CMHC_notag_english.gif - 2 Kinvisible_pixel.GIF - 1.1 K previous more facts

Evaluation of Homes Constructed Under the Homeownership Assistance Program

Technical Series 94-204
Key messages
  • In 1983 the Northwest Territories Housing Corporation started the Homeownership Assistance Program. Families were provided with a package of building materials and plans to construct their own home.
  • An evaluation study in 1987 found that
  • Foundation problems occurred because the program did not allow for one year settlement of the pad before construction.
  • It was difficult to level the house because it was built close to the pad.
  • The superstructure was durable, except in cases where design modifications were made.
  • There were problems with frost build up on windows in houses with wood heating.
  • The awning style aluminum windows were not suitable for the climate.
  • Owner builders had fewer installation problems with asphalt shingles than with metal roofs. They found the drywall difficult to install.
  • Melamine veneer particleboard cabinets damaged easily and were difficult to repair
  • Icing of the vent stack was a common occurrence.

Typical HAP House
Figure 1. Typical HAP house Enlarged Image

Introduction

In 1983, the Northwest Territories Housing Corporation started the Homeownership Assistance Program (HAP). It was intended to make private housing available to those who could not purchase a home on their own. Clients meeting certain financial requirements and willing to provide the Asweat equity@, were provided with building material packages to construct their own houses. The packages came with all components necessary to complete the house, and had comprehensive instructions provided so that erection of the house was fast and efficient.

Because of the varying skill levels of the clients, a study was undertaken in 1987 to determine the success of the HAP houses presently in service. The houses were inspected and the clients were interviewed to determine the ease of construction, the quality of the materials provided in the package and the durability of the houses under northern conditions.

Construction

Building Site Preparation
The major problem encountered resulted from the fact that the standard HAP house kits were designed to incorporate a timber crib foundation on a standard gravel pad. The gravel pad specification had firm recommendations with respect to area beyond the house, slope at edges, etc. However, in many communities, especially in the High Arctic, gravel is expensive or not available. As a result, the gravel pads that were installed were often underbuilt. It is common practice to let a gravel pad sit for a year with no loading on it to allow settlement to take place and for the pad to adjust for the thermal regime of the permafrost. However, a one-year contract limitation prevented this. As a result of the poor site preparation, movement, settling and ponding problems were encountered.

Another concern with the program was the requirement to obtain a surveyed lot on which to construct the house. In many cases, surveyed lots were not available, requiring an additional delay to find a surveyor for the job.

Foundations

The major difficulty found with the design of the foundation was that because of the limited clearance between the house and the gravel pad it was difficult to level the house when settlement occurred. In cases where a gravel pad was not feasible, many owners used steel or wood pile foundations. Since the kit was designed for the house to sit on timber cribs, the clients had to fabricate and install their own connections from the piles to the house. The most common complaint with this system was that the house tended to vibrate from occupant movement and wind forces because of inadequate connections to the piles.

Standard Foundations for HAP houses
Figure 2. Standard foundations for HAP houses Enlarged Image

Superstructure

The superstructure of the HAP houses proved to be very durable, as no failures were reported when they were built according to the design. However, where on-site modifications were made without careful consideration of the design, some minor failures such as cracked drywall or window failure resulted. Minor failures, which could lead to long-term structural problems, were noted in houses that had structural members omitted or redesigned.

Building Envelope

The siding material used on HAP houses was pre-stained spruce, plywood or cedar. These materials seem to stand up well in northern conditions, but a true assessment was not possible because the evaluation took place within five years of construction.

The most common installation problems were gaps between the siding panels, or the lack of building paper between the sheathing and the siding.

One major problem was noted. Frost build-up on windows was a common occurrence in houses that were equipped with unit space heaters, especially wood stoves, while houses with a forced air heating system did not experience such phenomenon. The incidence of frost problems appeared to increase with the age of the house. No explanation for this was provided.

The awning-style windows supplied were not suitable for the climate. Frost build-up on the aluminum sill tended to bind the opening mechanism, causing bending of the aluminum weatherstripping and resulting in rainwater entry and air leakage. In addition, binding often resulted in broken handles and broken window glass. This was a particular problem because for some clients windows can be too expensive to repair or replace.

Some warpage of front entrance doors because of poorly fitting weatherstripping was also reported.

Air and vapour barriers were continuously upgraded during of the program. Later models used a 0.15 mm (6 mil) polyethylene vapour barrier on the inner side of the house envelope and spunbound olefin house wrap under the exterior sheathing. Condensation problems occurred only where the vapour barrier was discontinuous, such as at electrical outlets on exterior walls.

The more recent HAP houses were provided with higher levels of insulation: RSI 7.7 (R44), RSI 3.5 (R20) and RSI 8.3 (R47) in the floor, walls and roof respectively. Rigid mineral fibre insulation was placed over the ceiling batt insulation. In general, it was found that the installation of insulation was done well by all of the clients.

Two types of roofing material were available for the HAP houses: metal roofing, which was suggested to be better suited for the Arctic, and asphalt shingles, which are more common for houses below the treeline. In the study, it was found that the clients generally had fewer installation problems with the asphalt shingles. A small number of metal roofs had leaks, mainly at the junctions between the porch and the main roof, and at overlaps.

Typical Cross Sections of Hap Houses...
Figure 3. Typical cross sections of HAP houses with cathedral ceiling and truss roof systems Enlarged Image

The standard interior finish for the HAP houses was gypsum wallboard, which served as fire protection for the structural members of the house. Difficulties were encountered with the installation of the gypsum board; many of the clients hired professional drywallers. When the drywall became damaged due to wood shrinkage or foundation settlement, the clients often did not know how to repair the damage. Breakage and moisture damage to the drywall occurred in about five percent of the homes.

Interior finishes were another point of contention. It was found that the semi-gloss paint finish marked and scuffed easily, requiring washing or repainting in twelve percent of the homes.

The standard flooring was vinyl asbestos tile, with carpeting available for living rooms and bedrooms. Once again, when problems surfaced with the tile, many clients did not know what to do to correct the problem. In many cases, floor tile problems were caused by shifting in the foundation.

HAP houses were provided with pre-manufactured kitchen cabinets of melamine veneer particleboard. These units were easily damaged and difficult to repair. Dislike of the kitchen cabinet materials was common among the HAP clients surveyed.

In many instances, the homeowners had expressed a preference to change the interior finish of their homes. A number of clients would have preferred a system of credits that would have permitted interior finish upgrades, such as more use of carpeting, as their budgets allowed,

Mechanical Services

All of the HAP designs incorporated a complete plumbing package consisting of a bathroom sink, bathtub, toilet, stainless steel kitchen sink, hot water heater, and water and sewage storage tanks. Later additions included the connections for a clothes washer and dryer.

Where interior sewage tanks were installed according to the HAP plans, no problems were recorded. When the systems were modified to accommodate outdoor tanks, freeze-up problems occurred in almost all instances.

The only other problem with the systems concerned icing of the vent stack. This required many trips onto the roof to clear the stack.

Heating systems for HAP houses were oil-fired forced air furnaces. These were supplied complete with oil tanks and ductwork. Woodstoves were available to HAP clients below the treeline. Comments from the clients indicated that generally the houses retained heat well and handled moisture well. The major exception was for homes with wood as the primary heat source. Almost half of these homes experienced frosting on the windows.

Electrical services for the HAP houses were provided by contractors. No problems were reported with the electrical systems and only five percent of the clients were dissatisfied with the fixtures supplied.

Conclusion

In all, the HAP program has proved to be very beneficial to the North. Homes visited in all communities were generally well looked after and inhabited by a single family group. In general, houses were not crowded, and clients reported satisfaction with their homes as compared to previous housing available to them.


previous facts more facts
 
Home Page | Newsletters |Fact Sheets
Contacts | Northern Related Links | Bulletin Board
Upcoming Events | Jobs

Please send any comments or suggestions to AHFC.