Comments on: Adding Soffit Vents

By: Craig B

Craig B — Thu, 07 Jan 2010 00:12:19 +0000

Randy,
I want to install attic baffles before blowing in insulation. The area I need to install baffles the roof trusses and joists are at almost a 30 angle from each other (below this area is cathedral ceiling. There’s no way I can get down to the soffit from the attic to install the baffles. Is there any way to remove the soffit (outside) and somehow slide the baffles in from there? Is there something else that could be done? Thanks, Craig

By: Ben Erickson

Ben Erickson — Mon, 12 Oct 2009 13:19:16 +0000

Randy,
Sounds like you’re doing everything right as far as energy efficiency goes. The problem with blocking the vents in your attic during the winter is that it might cause moisture to build up in the attic which could lead to mold and rot.

By: Randy

Randy — Sat, 10 Oct 2009 22:35:10 +0000

Thanks for your reply Ben. I should have stated that the attic has an origianal r13 layer then I added a r30 layer a few years ago. furnace is 92% efficient installed in 1998 and all the windows have been replaced within the last two years. We do have a whole house attic fan that gets covered in the winter time. It seems the more I try to be efficient the higher the bills go.

By: Ben Erickson

Ben Erickson — Fri, 09 Oct 2009 12:56:59 +0000

Hi Randy,
Good point about fire and attic vents, thanks.
I wouldn’t think that too much attic ventilation is the problem. More likely the culprits are not enough insulation in the attic, doors and windows that aren’t energy efficient, not enough insulation on the HVAC ductwork (if it runs in the attic), or an undersized HVAC system. Plus, you do live in Michigan where it gets pretty darn cold in the winter!

By: Randy

Randy — Thu, 08 Oct 2009 16:45:52 +0000

I have a 1700 sqft ranch, when the roof was redone aprox. 10 years ago, we had a continous ridge vent installed, the 3 foot deep plywood soffits were removed and a continous vented vinyl soffit was installed the entire length of bothe the north and south sides,there are also 2 gable vents on opposite ends east & west sides each 2′H x 14″W. we have over the years had difficulty keep the house warm during the cold michigan winters. and have experienced outrageous energy bills. during the summer months we notice that the house also seems to go through a heat soak in the evenings that overwelms the air conditioned living space. Is it possible that too much ventilation could be causing incresed energy use, and causing erradic temperture fluctations. Oh I might add that on windy days it is impossible to keep any heat. The house always feels cold even when it is warm outside.

Also in response to an earilier post about vents above windows and doors, I was told that this should not be done, because in the unlikely event that a fire should occur the air currents would draw the flames into the attic causing more damage.

By: fran ashton

fran ashton — Mon, 07 Sep 2009 16:45:42 +0000

Never mind – I see it now –

Kevin Says:
January 24th, 2009 at 2:42 pm
Is there an answer to B. hanson 11/8/07 re: how many baffle vents per soffit?

Your calc’s for # of required soffits is very helpful. Wondering if baffles are needed between all rafters or only those rafters over soffits.

Install soffits on ends and in middle for best results? Ie: need or 3 for 13 rafters.

Thank you.

Ben Erickson Says:
January 26th, 2009 at 9:38 am
Kevin,
Baffles are only needed in the rafter/joist spaces where soffit vents are located. If you have continuous soffit vents, install baffles in enough (or all) the spaces to give you the needed square footage of vent area. Space the soffit vents out so they divide the attic area into equal areas. In your case, I would put one in the center, then come in a couple of rafters on each end for the other two.

By: fran ashton

fran ashton — Mon, 07 Sep 2009 16:40:58 +0000

I hate to repeat someone else’s question, but I cant seem to find or access the answer from B. Hanson’s question on
November 8th, 2007 at 1:19 pm (AND I need the same answer)
I am ready to do this plus add styrofoam ventilation channels. I am wondering if the ventilation channels go only where the soffit vents are or must I do all the roof rafters with the channel vents?

By: John

John — Sat, 29 Aug 2009 05:05:27 +0000

When I did research on this I focused on net free area. I wonder why this article fails to mention net free. Based on your Danny’s example of using vent size alone, you will not let enough air in since the grills/screen take up space. An 6*12 soffit vent is not really 72 sq.” of ventilation but is only 27sq.” of net free area. This can make a big if you put in 10 vents but really need 30 vents. I am not a professional but would it makes more sense to me…

By: marc laplante

marc laplante — Sun, 23 Aug 2009 16:11:58 +0000

I have a seasonal unheated cottege with a vaulted ceiling-the roof pitch is @5in 12(10″eaves)-at present there is no venting at all. I want to know if 1 gable vent on the back wall as high up as I can install it would be enough for this 400 sq.ft. building built on blocks

By: debbie

debbie — Sat, 08 Aug 2009 21:19:22 +0000

hi, 16 yr old house. 7 roof vents, soffit vents all around. notice shingles curling above 1 room. attic is very hot.. how do i check to see if my roof and soffit vents are plugged? have had strong wind storms in past, one time attic trap was sucked up into opening. could this have disturbed the insulation in attic enough to cause plugged vents.?