Building Envelope Inspection
18 May 2012

Building Envelope Inspection

John Fuglestveit

At this stage, Cedarglen is working on completing the exterior of the home and the main inspection goal is reviewing the building envelope. The building envelope is one of the most important parts of the home. It keeps the exterior elements from infiltrating the home; this is especially important due to the severe weather conditions we can experience in Calgary. The exterior envelope acts as an air barrier and drainage plane on the overall structure to prevent moisture accumulating in the walls and even penetrating into the interior of the home. In addition, correct envelope detail can also equate to a home that performs efficiently controlling the indoor and outdoor elements (your home as a system).

At Cedarglen, we have a long-standing relationship with our contractors who have been taught to follow our precise standard specifications when it comes to the exterior envelope details. Although there are no regulations set in place by The City of Calgary to have the exterior envelope inspected, at Cedarglen we perform an exterior envelope inspection to ensure that the customer receives the highest quality and performance when it comes to the exterior building envelope.

While inspecting the exterior envelope the main principle to keep in mind is how water will flow once it comes in contact with the building. Basically, the rule of thumb is that water always takes the path of least resistance so Cedarglen has taken the steps to ensure that water does not have the opportunity to enter the building. Cedarglen has designed all of our building envelope details to incorporate a shingle lap detail that will direct water away from the building. Shingle lap fashion means that all exterior material is lapped so that the bottom exterior detail is always under the top exterior detail to ensure that all water is directed out rather than in.

Starting at the top of the building with the roofing there are factors to make sure the water flows off the roof. Firstly, the roof is designed with a slope to shed water. Secondly, Cedarglen installs asphalt shingles, as a standard; these are installed in shingle lap fashion to prevent water from penetrating through the building envelope. In addition, any house with a roof slope under 8/12, we are installing roofing felt paper under the shingles as an additional drainage plane. Thirdly, at roof valleys and roof to house intersections, we install metal flashings to direct water away from the building. Lastly, in the roof we install roof vents for air circulation in the attic to keep exterior air and interior air in balance and minimize condensation.

For the wall sections, Cedarglen requires the following details to ensure a proper building envelope: Starting at the top of the wall, the framer installs a strip of weather resistant membrane to enable siders to tie into to maintain the shingle lap process. The framer installs insulation stops between the trusses over the membrane to ensure that the insulation stop is overlapping the membrane. Insulation stops provides a drainage plane to direct any condensation from the attic to the exterior of the building. Continuing down the house, weather resistant membrane will be installed behind adjoining members such as deck ledgers, cantilevers, exterior penetrations, precast steps, garage and man door brick moulding and roof wall intersections to maintain the shingle lap process.

Windows are installed by the framers with a specific building envelope detail to provide a drainage plane at the bottom of the window. Then, just before siding, Cedarglen requires that all windows are sealed with a combination of Envelope Seal and weather resistant membrane that seals the window to the wall and directs all water away from the opening. However the basement windows are addressed differently. The basement wood rough opening and the window will be sealed with Envelope Seal on all four sides and finished with parging. Also before siding, all doors are set by Cedarglen staff and sealed at the bottom plate with a specific detail to prevent water from penetrating into the home.

Our job at Cedarglen is to inspect each of our contractor’s details to ensure that all the building envelope processes are followed. Ensuring and implementing all these details during the build of your home, will leave you with a product that will outperform and outlast the competition.