Rafter vents

[noran01]

I am in the early stages of finishing up the 'nice to haves' for my garage (i.e. insulation & heat!!)....

I go out and purchase the plastic Provent rafter baffles and soffit baffles only to come home and discover they will not fit...so i had a couple of the cheap foam ones from Home Depot which fit just right...see below:

If i just block off between the top plate and soffit should that be fine? My concern is the baffle not covering the complete opening between rafters. I plan on using closed cell spray foam to insulate the ceiling when i am done. Thanks!

 

[kbs2244]

You have to have a clear air flow from the soffit vents into the attic space.

 

[noran01]

You have to have a clear air flow from the soffit vents into the attic space.

There is not attic here...its a typical a-frame style with small loft above (storage); hence the engineer beams you see in the picture. My issue/question is the following: is it ok to not have the vents be as wide as the rafter spacing (~14"). Due to the way the garage was framed (height restrictions) my engineered beams site atop my top plate which interferes with the 'Provent' baffles.

Its hard to explain, but hopefully you can make it out from the pictures.

 

[Steevo]

They do not have to be as wide as the space between rafters. They do need to have the ends open into the soffit area beyond the top of the wall, and to have the space around the baffle and the top of the wall blocked off to keep insulation from filling or blocking off the air flow from the soffit space up into the baffle, and into the attic space above.

In other words, I'd slide the baffle down a few more inches, and then make some cardboard pieces that fit between the side of the baffle and the rafter(s) where a gap exists that insulation can get into.

If you are spraying the underside of the roof, I do not understand the baffle at all.
They are for when your roof line is different than your ceiling line, and you will have insulation from ceiling line to some depth above that. The baffle allows soffit air to travel up into the uninsulated space above that. I don't see where that is in this setup?

 

[noran01]

They do not have to be as wide as the space between rafters. They do need to have the ends open into the soffit area beyond the top of the wall, and to have the space around the baffle and the top of the wall blocked off to keep insulation from filling or blocking off the air flow from the soffit space up into the baffle, and into the attic space above.

In other words, I'd slide the baffle down a few more inches, and then make some cardboard pieces that fit between the side of the baffle and the rafter(s) where a gap exists that insulation can get into.

If you are spraying the underside of the roof, I do not understand the baffle at all.
They are for when your roof line is different than your ceiling line, and you will have insulation from ceiling line to some depth above that. The baffle allows soffit air to travel up into the uninsulated space above that. I don't see where that is in this setup?

OK, thats what I wanted to confirm before I went back and got more of the cheap foam baffles. What a PITA...thanks!

 

[Jackson]

If you look on Durovents website you can actually see that they sell a different piece to attach to the top plate. Or you could just use a piece of styrofoam. But yes, it does have to take the venting up and into the rafter vents.

http://adoproducts.com/as_durovent-baffle

You can see in the middle of each piece (even the pink ones) a dotted line to cut on. That's for 16" centres, and gives you one vent per 16"o/c space. That's actually what they were designed to do, so if you did that by accident you nailed it!

Having said all that, for some reason I THOUGHT if you used closed cell spray you don't require venting. I'd call a sprayer and ask, maybe save yourself some hassle and $$. Or maybe not, but I'd check first.

 

[kbs2244]

Whatever you call it, the air space above the ceiling has to be vented from the soffits up to the ridge vents.
So, your foam baffles have to go down to the air space above the soffit vents and extend up enough to clear any above the celing insulation.