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PLANS, SPECIFICATIONS,
AND CODES
1
Introduction
In order to analyze the construction of residential buildings, the real estate appraiser should attain a reasonable
degree of skill in interpreting what is commonly known as a "set of plans".
These "plans", particularly in the residential market, generally consist of a number of pages of drawings and
notes describing, in two dimensions, the house or unit for consideration. Before describing these "pages" and
their contents, some terminology will be explained.
Drawings
The sheets of paper used for drawing have the following varied sizes:
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8½" × 11" or 8½" × 14": mostly for site plans or survey plans.
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11" × 17", 17" × 22", or 24" × 36": typically for plans, elevations, and details.
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30" × 42": used rarely, generally for larger houses or multiple-unit housing. These drawings are
usually reproductions of the original drawings either via photocopying or via Ozolid Printing.
Ozolid prints consist of blue or black lines on a white background and are often incorrectly called blueprints.
Blueprints are reproductions with a dark blue background and white lines and have not been used much since
the late 1940's. Ozolid printing must be done on a special machine utilizing special paper, and is often carried
out by a commercial reproduction company.
In contemporary design for residential and commercial applications, drawings are generally completed using
computer-assisted drafting and design (CADD) software. These programs allow architects, interior designers,
builders, building engineers, etc. to easily place walls, windows, doors, roofs, stairs, and other architectural
elements into a design and then quickly generate a three-dimensional model (as opposed to having to draw these
line by line). CADD modeling is very helpful both for design, in that it allows very effective visualization, and
for generating the detailed elevations, sections, and plans which are needed for construction.
Scales
Scales are factors of proportional size reduction which enable buildings, sites, furnishings, and fitments, etc.
to be drawn less than full size; i.e. small enough to fit the size of paper and yet large enough to show all the
necessary information. Scales typically fall into one of four categories:
1.
2.
3.
4.
architectural
engineering
metric
graphic
1.1
Chapter 1
Architectural Scale
Architectural scales are based on the division of one inch, and are typically noted as either:
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1/16"
3/32"
1/8"
3/16"
1/4"
1/2"
3/4"
1"
1½"
3"
=
=
=
=
=
=
=
=
=
=
1'0" (i.e., 1/16th of an inch on the drawing represents 1 foot in real size)
1'0"
1'0"
1'0"
1'0"
1'0"
1'0"
1'0"
1'0"
1'0" (or for larger sizes, noted "Half Full Size" or "Full Size")
In preparing a drawing, the draughtsperson utilizes a ruler or a scale marked on the edge of each side. Each
scale will group or "intermesh" two separate scales, one reading from right to left, and the other reading from
left to right. For example, one direction has markings for 1/8" and the other has markings for 1/4". Or, one
direction has 3/32" markings and the other 3/16". The two intermeshed scales always have one set of markings
that is twice as big as the other set. This gives 4 sets of markings on each side of a flat scale or 6 sets of
markings on each side of triangular shaped scale. Therefore, there will typically be a total of 8 scales on a flat
ruler (4 on each side) and 12 scales on a triangular ruler.
The architectural scale generally used for plans, sections, and elevations is 1/4"=1'0", or possibly 1/8"=1'0"
for larger buildings. The other scales are used for details or distinctive pieces of plans, elevations, or sections
that need to be drawn larger for greater clarity.
On a building site or for approximate reference, an ordinary tape measure could be utilized to measure, or scale,
a drawing in relation to the physical building. For example, to determine the length of a room from the drawing,
one could measure 2¾" which at a scale of 1/8"=1'0" would mean 22'0" in length (2.75" × 8).
A word of caution: when scaling a drawing, the resultant real dimension could differ from that on the drawing
because the print may have shrunk or stretched during the reproduction process. Therefore, one should always
utilize the written dimensions to be completely accurate. However, on occasion the initials "NTS", or not to
scale, may be noted beside a written dimension. This means that the written dimensions have been changed for
expediency, but the actual drawing has not been changed and therefore scaling the drawing will definitely result
in an incorrect dimension.
Engineering Scale
Engineering scales are based on the division of 1 inch by multiples of ten and are typically noted as either:
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1.2
1"
1"
1"
1"
1"
1"
=
=
=
=
=
=
10' (or 1"= 100' or 1"= 1,000')
20' (or 1"= 200' etc.)
30'
40'
50'
60'
Plans, Specifications, and Codes
The engineering scale (or ruler) is typically marked on the edge of each face, but each edge generally has only
1 scale reading left to right. Therefore, there are 4 scales on a flat ruler (2 on each side) and 6 scales on a
triangular ruler.
The engineering scale is typically used for site (or plot) plans and by a city to show the location of services, e.g.
sidewalks, roads, sewer and water, gas, etc. This scale is also used for legal and survey drawings.
Metric Scale
Metric scales are based on the division of one metre = 39.370077 inches, and are typically noted as:
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1:1
1:2
1:5
1:10
1:20
1:50
1:100
1:200
1:500
"Full Size" - 1,000mm represents 1,000mm or 1 metre
"Half-Full Size" - 500mm represents 1,000mm or 1 metre
(200mm represents 1,000mm or 1 metre)
(100mm represents 1,000mm or 1 metre)
(50mm represents 1,000mm or 1 metre)
(20mm represents 1,000mm or 1 metre
(10mm represents 1,000mm or 1 metre)
(5mm represents 1,000mm or 1 metre)
(2mm represents 1,000mm or 1 metre)
The metric scale is typically marked in the same format as the engineering scale, with 1 scale reading left to right
on each edge.
The metric scale is used for all types of drawings, both site plans and design drawings. Plans, elevations, and
sections typically use a scale of 1:50, which is approximately the same size as 1/4" = 1'0".
Graphic Scale
Drawings and documents are increasingly being reproduced in smaller, reduced formats, particularly if they are
stored on microfilm or microfiche. These reductions necessitate the use of a graphic scale.
This scale is presented as a horizontal bar or line marked off in units. A given distance on the plan can be
measured against this graphic scale to indicate the actual distance.
The advantage of a graphic scale is that, being on the original drawing, it is enlarged or reduced as the size of
the drawing is changed and therefore always remains in proportion to the drawing.
Some documents may have two graphic scales: one in Imperial measurement (i.e. feet, miles, etc.) and one in
Metric measurement (i.e. metres, kilometres, etc.).
Metric Construction Modules
The introduction of the metric system to the building industry has not been without some confusion. Part of the
misunderstanding surrounds the use of both soft changes and hard changes.
Soft changes involve the use of existing physical sizes now specified in metric measurement. For example, the
old faithful 2" × 4" (which is really the rough sawn imperial measurement for a planed piece of structural
1.3
Chapter 1
lumber 1½" thick and 3½" wide) is now specified 38mm thick and 89mm wide while the size remains
unchanged.
Hard changes involve the establishment of metric standards. For example, the metric building module is now
100mm. Multiples of this module are used by designers in planning room sizes and specifying distances between
structural members; for example, common spacing between floor joists is 300mm or 400mm, and the common
ceiling height in a metric home is 2,400mm. Another hard change involves the dimensions of sheet products.
Metric measurements for plywood, waferboard, gypsumboard and other such products becomes 1,200mm ×
2,400mm rather than 4N × 8N (Imperial).
Whether or not a home is constructed to metric standards can be determined by measuring the size of sheet
products (where edge seams can be detected) or by measuring the floor to ceiling elevation. In general, metric
building standards have not significantly altered the appearance of either the interior or exterior of homes.
Typical Design Drawings (Residential)
There are two main types of drawings that an appraiser will encounter: Design Drawings (or "Concept"
Drawings), which describe the general type and layout of a building, and Working Drawings, which are detailed
drawings used for construction. The major difference between Residential Design Drawings and Working or
Construction Drawings is that the Design Drawing will have far less (or no) details and dimensions.
A Residential Design Drawing is the type of drawing which is typically found in magazines, books of house
plans, builders' brochures, etc. Design Drawings typically focus only on liveable area, for example, the layout
of the main floor, second floor, etc. A Design Drawing would not generally include the basement unless it is
to be developed as living space. A Design Drawing could also include an adjacent front elevation and/or
perspective (a photograph-like drawing of what the house would look like when built).
These plans either have no indication of room sizes or areas, or note only the major room sizes, such as
4,521mm × 5,182mm (14'10" × 17'0"), meaning that the room is 4,521mm (14'10") wide by 5,182mm
(17'0") long. They may often note the total square footage of the unit, excluding any undeveloped basement.
If the room sizes are noted, one can develop a graphic scale utilizing the known dimensions. For example, if
the room length of 5,182mm (17 feet) is given, then 2 times the room length is 10,364mm (34 feet), 3 times is
15,546mm (51 feet) or ½ times is 2,591mm (8½ feet), etc. This can be used to determine the size of the whole
unit (width and length) or the size of rooms not designated.
Alternately, if room sizes are not shown, a graphic scale can still be determined utilizing the length and/or width
of common objects shown on the plan. For example:
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a typical bathtub enclosed by 3 walls is 760mm (2'6") wide by 1,520mm (5'0") long.
a typical kitchen counter is 600mm (2'0") deep.
a typical closet is 600mm (2'0") deep.
In either case, these graphic scales and the sizes determined by them are only very approximate. Actual sizes
can be determined only with a set of Working or Construction Drawings.
1.4
Plans, Specifications, and Codes
Working or Construction Drawings
A typical set of Working or Construction Drawings give much more detail than a set of Design Drawings and
should be sufficient to enable a builder to construct this unit. Construction Drawings would typically include
architectural and structural plans, and may also include plans for mechanical and electrical systems.
Architectural Plans
Site (or Plot) Plan
The Site Plan is usually drawn utilizing a Metric or Engineering scale and should contain the following
information:
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site size and corner angles if not 90 degrees;
abutting streets or lanes with proper names; and
location of unit and of outbuildings (i.e. garage, sheds(s), etc.) if specified in the contract.
In addition to the above, the Site Plan may also contain:
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location of electrical and telephone services, transformers, etc.
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location and size of water, sewer, storm sewer and gas mains.
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location and dimension of driveways, approaches, sidewalks, patios, decks, fences, overhead trellises,
etc. (collectively known as hard landscaping).
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elevation of the finished main floor above some reference point noted on the drawing (BM or bench
mark) or as Geodetic (height above sea level) and references to some public (City-established)
permanent bench mark.
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elevation of ground level as it exists at the four corners of the property (design grades) and the elevation
of ground level at the four corners of the house after it has been built (for a property which has a
dramatic slope, a topographic plan or "topo" may be used. This shows the existing contour lines and
their elevation, as well as the design contour lines which indicate the slope of the ground after
construction and site grading).
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landscape plan showing trees, shrubs, flowerbeds, etc. to be planted (known as soft landscaping).
Floor Plans
Floor plans are usually drawn at 1:50 or 1:100 (1/4" or 1/8" = 1'0") and should contain:
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basement plan noting furnace location, floor drains or sump pits, stairs, windows, slopes to concrete
floor, and column locations (if there is a basement).
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floor plans noting rooms, passageways, windows, doors, fittings (i.e., kitchen cupboards, vanities,
closets, etc.) stairs, projections, and fireplace.
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roof plan noting roof slopes, chimneys, vents, dormers, special construction, etc. (generally required
only on more complex house designs).
1.5
Chapter 1
Other Plans
Other types of architectural plans include:
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exterior elevations – all 4 or more faces of the house noting windows, doors, finish materials (i.e.,
brick, stucco, siding, etc.), often heights from basement or main floor, main to second, etc.
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cross sections (or sections) show the profile of the unit as if it were cut through by an imaginary plane
and note the construction materials used to construct the walls, floors, roof, stairs, etc. plus referencing
for further larger-scale details.
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wall sections and/or details – usually at a larger scale, showing more information on how to construct
items such as the fireplace, the basement foundation wall, the roof/wall junction, etc.
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finishing details (or finish elevations) – again at a larger scale, showing more detailed dimensions and
more information on how to construct items such as kitchen cabinets, planters, custom or complex wood
stairs, special wall panelling, etc.
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schedules: list of items and the respective information for each. For example, a door schedule will
indicate the size, frame material, and hardware for each door. A finish schedule will indicate the finish
for all floors, walls, and ceilings, including type of material and colour.
Specifications
Specifications are written, detailed explanations of the materials, installation, finishes and equipment included
in the house and supplement the drawings by providing more specific information. For example, a hot water
tank (HWT) may be located on the basement drawing. The specification would indicate in written format that
the HWT is a:
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Rheem RE 100-26 gal. tank, 6 KW input, 240 V single phase. Automatic temp. control. Glass lined
storage tank.
For smaller projects, these specifications may be hand lettered or typed onto the drawing. For larger or
architecturally designed projects, these specifications may be contained in a separate 8½" × 11" book.
Structural Plans
Structural Plans give detailed structural information for constructing the foundation, floors, and roof. It is
becoming more common for these structural drawings, or any structural information, to be "sealed", or required
to bear the stamp of a Professional Structural Engineer. Note that for simpler houses, this structural information
could be shown on the basement Architectural Plan.
Foundation Plan
The Foundation Plan is usually drawn at the same scale as the Basement plan and should include the following:
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1.6
soil test information indicating type and consistency of ground, as well as allowable bearing pressures,
settlement characteristics, etc.;
the location, size, and depth of piles or the depth and width of strip footings under the basement wall
and column footings; and
plan of basement wall showing the location, width, and height together with the extent of the basement
floor including details such as reinforcing steel, slopes, pits and depressions, etc.
Plans, Specifications, and Codes
Floor(s) and Roof Framing Plans
The Framing Plans should note column spacing and sizes, steel and wood beam locations and sizes, joist and
rafter spacing and sizes, floor and roof sheathing and thicknesses, floor and roof openings, roof slopes, slopes,
etc.
Section and Details
Section and Details illustrate structural situations which require more detailed explanations. For example:
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a cross section of the foundation showing its reinforcing and connection to the floor framing.
special connections, openings, beams, etc.
Mechanical Plans
Mechanical Plans typically show a plan of each level (including the basement) and note all mechanical
components. A Mechanical Plan would typically include information on the type and location of the following
components:
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all equipment such as fans, pumps, kitchen, and bathroom fixtures, etc.;
hot and cold water lines, sewer lines, plumbing stacks and vents;
heating equipment showing ducts, gas lines, hot water or steam lines, radiators, grills, etc. (although
electric baseboards would be shown on the electrical drawings);
ventilation ducts;
air conditioning unit size and connections;
underground connections to street services would be shown on the site plan;
swimming pool systems and connection (if the equipment is all outside the house there may be separate
pool drawing);
lawn sprinkler systems and connections are probably shown on a separate drawing which is incorporated
or added to landscape plan.
For almost all residential units, other than large and complex houses or custom units designed by an Architect,
the mechanical and electrical components would likely be shown superimposed on the architectural floor plans.
Electrical Plans
An Electrical Plan is similar to a Mechanical Plan, and indicates the location and type of electrical components
for each level including the basement. For example, an Electrical Plan would typically include the following
components:
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all electrical equipment or mechanical equipment requiring electrical power including fans, pumps, hot
water tanks, air conditioning units, etc.;
incoming service location, size and details (e.g. underground or overhead);
distribution and circuitry to wall power outlets, switches, lights;
telephone distribution and possibly television distribution (or at least the location of all phone and TV
outlets);
possible fire alarm or security systems, if extensive.
Note again that most residential units will have this electrical information superimposed on the Architectural
floor plans, and do not require a separate Electrical Plan.
1.7
Chapter 1
Current Building Standards
Prior to embarking on a detailed study of building technology, it is important to recognize that residential
construction has changed a great deal during the past few decades. In the past, structures were assembled with
more emphasis on the availability and endurance of materials, and less on other less tangible aspects.
Contemporary building technology is the result of sustained experience, systematic study of problems, and
considerable research leading to the development of new materials and methods. Not only is contemporary
technology concerned with strength and endurance, but also with comfort, convenience, efficiency, economy
and environmental factors.
Over time, building codes have been adopted to ensure that structures are safe and durable; however, building
codes and municipal bylaws are often misunderstood. People sometimes object to the fact that construction or
alteration of buildings requires a permit and/or an inspection. These requirements are in place to ensure not only
that the structural elements are strong and durable, but also that proper methods of construction have been
employed in assembling the building. Compliance with codes and regulations protects purchasers of residential
buildings by ensuring that established standards have been followed.
Building standards have been continually improved over the years. This becomes obvious when a home built
during the 1950s is compared to a contemporary home. The standards with respect to items such as electrical
wiring, insulation, and draft proofing have undergone significant change.
When determining if an older home meets current standards (for example, in quality of insulation), the answer
will depend on which year the home was built and whether the home has been renovated since that time. It is
impossible to tell whether a particular house meets today's building standards unless it can be established that
the home was built to a specified standard in place at the time the home was constructed.
Canadian builders have continually supported improved housing standards and, in 1972, formed a National
Steering Committee which initiated actions leading to the establishment of Home Warranty programs in each
province. These programs have been used fairly extensively in marketing new homes and may therefore have
some perceived value to homebuyers.
Building Codes
The central governing code or "bylaw" in Canada covering construction is the National Building Code. This
Code
is published by the National Research Council through its Associate Committee on the National
Building Code. It comprises a set of model technical requirements with respect to public safety
in buildings and is written in a form suitable for adoption by appropriate legislative authorities
in Canada.
NBC 1985
This code, although primarily set for Commercial/Industrial buildings (Parts 1 through 8), contains a section,
Part 9, that
provides detailed requirements for the construction of houses and small buildings up to 600m2
(6,459 SF) and 3 storeys in height, and applies to all occupancies except assembly, institutional
and high hazard industrial.
NBC 1985
1.8
Plans, Specifications, and Codes
This part (some 172 pages) is set out to control minimum standards of performance including design criteria
(e.g. minimum room sizes and heights), material specifications (e.g. minimum strength of concrete used for
carport floors) and installation procedures (e.g. the minimum size and number of screws or staples to attach
stucco wire to the outside of a house). These standards are minimum which, of course, does not preclude
constructing a dwelling at standards above these minimums. A reasonable understanding of this portion of the
Code is required with the ability to reference in detail certain aspects of it, if required.
The National Building Code may be adopted as is by a Province or Municipality intact, but in most cases, the
NBC is modified to some degree to reflect local concerns or unique conditions. This modified Code is then
legislatively accepted and made mandatory for that jurisdiction. For example, the province of British Columbia
has amended the NBC and retitled it the British Columbia Building Code (BCBC). The BCBC mostly follows
the NBC, but may have some areas of difference; for example, the BCBC now permits four storey wood
residential construction subject to specific conditions, such as the application of Parts 1 through 8 of the Code
to this building. The City of Vancouver operates under its own charter, and governs construction under the
Vancouver Building Bylaw. This document is different from NBC and BCBC in many areas. For example,
all new single or multi-family residential construction in Vancouver must be equipped with a fire suppression
sprinkler system. The legislative situation in other provinces and municipalities is similar to this. For example,
the building code for use in Manitoba is the Manitoba Building Code, but the City of Winnipeg has amended
the NBC and retitled it as Winnipeg Building Bylaw.
It must be noted that other codes or regulations may apply to a housing unit under consideration by an Appraiser.
These could be:
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Workplace Safety and Health Regulation;
Provincial Electrical Code;
Provincial Fire Code; or
Residential Buildings Fire and Safety By-Law, etc.
Materials Used in Residential Construction
The choice of materials used in the construction of residential buildings is dependent on a number of factors:
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cost
quality
ease of application
durability
maintenance requirements
The quality of contemporary building materials is controlled by regulations which specify minimum acceptable
standards. In Canada, most of these standards are set by Canadian Standards Association (CSA) or the
Underwriters Laboratory, Canada (ULC). Some material standards are established by agreement within an
industry; for example, the grading regulations for dimension lumber are established by the National Lumber
Grades Authority.
Durability is dependent not only on the chemical, mechanical and physical properties of a material, but also on
the harshness of the environment and the standard of personal use and care. Modern building technology
continues to produce new materials that are more durable and less demanding in terms of maintenance.
1.9
Chapter 1
Symbols and Abbreviations
By definition, a symbol is a mark or character which represents another object, idea, function, or process.
Using a symbol allows you to refer to something which is detailed or complex, in a simple and easy way.
In the production of Design, Working, or Construction Drawings, a set of symbols have been generally
standardized to mean the same thing in various parts of the country or continent. These symbols form a common
language so that architects, engineers, contractors, tradespeople, estimators, suppliers, and others who utilize
these drawings recognize these symbols in the same way and interpret the same meaning (see Figures 1, 2, and
3).
Abbreviations (utilized as a written shorthand) are similar to symbols in that they have been generally
standardized and represent the same information (although, as opposed to symbols, they often exhibit regional
differences). For example, concrete is written as "CONC", and carpet is written as "CP" or "CP(T)".
These symbols or abbreviations are generally trade- or systems- specific, that is, architectural, structural,
mechanical, electrical, etc. each have their own set.
Figure 1
Materials
1.10
Plans, Specifications, and Codes
Figure 1 continued
1.11
Chapter 1
Figure 2
Electrical
1.12
Plans, Specifications, and Codes
Figure 3
Mechanical
1.13
Chapter 1
Figure 4
Abbreviations
1.14