Foundation heat loss and insulation.

[twd000]

I googled some payback numbers and found this chat from a federal study. Didn't realize the payback numbers are this high especially considering the fuel was natural gas in the study. I would imagine much larger savings with propane or oil. I bought 10 sheets at $34 each so I will recoup my cost in 1 winter.
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that's kind of a silly set of assumptions for a comparison. Most people with un-insulated basement walls don't use it as conditioned space. Does anyone actual run gas furnace ducts into a basement with bare concrete walls?

My basement is un-conditioned but already about 3/4 finished with some fiberglass batts and drywall. The 1/4 un-conditioned section gets pretty cold, but that's where I lager my homebrew!

 

[Brian26]

that's kind of a silly set of assumptions for a comparison. Most people with un-insulated basement walls don't use it as conditioned space. Does anyone actual run gas furnace ducts into a basement with bare concrete walls?

My basement is un-conditioned but already about 3/4 finished with some fiberglass batts and drywall. The 1/4 un-conditioned section gets pretty cold, but that's where I lager my homebrew!

Its the 2nd law of thermodynamics that heat flows from hot to cold. The basement is usually one of the coldest spots in the house. Massive amounts of heat flow through your floor into your basement and right out your house. Your thinking since heat rises its all going out your attic/roof but your actually losing more heat through walls/flooors and the basement then the attic.

 

[twd000]

Its the 2nd law of thermodynamics that heat flows from hot to cold. The basement is usually one of the coldest spots in the house. Massive amounts of heat flow through your floor into your basement and right out your house. Your thinking since heat rises its all going out your attic/roof but your actually losing more heat through walls/flooors and the basement then the attic.

I'm not sure I'm following you. Indeed, heat rises by convection from basement to attic. Heat also conducts sideways from the basement to the ground outside. Whether the amount of heat loss is greater from the basement or the attic, depends on the specific basement and attic in question, how well sealed and insulated they already are. I don't doubt that your house will lose less heat than it did before you foamed the walls. But the portion of your basement wall below the frost line has a boundary temperature of 55F, which doesn't suck away nearly as much heat as the exterior boundary temperature of 20F, or 0F on the remaining walls & attic, etc.

 

[Brian26]

Finally got the spray foam done on the foundation sill plate. I got the 2 tank dow frothpak from lowes. Its my first time using this stuff and its really amazing product. So easy to spray and completely airseals and is r6 inch.

Its going to drop into the teens tonight so it will be interesting to see how it performs with the flir.

 

[laynes69]

Finally got the spray foam done on the foundation sill plate. I got the 2 tank dow frothpak from lowes. Its my first time using this stuff and its really amazing product. So easy to spray and completely airseals and is r6 inch.

Its going to drop into the teens tonight so it will be interesting to see how it performs with the flir.

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Any updates on the improvements?

 

[Brian26]

Any updates on the improvements?

Its been a massive amount of work but I have all the insulation in and I am installing the drywall now. Was definitely worth it. The basement temps are significantly higher and are mostly around 60 degrees now. The most noticeable difference is how much warmer the floor above is now.

Here are some FLIR shots with just the insulation up. You can still see the heat loss soaking down through the floors and upper basement walls. Good visual of how heat will also travel down through colder floors. I might experiment with a section of basement ceiling with some mineral wool and see what it does.

Has anyone insulated a basement ceiling?

 

[peakbagger]

Those froth packs are great except I feel guilty with all the stuff I end up throwing away at the end. I wish they could come up with a system that generates less trash.

 

[laynes69]

Its been a massive amount of work but I have all the insulation in and I am installing the drywall now. Was definitely worth it. The basement temps are significantly higher and are mostly around 60 degrees now. The most noticeable difference is how much warmer the floor above is now.

Here are some FLIR shots with just the insulation up. You can still see the heat loss soaking down through the floors and upper basement walls. Good visual of how heat will also travel down through colder floors. I might experiment with a section of basement ceiling with some mineral wool and see what it does.

Has anyone insulated a basement ceiling?View attachment 254207View attachment 254208View attachment 254209

Very nice! Every little gap and crack all adds up as well as missing insulation. I'm in the process of adding a second bathroom upstairs and I just finished drywall from a gut job directly down below. Everything that I've sealed and insulated has made a huge improvement on the house. While I need to foam the sills in our basement, at this point I just have alot more to do to finish the new bathroom. Eventually I'll get there!

 

[begreen]

The basement temps are significantly higher and are mostly around 60 degrees now. The most noticeable difference is how much warmer the floor above is now.

That's exactly what I noticed when I turned our crawlspace into an insulated, conditioned space.

 

[Seasoned Oak]

Has anyone insulated a basement ceiling?

The only reason to heat a basement ceiling is if the basement is kept colder than the 1st floor. My friend was building a ranch house and was going to insulated the basement ceiling .Since he was also going to put a woodstove in the basement i explained insulating his basement ceiling would be counter productive by stopping the heat from warming his upstairs floors.

 

[Brian26]

Its been pretty mild here but we finally got some real cold. Its 11 degrees out and I just went out with the FLIR. I think I am going to go R20 and add another 2 inches of foamboard. My unfinished basement with no heat source has stayed around 50-55 all night which has been a massive improvement. It would drop to the 40s with similar temps before the insulation.

This FLIR shot still shows foundation temps in the mid 30's. Though that could be ground temps soaking in?

I have r20+ in the walls and the FLIR shows it as outside air temps when measured off the siding.

I am going to add another 2 inches of foamboard and will report back.

 

[Seasoned Oak]

I was putting up board foam today and the wall temp was the same as the room temp .Uninsulated walls were 10 to 20 degrees colder then room temp.

 

[Brian26]

I went outside this morning and shot the foundation again. I read a research paper that suggests the foundation actually wicks heat from the ground and that is what I was seeing. Its been pretty mild here and it makes sense as soil temperatures were still quite high.

Foundation was 17 this morning. All I can say is insulate your foundation if its not as the results have been beyond impressive.

 

[Seasoned Oak]

Looks like your house is very well insulated with heat only escaping from windows and doors which can be expected.

 

[begreen]

How are the heat pumps doing at 6º @Brian26 ?