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Is cinderblock a good insulator?

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t.ruckus.rex

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I'm going to go look at some shop space for rent tomorrow.

The owner said it was unfaced cinderblock.

I'm wondering how good of an insulator is it
 
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Steevo

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Just plain old cinderblock walls with nothing inside them are probably so low on the R-value scale as to have no insulating effect at all other than as a wind block.
 
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Ironcrow

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An 8 inch block wall has about the same R value as a single sheet of 5/8 inch plywood. So, yes, nearly nothing.
 
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RedBKM

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RustCollector said:
CMU block has good thermal mass.Once its warm inside the building,itshould stay warm,and stay cool once cooled.
Click to expand...

My shop is uninsulated block and it doesn't get hot until lunchtime in the summer. Obviously, it doesn't get warm until lunchtime in the winter! If I burn the wood stove during the night its OK.

What is the ceiling? Are you going to be heating/cooling the whole place?
 
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Kevin54

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A block garage in the winter is cold unless you have some good heat. A block garage in the summer is cooler than a standard garage. But unless painted with a good penetrating waterproof paint on the outside, you will have moisture problems. Sealed good on the outside, you shouldn't have moisture problems. The air inside the cores will act as somewhat of an insulator, although not much. But if you live in a cold zone, and have sun warming the block, the trapped air does help.

Ideally, you want a stud wall inside, insulated, and covered in the material of your choice.
 
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Architorture

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the air in the cores would only be beneficial if it couldn't circulate...so that means the cores would have to be narrower than approximately 4" and the cores at the top of the wall would have to be sealed...if we are talking an 8" block wall there is a good chance that neither of these conditions exist.

assume an R-Value somewhere between 1.0-2.0 depending on the density of the concrete in the blocks...so yeah, a well sealed sheet of plywood would perform about as well.
 
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t.ruckus.rex

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I'll take a look at it tomorrow.

I havent seen any pictures inside just replied to an add. I think the only way to heat is electric but I'll see tomorrow.
 
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hoho98925

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Almost no insulating value. I've seen some blocks that the hollow cores had been filled with vermiculite, don't really think that did much good.
 
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Hawk

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Back in the early 60's down on the Carolina's coast there was a lot of talk of building cinderblock homes.The plans always called for the walls to be filled with sand for insulation. Can't say I was ever interested in one for living in.
 
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chruler

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Thermal lag will always be a factor unless you create some air space between the wall and the room, like, a conventional insulated wall. Otherwise you'll constantly be trying to heat or cool the cinder blocks.
 
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LB-1911

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t.ruckus.rex said:
I'm going to go look at some shop space for rent tomorrow.

The owner said it was unfaced cinderblock.

I'm wondering how good of an insulator is it
Click to expand...

t.ruckus.rex said:
I'll take a look at it tomorrow.

I havent seen any pictures inside just replied to an add. I think the only way to heat is electric but I'll see tomorrow.
Click to expand...


Here is another link with a few numbers, None of which look good.
http://northfieldblock.com/architectural-masonry-2/hand-crafted/r-value/

You may want to research the kilowatt hr rate for the Denver area.

Good Luck
:beer:

Farmall450 said:
It traps air so decent.
Click to expand...
"decent"? :headscrat
An 8" hollow concrete block (the type used for most concrete block walls) only has an R-Value of 1.11.

http://www.universalconstructionfoa..._9i92kek4cr08JHlGXHEITu-_rsndJGnVyBoCCNjw_wcB
 
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CNGsaves

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OP . . . . WHERE are you located ?? Trying to heat "cinderblock" shop in Fort Lauderdale, FL would be vastly different than Chicago or Canada !! :D

Update GJ Profile with City / State / Country.

Effectively you'll be heating the outside, so make sure you have plenty of Btu as you'll need it !! ;)
 
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LB-1911

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Last edited:
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NUTTSGT

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LB-1911 said:
Here is another link with a few numbers, None of which look good.
http://northfieldblock.com/architectural-masonry-2/hand-crafted/r-value/

An 8" hollow concrete block (the type used for most concrete block walls) only has an R-Value of 1.11.

http://www.universalconstructionfoa..._9i92kek4cr08JHlGXHEITu-_rsndJGnVyBoCCNjw_wcB
Click to expand...


The first link you posted had a 2+ R-value and the last one matched my link of 1.11. Even going with the higher doubled value, the insulation factor of a CMU is horrible. It's not much more than a windbreak.

The back wall of my garage is concrete block and I heat with wood. When it was a bare wall, I stoked the woodburner to it would barely get to 70 degrees. That back wall was always cold to the touch. Once I put 1.5" of styrofoam and 7/16" OSB on the walls, I could easily get and maintain the 70°. After siding the the outside, using firring strips, 3/4" styrofoam, 7/16" OSB and vinyl siding, the garage heats nicely along with a few other mods.

That bare block wall will always be a heat sink, sucking any heat you create out of the inside. It will need to be covered somehow or you will be throwing your hard earned heating dollars away. Even if you are renting and living in an area (editing your profile helps us, help you) that gets cold in the winter, you might be ahead to foot the bill to insulate and cover the wall.


EDIT
LB-1911 said:
I'll wag it - Denver Co -
Click to expand...

Oh yeah, if that's correct, that's going to be one cold *** mile high CMU.
 
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chops101

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My CBS walls do a great job of keeping heat out. They are wrapped exterior and interior though.
 
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chops101

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The exterior is wrapped in 5/8" type closed foam sheet insulation ( I only have construction pictures to go by, not original owner), the interior walls I'm familiar with, it is a paper faced thin insulation that fits between furring strips. When replacing some sheetrock I replaced the interior insulation with double reflective insulation (Reflectix from HD). During tests on this wall that had afternoon sun, it was night and day temperature delta from the bare block (warm) vs Reflectix faced block (cool).
 
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PCO6

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My garage is made of cinder block with an exterior brick veneer. I strapped the inside with 2"x3" 's and insulated the walls with 1.5" rigid foam with a 7.5 R value. I then added a vapour barrier and covered the walls with drywall. More insulation and less strapping would have been better but I have no problems with heat now. :D

View media item 39097
 
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kf4zht

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Calhoun, GA
A family member lived in a cinder block house for a while as a renter. Spent a fortune in the winter, he could have afforded a more expensive place with better insulation by the time he was done.
 
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t.ruckus.rex

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I'm right by the mountains.

Cinderblock or not the place was in a spot that said rob me :(

so no go
 
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