Can I Overvent Soffits
#1
Member
Thread Starter
Can I Overvent Soffits
Is it possible to overvent soffits in my home?
When I go into the attic, I see almost no daylight around the eaves. Since I'll be getting my roof re-shingled, I'd like to install air chutes under the roof deck to ensure that the insulation is kept away from the roof deck to allow my soffit ventilation to be effective.
Q: So should I be installing the air chutes between every pair of roof rafters? Or is that too much soffit ventilation? Currently I have five gable vents and four box vents in a one-story house with about 1800 square feet plus double-detached garage.
Thanks.
Wayne
When I go into the attic, I see almost no daylight around the eaves. Since I'll be getting my roof re-shingled, I'd like to install air chutes under the roof deck to ensure that the insulation is kept away from the roof deck to allow my soffit ventilation to be effective.
Q: So should I be installing the air chutes between every pair of roof rafters? Or is that too much soffit ventilation? Currently I have five gable vents and four box vents in a one-story house with about 1800 square feet plus double-detached garage.
Thanks.
Wayne
#2
Group Moderator
Are your soffits vented? Roof shingling has nothing to do with anything inside your attic so you don't need to wait for the roofing. Insulation dams are usually installed on every bay to prevent the insulation from blocking the air path.
#3
Member
Thread Starter
Yes the soffits are vented. (Aluminum soffits with ventilation holes, no wooden soffits behind the aluminum.)
I'm interested in doing this at the time the roof is replaced because after the old shingles are removed (and before the new installed), we can remove the plywood for easy access to the bays to install the air chutes. If I try to do it at another time, I have to figure out how to get to the eaves from within the attic without screwing up the attic insulation.
Thanks.
Wayne
I'm interested in doing this at the time the roof is replaced because after the old shingles are removed (and before the new installed), we can remove the plywood for easy access to the bays to install the air chutes. If I try to do it at another time, I have to figure out how to get to the eaves from within the attic without screwing up the attic insulation.
Thanks.
Wayne
#4
Group Moderator
You are going to strip off the roof sheeting all the way along your roof edge to install insulation baffles??? That will have a significant affect on the cost of your new roof.
#5
Hi, I have been told by roofers that if you have soffit vents then you shouldn’t have gable vents but instead there should be a ridge vent, I had serious mold problems at one point.
do you have blown in insulation now?
Geo
do you have blown in insulation now?
Geo
#6
Member
Thread Starter
That will have a significant affect on the cost of your new roof.
I was told to remove the roof plywood at the eaves, nail a 1x2 strip of board to each side of each bay, then staple a styrofoam air chute to the 1x2's to keep the insulation back from the underside of the roof deck. That doesn't really sound like a lot of work, although I'll admit that it could add $1000 or more to the cost. But I don't see how attempting it from within the attic will be easier/cheaper. Or am I missing something?
Actually, I'd prefer to do it myself from within the attic. If done when the roof is done, I pretty much have to get the roofers to do it, since they're not going to wait for me to do the baffle work before they proceed with the shingling. I've thought about removing the lower level of shingles and sheeting myself and doing the baffle work a day or two before the roofers come, but there's some risk there if we get rain, obviously.
The extra cost was part of what motivated my original question re whether I'd be overventing the soffits if I put baffling into every bay. I don't want overkill, but I do think I need to fix my soffit ventilation.
Ventilation expert Joseph Lstiburek says to aim for 60% ventilation at the soffits and 40% in the ridge or roof vents. If I baffle every roof bay at the eaves, I suspect I'll end up with a lot more than 60% at the soffits.
#7
Forum Topic Moderator
The soffit vents are the intake, the ridge or gable vents are where it exhausts. The soffit vents let cooler air in and forces the hotter air out the ridge/gable.
I don't think the insulation will be a big deal, just fluff it back up on your way out.
I don't think the insulation will be a big deal, just fluff it back up on your way out.
#8
Member
Thread Starter
I have been told by roofers that if you have soffit vents then you shouldn’t have gable vents but instead there should be a ridge vent
I had serious mold problems at one point.
Do you have blown in insulation now?
#9
Member
Thread Starter
just fluff it back up on your way out
I suppose I could use a rake to move it aside, but I'm not sure how well that would work.
#11
Member
You do not see any evidence of mold in the attic so I would leave well enough alone.
Perhaps just add a couple/few roof vents.
Once blown in insulation is compressed it can be difficult if not impossible to get it fluffed up again.
This depends on the type of insulation.
You see some staining in one corner but that is likely due to a leak.
Perhaps just add a couple/few roof vents.
Once blown in insulation is compressed it can be difficult if not impossible to get it fluffed up again.
This depends on the type of insulation.
You see some staining in one corner but that is likely due to a leak.
whdyck
voted this post useful.
#12
Member
Thread Starter
You see some staining in one corner but that is likely due to a leak.
I might need the roofers to replace that corner of the roof deck, at which time they could add a few air chutes to increase air flow there too. Apart from that, yeah, maybe just add a few more roof vents.
#13
Member
Installing the baffles from the inside is the proper way. You could do it yourself and likely have the entire attic reinsulated with blown-in for less than $1,000 (not sure what your square footage is).