Ventilation suggestion


#1

I have two pictures to describe my situation. In the first picture (attached)

, you can see how the roof is pitched. The lack of ventilation between the rafters has caused damage to the inside of the house near the windows. Since there is no overhang to the roof where soffits would exist on the underside, I’m thinking of installing louvered vents on vertical exterior wall. In the second picture, I’ve added red circles where I intend to install vents. I have removed the aluminum capping in one section to expose the wood behind it. I would run the vents along the entire length of the exterior, at what interval, I’m not sure. Between every rafter? Every other rafter?

Here are the vents on your site that caught my eye. I’m not sure if 1/5" is large enough although the exposed wood area in the one picture is roughly 9" high and you’d expect the bottom portion of that to have insulation.

Thoughts?


#2

Given there is sufficient overhang button vents would possibly help. You will need to keep the as close to the bottom of the roof as possible to prevent leaks. The link you posted is for 1" vents, they arnt likely to give you much ventilation at all. If you are going to go to the effort I would do 3 or 4"’.

Another option would be to remove the top few courses of shingles cut a strip out and install smart vent, then replace or reinstall the shingles. Typically for proper ventilation you would want a vent at both the top and the the bottom of the section, but I would not mess with the gusset.


#3

You need to have intake and exhaust vents on most shingle roofs, and it doesn’t look like there will be any intake vents. Also lack of ventilation normally doesn’t cause damage, it just reduces the lifespan of the shingles. I would look at installing deck vents at the bottom of the roof for intake if you really think it is caused by lack of ventilation. You can also find calculators online which tell you how much you need for different types of vents. If the rafters are not enclosed you shouldn’t need a vent between every rafter.


#4

What about a product like this near the bottom and top of the pitched roof?


#5

Thinning about it more, I don’t think I can have any intake on the roof. At the bottom of the roof, is a channel/valley where a mirrored pitched roof also runs down to. Snow build up in the winter could get in an intake vent?

Given that hot air rises, would exhaust vents at the top of the roof be sufficient?


#6

That is the type ofproduct I was referring to. You could easily add then at the top, you would need to be very careful at the bottom, the low slope membrane in your valley/gusset should run up a few feet under the shingles you do not want to mess with it, also you do not want vents being burried under snow depending where geographically you are located.


#7

You need to quit thinking about ventilation and start thinking about waterproofing.

Sometimes you need to just accept that there isn’t going to be any meaningful airflow to provide ventilation.