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Insulating soffit overhang?

25K views 17 replies 9 participants last post by  Gary in WA 
#1 ·
i live in a 1958 built split level ranch in Nassau County, New York. On the west side 1st floor of the house I have a gargae, laundry room and a bathroom sitting on a concrete slab. On top of the 1st floor directly over the garage are two bedrooms and 1 bath. In the rear of the house there is what I believe is called a cantilever overhang. The rear bedroom and bath extends and overhangs past the 1st floor of the house approximately 2 feet. In the front of the house there is a soffit overhang that is covered with shingle roof. This overhang extends from the front of the garage about 3 feet and then goes up 1/4 of the height of the wall of the second floor front bedroom. The problem that I'm having is that the floor in both bedrooms and bathroom are freezing cold in the winter time. What would be my options for insulating those two spaces.
 
#4 ·
I recently ripped out the portion of sheetrock just to see how I could better insulate the front area. The garage ceiling had some old insulation with sheetrock. The floors were freezing. It appearred that the cold air was was coming in from the soffit and running above the insulation in the garage and also running up the front facing bedroom wall. The hardwood floor and front facing wall are freezing. Also in the rear of the house the floor of my rear bedroom and bathroom are also freeezing cold.

I was thinking of spray foam?
 
#6 ·
spray foam will give the best r value for the confined space. there is also an attic crawlspace above where you tore down the drywall, you can see the T&G flooring and there should be an access to get in there. you will need to insulate the walls where that attic meets the bedroom walls also. so insulate the overhang from below and then insulate from inside the attic space...
 
#9 ·
ok, kind of hard to get (one picture) from all of the pics. the part I'm seeing that overhangs the house, the third pic looks like it has an attic, does it? is there a wall soffit vent at the top of that roof where it meets the house?

^ Exactly Joe, what I was wondering too
 
#10 ·
Looks like a poor design but that's what I was also thinking. There is 1/4 inch plywood under ther vented soffit material with no vent holes that's I know of in the plywood. There is still a lot of cold air that is coming in from i gues the seams of the plywood. What I was wondering is could I totally seal off the entire area of the soffit so no cold air is seeping in and then have spray foam on the wall extending down from the bedroom and then to block off the space in joists that goes from the garage to the soffit. Sounds a little confusing but I just want to be sure that I should not be concerned with venting that area.
 
#14 ·
Yes , the floor is insulated but it is old and looks like its not doing much. I plan on tearing down the entire garage ceiling and insulation and having it all spray foamed. My main concern was the cold air that seems to be coming in from the soffitt its running up the exterior bedroom wall and through the wood floor. So I would need to toatally seal off or insulate that soffit area to prevent that cold air from coming in.
 
#15 ·
If it's really just the floors that get cold and there isn't any damp creeping in... I'd be more inclined to put down some rugs... Saves effort and money. If the problem is damp I'd probably just rip everything and start all over again. The suggestions above about putting in new plastic soffits is pretty stellar advice... but that's just my opinion, there are plenty of viable options.

As long as there's no damp and ambient temperature is all right I don't think it's that big of a problem. :)
 
#16 ·
really the exterior wall envelope and the outer portion of the floor below the exterior wall needs to be insulated only, there should be no need to insulate soffits because they are not lived in. getting access to the spots that need the insulation, or insulation upgrades is most likely the biggest issue...
 
#17 ·
So there is no insulation under that 2 foot "soffit overhang"? If not, then I think you should spray foam that at the same time that you have the garage ceiling done.
One more thing to check is that the entire wall of the bedroom is insulated -- don't assume anything.
 
#18 ·
For your location, -4" of closed-cell SPF is required in the floors; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_par002.htm

http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_sec002.htm

To stop air from getting to the front wall under the shed roof, you could go with an unvented design though it requires R-15 SPF against the roof sheathing to prevent condensation; http://www.buildingscience.com/docu.../irc-faq-conditioned-attics?searchterm=attic+ Otherwise it would be a bear to air seal. Check with local AHJ, you may need to cover it against ignition in the attic, or SPF on the front wall sheathing in the attic space. Maybe not, if completely sealed from exterior.

Personally, I would add rigid foamboard under the joists in the garage and at both soffits to stop the thermal bridging at joists and exterior ground radiation, fig.7; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/

1/2" would work at 33 cent per square foot, cover with 5/8" drywall, type-X per code for a garage with living space above; http://www.lowes.com/pd_101647-1722...rentURL=?Ns=p_product_avg_rating|1&facetInfo=

No plastic vapor barrier required in Zone 4--- "Class I or II vapor retarders are required on the interior side of frame walls in Zones 5, 6, 7, 8 and Marine 4. " From; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_6_sec001_par003.htm. Always check locally.

Gary
 
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