Basement ceiling insulation needed? Conditioned space
Last Post 12 Dec 2013 12:08 PM by jonr. 8 Replies.
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rk05User is Offline
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11 Dec 2013 11:02 AM
I was wondering if I added insulation to the ceiling of a basement room if that would help the room above get any warmer? The room is on a walkout ranch with two exposed walls that have been insulated with 2" closed cell foam already. There is also a vent for the room so it is a conditioned space.

I'm sure more of my problem is with the HVAC but if adding insulation to the ceiling would help the room above I can do it now before I finish my drop ceiling.

Thanks
Bob IUser is Offline
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11 Dec 2013 11:15 AM
The first step is to find out where the cold air is coming from. It is often a matter of airsealing, not insulating. If you are heating your basement room to a comfortable temperature, the floor should be at least that warm. A few questions:
Is the basement ceiling exposed or drywalled?
Are the unexposed walls insulated? (if so, how?) Is the unexposed foundation walls accessible?
Has the basement sill/foundation and sill/sheathing joint been airsealed? (This can be a huge air leak and when finally sealed in my house, instantly raised the temperature of the floors above)
Bob Irving<br>RH Irving Homebuilders<br>Certified Passive House Consultant
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11 Dec 2013 12:32 PM
The whole basement was just insulated this spring with 2" of Closed Cell foam from floor to ceiling including the rim joist. I noticed the effects right away in our summer cooling. I actually have two of the four HVAC ducts shut off since the room stays very close to 70F. This room still has its duct fully open but the room is about 67F.

This section of the house is the walkout and is totally exposed poured foundation.

The ceiling is currently exposed but I have started installing a drop ceiling. I stopped putting up the rest of the grid in case I was to install insulation in the joist.

I have some left over Roxul I used in the walls to keep the sound down (this is a laundry room) that I thought about using in the ceiling above to help with both sound and insulating.
Bob IUser is Offline
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11 Dec 2013 01:12 PM
So you have a lower level room at 67F, and the rooms above are also heated to about that temperature but still feel cold? Sounds to me like you have some infiltration/exfiltration going on. If that's the case you should have a blower door test and possibly a fog test done to locate the source of the cold air. Maybe air leakage into the attic?




Bob Irving<br>RH Irving Homebuilders<br>Certified Passive House Consultant
rk05User is Offline
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11 Dec 2013 03:33 PM
The first floor is heated to 70F and stays at that temp with the exception of the bedrooms which are all over the finished basement. This room above the laundry room is the worst as far as temp off from the Tstat (-6F). I already know that I need some air balancing done to help get the rooms more equal to the rest of the house, I just wasn't sure if adding any insulation to the ceiling would be any noticeable difference.

From reading different web pages it sounds as if adding insulation to the ceiling of a "conditioned" space wouldn't help the area above, if anything maybe cause troubles for the room below.

I need to get this ceiling finished so I think I will be skipping adding insulation to this rooms ceiling. If I do anything I may add whatever amount of Roxul to the perimeter of this room to help with sound and possibly any draft that may still be occurring.
Bob IUser is Offline
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11 Dec 2013 03:46 PM
"help with sound and possibly any draft that may still be occurring"
insulation will not stop drafts. Why not deal directly with stopping the drafts?
Bob Irving<br>RH Irving Homebuilders<br>Certified Passive House Consultant
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11 Dec 2013 09:56 PM
Laundry room??

Check the back draft from the dryer vent.
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12 Dec 2013 09:14 AM
There are two drafts that I found, one is where I have a new electric line running outside after I had the spray foam installed and the other is around the door. I can seal up both but I would think the leak would have to be bigger than what they are for the temperature difference we are seeing in the room above.

Again, I think I have more of an issue with duct balancing than air infiltration. I will see what I can do about stopping ALL the air leaks but it doesn't seem that putting insulation in the basement ceiling will make any noticeable difference unless the room was not a conditioned space.
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12 Dec 2013 12:08 PM
Agreed, you normally do not want insulation between conditioned areas. Noise or adjusting radiant floor heat flow direction are exceptions.
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