# House colder after Spray Foam Insulation



## Windows on Wash (Aug 30, 2011)

Nothing.

Nothing about the rim joists being sealed should make the basement colder. 

Are you sure the vents in any of the duct work are in the same positions? 

The air may be more "static" now as a result of the reduction in loss from the poorly sealed bands which, in turn, could have slowed the movement of air into the basement...? Its a theory but most band joints allow for the air infiltration into the basement areas.


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## joecaption (Nov 30, 2011)

And how did you figure that?
Did you take the inside and outside temperatures before and after when the outside was the same temp.?


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## dlf622 (Jan 10, 2014)

I didn't take temps before or after.  .. I think the vents are in the same position. I'm not sure what you mean poorly sealed bands ... do you think the contractor did a bad job?


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## joecaption (Nov 30, 2011)

Not sure we would know without a few pictures.
The whole idea of an insulated basement ceiling is to close up the house envelope to reduce the heat loss inside the house.
Less heat going into the basement the colder the basement is.


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## dlf622 (Jan 10, 2014)

hmm .. sorry for my ignorance, but I would have thought that if the basement was warm prior to the insulation, it would even be warmer with the spray insulation. They only did the rim joists, the ceiling is not insulated.


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## Windows on Wash (Aug 30, 2011)

It should be. 

I can't see any reason, beyond a tighter structure allowing less conditioned air down there.


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## Gary in WA (Mar 11, 2009)

It is more than theory- but fact that rims allow air in/out; http://www.buildingscience.com/docu...joist/files/bscinfo_408_critical_seal_rev.pdf

http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/

Stands to reason, the new attic insulation is the culprit, not the rim insulation, IMHO. 
Did you check if they extended the soffit intake baffles above the new insulation? If not, any holes/chases from plumbing pipes from the basement are now supplying the starving exhaust vents with warmed basement air- as warm air rises through the basement floor- if they didn't check if air sealed previously. Were the basement top plates of interior walls air sealed, especially plumbing drain vent pipes that run to attic and beyond?

May want to check your ceiling drywall thickness/on center spacing; https://docs.google.com/viewer?a=v&...xf51fE&sig=AHIEtbQixCH3AO0RugCGh3VLQNBaXp54rA


Gary
PS. Welcome to the forums!


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## Tom Struble (Dec 29, 2008)

possibly your furnace is on less there by warming the basement less?Assuming thats where it is?


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## Windows on Wash (Aug 30, 2011)

Tom Struble said:


> possibly your furnace is on less there by warming the basement less?Assuming thats where it is?


Didn't think of that. That is certainly part of it. Even a completely sealed duct system, the radiant heat difference will have an impact.


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## Gary in WA (Mar 11, 2009)

Could be, Tom. Good thought!

Gary


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## michelclarke (Oct 26, 2013)

After using a spray Most damaging moisture within a building envelope cavity is the result of warm moist inside air being exchanged with the cold dry outside air within the walls. As the moisture in the air condenses, it forms dew within the insulation. Because foam insulation is an air seal, this moisture movement and condensation does not occur. It is ideal for use in climates where buildings are both heated and air conditioned because the situation is reversed in summer with moisture forming on the back of the interior vapor retarder.


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## Windows on Wash (Aug 30, 2011)

....hmmm...


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## michelclarke (Oct 26, 2013)

The best way to insulate the room would be to have it sprayed with closed cell insulation. That would provide a moisture barrier, seal any air leaks as well as provide insulation. Closed cell doesn't absorb moisture so mold isn't a problem and it has an R value of about 8 per inch! Having a professional do it wouldn't be cheap upfront but certainly would save you money in the long run. You can buy do it yourself kits but I'm not sure how easy they are.


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