Typical House Construction Process

Due to the wide variety of homes in terms of style and size, and the differences between professional builders and the do-it-yourselfer, it is difficult to say exactly what is a typical house construction process. Many factors apply, such as whether a single house or a whole subdivision is being built, as well as other factors such as weather, site conditions and the availability of labour and materials.

The description of the typical house construction process which follows is based on the wood-frame house construction techniques presented in this book. It assumes that a typical two- or three-bedroom house is being built by an average builder employing sub-trades. Special features, such as a sunroom, swimming pool or detached garage or workshop, are not included In this description. Before proceeding, it is interesting to review some Canadian housing statistics to appreciate how innovations in wood-frame house construction technology have decreased the time and effort required to construct a house.

The steady decline in construction time indicated In Figure 2 is due largely to the introduction of sheet and panel goods, such as drywall and plywood, factory-built components such as roof trusses, windows and cabinets, and plastic piping for sanitary plumbing. Specialized power tools and equipment also helped reduce manual labour. The shift from building one house at a time to building dozens, or hundreds at a time, is not specifically reflected in

Year

1943

1956

1965

1975

1985

1995

Housing Starts

59,900

115,420

155,128

180,952

180,000

110,993

Average Size

800 ft'

1,080 ft1

1,200 ft1

1,080 ff

1,230 ff

1225 ft'**

Average ^Selling Price

$5,500

$13,000

$17,400

$35,500

$80,500

$103,000

'Hourly Wage Carpenter

$1.05

$2.30

$3.46

$8.30

$18.37

Construction

Time

30 weeks

20 weeks

10 weeks

9 weeks

8 weeks

8 weeks

* These statistics have been gathered from a number of sources. They are indicative of era statistics and should not be treated as definitive. " Based on 1990 data

* These statistics have been gathered from a number of sources. They are indicative of era statistics and should not be treated as definitive. " Based on 1990 data these statistics, but should not be underestimated.

These statistics cannot be applied directly to the typical, individual house construction process being described here. Instead, use them as a guide for estimating a reasonable range of time needed to construct a dwelling. Normally, about 16 weeks is required from start to finish. If it is a very large or highly detailed building, 20 or more weeks may be needed. On the other hand, completing a small, simple dwelling may only require eight to ten weeks. This does not account for delays due to inclement weather, inspections, material shortages, custom-ordered items, or busy sub-trades during construction. Prior to construction, additional delays may be incurred while financing and a building permit are being obtained. The traditional need to set aside late spring, all summer and part of the fall for construction has not changed significantly for the single-house builder. At the same time, advances in Canadian home building have made construction an efficient, year-round activity in many parts of Canada.

STAGES OF CONSTRUCTION

There are a number of stages in constructing a house which must be properly planned, co-ordinated and executed by the builder. A short description of these has been provided following the typical construction sequence. It should be noted that the chapters which follow are presented according to this sequence.

Plans, Financing and Permits

This stage is also referred to as the pre-construction stage. The amount of time needed to develop a complete set

Schedule of stages in typical single house construction.

Average of 16 weeks for a typical house

Stage of construction

Plans, Financing and Permits* Layout of Building Excavation and Footings Foundations, Drainage and Backfill Framing (includes roofing and flashing) Doors and Windows

Plumbing, Heating and Electrical Rough-In Exterior Finishes

Insulation, Air and Vapour Barriers Interior Finishes Paint, Cabinets and Fixtures

Landscaping j

* Plans, financing and permits as well as any other aspects of the pre-construction stage will have a variable duration depending on site and house characteristics.

e of plans, estimate the cost of the dwelling, arrange for financing and obtain a building permit and all other required approvals, will vary considerably across the country. Providing access to the building site and arranging for temporary power may also take place during this stage. Because the time required for these factors is unpredictable, it has not been shown in Figure 3, but it should be taken into account.

Layout of Building

The first stage of construction involves layout of the building on the property. To properly observe the by-laws for setbacks to property lines, the services of a land surveyor may be required. Accurately laying out the excavation for the depth and placement of foundations is critical. Layout can usually be performed in a single day provided property boundaries do not need to be established. Site planning, on the other hand, to take advantage of the sun and wind, to manage drainage (runoff) and snow accumulation, and to afford a pleasing view, may require considerably more effort.

Excavation and Footings

Once the building layout is complete, excavation for the foundations may proceed. A single day is often all that is needed, provided appropriate equipment is employed and there is access to the excavation area. Another few days are needed to trench for and rough-in services, form and pour footings, remove footing formwork, layout the foundation walls and columns, and prepare to construct the foundations.

Foundations, Drainage and Backfill

Foundations can be installed in several days by a skilled sub-trade, including curing concrete and removing form-work. Dampproofing, foundation drainage systems and backfill will usually require another day or two. In some cases, unusual site conditions in unserviced areas may require additional measures for foundation drainage, such as sumps, ditching or dry wells. Properly storing topsoil and excavated material suitable for back-filllng can eliminate the need to import fill and topsoil. Placement of the granular layer and basement floor slab usually takes place later when the basement plumbing rough-in is completed.

Framing

Generally, about two weeks is needed to complete the framing and install roofing to provide weather protection during subsequent stages of construction. This assumes that temporary power is available for tools and equipment. Chimney installation and the building of stairs or the installation of pre-manufactured stairs is generally considered part of the framing stage. Typical arrangements with carpentry sub-trades vary across Canada. Where window and exterior door installation is included, about another week is needed to complete this stage. Framing decks is usually performed later.

Doors and Windows

Installing doors and windows, usually after framing is completed, requires a few days to a week to complete. Complete installation generally includes flashing and installing locks and related hardware. Jamb extensions and trim are typically part of the finishing carpentry work. The interior air sealing of gaps around window and door openings is commonly performed by the insulation and air/vapour barrier contractor.

Plumbing, Heating and Electrical Rough-in

This stage usually does not start until all framing is completed. Plumbing is brought from the service connections and roughed-in to the fixtures. Bathtubs and any large shower enclosures are generally installed at this time. The furnace and ductwork or piping is installed, along with ductwork for exhaust fans and mechanical ventilation equipment such as heat recovery ventilators (HRVs). Electrical wiring, smoke alarms, telephone and computer lines, and cable TV is roughed-in throughout the dwelling. The work requires about two weeks to complete, but does not include items such as woodstoves and fireplaces.

Exterior Finishes

Depending on the type of exterior finish being applied to the dwelling, between one and two weeks is needed to complete this stage. If an exterior air barrier, such as a house wrap, is being used, it is usually applied at this time, but it may also have been installed during the framing stage. Brick, siding and stucco along with soffit, fascia, eavestroughing, downspouts, and window and door caulking are all part of the exterior finishes stage. Exterior trim and millwork, staining and painting may also be carried out at this stage.

Insulation, Air and Vapour Barriers

This stage may be performed at the same time as exterior finishes, provided the insulation is protected against moisture damage caused by wind-driven rain. Installing insulation, air and vapour barriers requires a few days to complete when all of the detailing around penetrations, fixtures and outlets is included.

Interior Finishes

This stage typically begins with installing ceiling, wall and floor finishes. Finishing carpentry for interior doors, frames and trim along with stair balusters and handrails is generally carried out immediately after the floor, wall and ceiling finishes are prepared for painting and varnishing. The interior finishes stage normally requires about two weeks to complete, but significantly more time may be required depending on the type of finishes selected.

Paint, Cabinets and Fixtures

Painting and varnishing are usually performed at the beginning of this stage. Cabinets and items such as ceramic tile backsplashes are then installed. While this is proceeding, plumbers complete the installation of the plumbing fixtures, and electricians finish connecting circuits, receptacles, switches, light fixtures and smoke alarms. Connections to equipment such as furnaces, water heaters, mechanical ventilation systems, stoves and clothes dryers are also performed at this time. The heating contractor will install all grilles and registers for forced-air systems, and radiators for hydronic or electric baseboard systems. In some cases, appliances such as refrigerators, dish washers, stoves and dryers will also be installed at this time. All of the trades should ensure that their installations have been inspected and function properly, and then hand over any operating instructions and warranties to the builder or owner. A final clean-up of the dwelling concludes all work. About two weeks is normally required to complete this stage of construction.

Landscaping

This final stage includes finish grading, driveways, steps, walkways, groundcover, shrubs and trees. Carpentry work associated with decks and fences, and plumbing work for items such as underground sprinkler systems are also carried out at this time. Approximately one week is needed to carry out this final stage; however, the time will vary depending on the nature of the landscaping, and any special features such as decks and pools.

A summary of the stages of house construction, showing their sequence and duration, is depicted in Figure 3. Again, this should be viewed as a guide. It is important for do-it-your-self and less experienced builders to obtain advice on local conditions and practices. It is also important to add in several weeks time to allow for unavoidable delays.

APPROVALS, PERMITS AND INSPECTIONS

The system of approvals, permits and inspections for house construction can be quite complex for inexperienced and do-it-yourself builders. Practices differ among localities. However, the most important consideration before proceeding with house plans and specifications is to ensure that the property is zoned for residential use. For example, properties located in areas under the jurisdiction of a conservation authority may have many restrictions and requirements which apply to dwellings. Some properties may have development regulations, covenants or restrictions, governing the size, location and finishes of the house. Without knowing the zoning and environmental guidelines for construction, it is not prudent to proceed with the house design.

Requirements for plans, permits and inspections vary across Canada; however, most municipalities will conform to the basic requirements described in the National Building Code of Canada for plans. Plans should be drawn to scale and provide sufficient detail to enable a plans examiner to confirm that the house conforms to Code requirements. Most building departments will indicate the preferred format for house plans and the minimum information needed to obtain a building permit. Good plans also enable suppliers and sub-trades to properly supply and install materials and equipment. A complete set of plans and specifications should be prepared by a competent designer, the cost of which is often more than recovered through avoided extras and unforeseen problems.

Figure 4 shows the process of approvals, permits and inspections which may apply to a new house. It is recommended that readers consult their local building departments to obtain a complete list of forms and procedures. In some areas, it may be necessary to observe additional registration and inspection requirements by warranty programs for new houses. The scheduling of inspections to avoid lengthy delays is very important. It is advisable to determine exactly what work must be completed prior to calling for a particular inspection, as well as the amount of notice required. This

Approvals, permits and inspections process for new houses.

Zoning and Environmental Approvals r

Site Plan, Working Drawings and Specifications Y

Building Permit Plumbing Permit Heating Permit Electrical Permit Utility Permit (Gas/Propane) Health Unit Permit (Welts/Septic Systems) _________________Y_____________

Excavation and Footings Inspection

Sewers, Drains, Water Service and Underground Plumbing Inspection

Electrical Service Inspection

Pre-Backfill Inspection

Plumbing, Heating and Electrical Rough-in Inspection

Framing Inspection

Insulation and Air/Vapour Barrier Inspection

Pre-Occupancy Inspection

Final Plumbing, Heating and Electrical Inspection

Pre-Occupancy Inspection

Final Plumbing, Heating and Electrical Inspection

is most critical in remote communities where inspectors must travel long distances to perform inspections.

The many systems of approvals, permits and inspections in Canada are intended to maintain minimum levels of health and safety in new houses. It's important to understand the local requirements and plan ahead, so that the legal and adminis trative aspects of house building do not interfere with the actual construction of the house. Builders and their sub-trades can focus solely on the quality of their work when the paperwork associated with approvals, permits and inspections is handled properly. The following chapters present aspects of these stages of house construction in greater detail.

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