The house is 26×30 with an attached garage of 24×24.
It is T shaped with the house part being the top of the T.
It is basically two gable roofs. However the right hand side of the T there is a shed roof ending at clearstory wall.
I had the facia board off the shed roof to do some wiring and was able to verify it’s construction. There are not vent shoots. But the vaulted ceiling does have a poly vapor barrier and there is only one penatration and the is about 1″ hole for the wire.
It has a couple of soffit vents, but of course those only communicate with a couple of rafter bays. And the rafter bays are tight with FG insulation. And there is no deliberate venting at the top end. But it was poorly detailed and there are gaps between the facia and the soffit. And there where no signs of any kind of condensation.
So between the back that I the ceiling is well sealed and that there is a some very slight opening if a view drops of water get in for it to escape I don’t see any need to try and change the ventilation on that part.
Currently the rest of the house is vent with a turbine vent at the intersection of the to gables and gable end vents at the top left of the T and the bottom of the T.
The best that I can estimate of the sizes there is just enough venting on the roof based on the 150/300 formula.
But while I have not gotten up on the ladder to check measure the size of the soffit vents or pull some to see if they have full size opening behind them or just a couple of holes it appears that there is not enough soffit venting.
Also when I run my whole house fan, which the best that I can find on the web the venting should be enough if I have to total amount of venting for the size of the attic, I can feel the air coming out the gable end vent on the garage in the driveway about 12ft away.
Also there is not any sign of condensation problems in the attic, however it does get hotter than I would like. But I also realize unless I made the roof into a open picnic shelter type of roof that you can’t really “cool” an attic with venting.
But anyway I thought that I would replace the turbine and cover the gable end vents and install ridge vents as part of a reroof. And add more soffit vents.
I looked at airvents data and they had a couple of models that had 9 sq in of net free air space per running foot. Basic on that my ridges would give me just the minimum amount of venting. But most of their models have much more venting.
A) do you think that worth making the changes? In either case I would want to check and probably increase soffit venting.
B) I just picked airvents as they had are the first site that I found that had the best info and they also make soffit and gable vents so I could get the data on those.
But I have no idea of baffled or unbaffled. Most like use the brand(s) that the roof normally uses.
Location in Kansas City Mo area. Limited amount of snow. But tornadoes. Don’t expect any live through those. But that also means looks of hail and hard blowing rain.
William the Geezer, the sequel to Billy the Kid – Shoe
Replies
Bump.
William the Geezer, the sequel to Billy the Kid - Shoe
Bill -
I don't like turbines for a variety of reasons and am partial to ridge vent. I'd probably go with your plan.
http://www.quittintime.com/ View Image