Hi y’all. I’ve been currently working a remodel on a two story house, measuring 28ft X 24ft. The roof is a 4 sided hip. Recently, I finished installing blown-in cellulose insulation into the exterior walls. This house has ABSOLUTELY no soffit overhang whatsoever. The rafter tails are cut flush with the rafter plate, and a 2X8 fascia board was attached. Directly underneath the fascia board, is a 1X8 frieze board. The frieze board butts up tight to the fascia, there is no kind of bed or corner moulding seperating the 2 pieces. The fascia board juts out approx1 inch from the frieze board underneath.
Due to no soffit, I noticed when insulating, that small diameter vent holes had been drilled into the stud wall cavities at various heights on all sides of the house structure. These holes had the plastic vent plugs inserted. Since the house had no previous insulation in the wall cavities, I suppose these vent holes allowed air to circulate up into the roof.
I’ve recently installed new roof shingles on this house. Prior to re-roofing, the roof contained no roof vents of any kind. The owner asked me to cut-in and install an electric power vent; which I have done, but have not been inside the attic yet to complete the wiring hook-up.
Sooo, now I have a way to force air out of the roof, but the blown-in insulation certainly makes the original vent holes useless.
What is best way to proceed? Since the walls originally had vent holes, which I’m assuming(?) allowed air travel up the wall cavity and into the attic, then I guess I could install ventilation by somehow venting via through the frieze board location? BTW, We stopped the blown-in insul just below the frieze board . I’m thinking maybe use a core-a-vent product or something along those lines. This house is also scheduled to recieve vinyl siding, with 1/4 inch fanfold insulation as a “backer” for the vinyl.
Soooo, any ideas or opinions?
Thanks.
Davo
Replies
This is a case where a blown dense pack of cellulose in the attic can eliminate the need for venting there.
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Piffin,
Attic joists are 2X8s, so if I blew in insul high enough to cover tops...would this be enough? Or must I insulate rafter bays as well?
Thanks.
Davo
I'd aim for 12"deep in this case. Mike Smith has more experience with situations like this. You could ask the insulation contractor too but my experience with some of those guys is that they don't know much building science. They know how to open a bag and blow it in. I think too much attic heat slows the brain cell functioning..
Excellence is its own reward!
I've seen people put 12"~ square vents in to accomplish this. They put one as low as possible near each corner, then put the same number up near the peak.
Doesn't look too hot, but does the trick.
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Boss,
It might work, but I agree with you that it certainly wouldn't look too good. Don't think the home owner would go for it.
But hey, thanks for the tip!
Davo
We have always vented hip roofs on the hips with a shingle over type vent. This seems to work (though how would you really know?) and also looks great. I think that it looks better than no vent, setting off the hip with a black line.
Assuming that you have a flat fascia, you should be able to work in some ventilation, either by cutting the top off and using drip edge that has a vent built into the drip portion of it, or by creating a thin vent space with blocks and a thinner fascia. You vents won't work very well without some openings at the eave.