows) + (no. of doors)]
x (lintel cost per lineal metre)
= (0.4) x (20 + 4) x (2.03 x 2) = $38.98
Note: since the lintel is composed of 2-38x184 (2x8) members, the cost per lintel
is equal to (2.03 x 2).
= 0.7 x $38.98 = $27.28
Total savings = $38.98 + $27.28 = $66.26

Core Distribution For Forced Air Heating Systems

Assume a two-storey house with perimeter air distribution system and a floor
area of 141 m2. Estimate the savings of a core air distribution system.
Total savings = 25 x (floor area, m2 / 12)
= 25 x (141 / 12) = $293.75

SUMMARY – WHAT HAVE WE LEARNED?
Optimum Value Engineering and Integrated Design are simply applied
common sense (this ain’t rocket science). They have been successfully
used in thousands of buildings over several decades.
Disadvantages
● They require re-thinking of conventional construction practices.
● OVE/ID introduces changes to the construction process (“change” = $).
● Consumers may have a negative reaction – “less material means
cheaper construction?”
Advantages
● OVE/ID saves the builder money.
● OVE/ID saves the homeowner energy and money.
● OVE/ID saves resources.

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