Tags: Installations

3 Apr 2009, Comments Off

CFC Reviews CMHC Design Report: Window Installations – Flashings

Author: admin

Head flashings over windows are required where the vertical distance between the bottom of the eave (soffit) and the top of the trim is more than one quarter the width of the eave. Properly designed and installed flashings:

  • are continuous over the window,
  • extend to the adjacent wall cladding
  • must incorporate end dams
  • incorporate a 6% slope (after expected building shrinkage has taken place)
  • incorporate a drip edge that overhangs the element below (window) by 10 mm and projects beyond the face of the window by five mm.

Sill flashings incorporating end dams are also required to shed water away from the wall assembly below the window. Reviewed by Martin Lapedus.

3 Apr 2009, Comments Off

CFC Reviews CMHC Design Report: Window Installations – Shiplapping to shed water

Author: admin

Sheathing membranes, whether polymer or paper based, should be applied as shiplaps to direct water down and away from inner wall assembly. Sheathing membranes at the jamb should overlap the upstands of the impermeable membrane at the sill location.
At the head of the window, sheathing membranes should overlap window flanges and head flashings. Reviewed by Martin Lapedus.

3 Apr 2009, Comments Off

CFC Reviews CMHC Design Report: Window Installations – Number of glazing layers

Author: admin

Most building codes do not permit singleglazed windows in small (“Part 9”) buildings because of the potential for condensationrelated problems. The glazing options are therefore limited to a minimum of double glazing, with an IGU providing the most common form of glazing system.
An IGU can comprise many layers, although practical considerations limit the maximum to four. Multiple layers reduce heat loss not because of the additional glass (glass is in fact a good conductor of heat) but because of the additional layers of insulating air trapped by the glass. Double-glazed windows (two layers) are most common, but triple glazings are now more common in certain areas, such as Manitoba. A double-glazed window with a storm panel is effectively a triple-glazed system, and is usually treated as such.
Quadruple-glazed IGUs are rare, but becoming more common, especially with the introduction of thin plastic films instead of glass layers. A window with four layers of glass is heavy, and difficult to move, install and operate. On the other hand, a window with two glass layers and two films weighs about the same as a double-glazed window, yet provides the performance of quadruple glazing. Reviewed by Moishe Alexander.

Tags

AIR Alexander Building Canada Canadian Funding Corp. Canadian Funding Corporation CFC cmhc construction Design IDP integrated design Moishe Alexander performance report Reviews Window Window Installation
  •