22 March 2017

Well OK, it is not really an attic but it is the space above the ceiling and below the roof and the reason that it is supposed to be vented is that ideally the temperature of this space should be the same as the outside air. That way snow in the winter does not melt on your roof and freeze into ice which will damage the shingles...which is a bad thing. To accomplish this there are ridge vents at the ridgeline at the top of the roof and soffit vents on the underside of the soffit, the overhang of the roof.

Since finishing up the wiring I have begun to insulate the ceiling but have run into a problem. The 12" ceiling insulation closes off the area that allows air from the soffit vents to circulate into the attic space. This would mean that all that venting would be for just for show and the attic space would not actually be vented.

This is peering down into the soffit to the vent-before insulation.

and here is a picture of area with 12" of ceiling insulation blocking off any air movement between the soffit and the ridge vent.

What to do? What to do? So my solution to the problem was to procure 4" PVC sewer pipe and cut it into 2ft lengths and insert them between the soffit and the space above the ceiling therefore allowing air to circulate and the vents to do their jobs.

I'm not sure what "real" house builders do to solve this issue but this seems to me to aworkable solution that at the same time allows me to insulate to the outside edge of the house and ensuring that I have insulated the place where the wall connects to the roof. A particularly problematic space as that area in a house in cold country (where the wall connects to the ceiling) can easily get cold and cause water vapor to condense and black mold to form....and that is a bad thing, even disregarding that fact that is is a place where heat leaks out of your house.

Building a house yourself is full of interesting problems like this that you never thought about before....