ABOUT CMUs
A tried-and-true system
Concrete masonry units (CMUs) are the standard hollow concrete blocks; the product has been around for more than a century. CMU use is more common in the southeastern U.S. than in cold-weather regions. CMUs are resistant to fire and insects, and, with adequate steel reinforcement, also offer high wind resistance. Walls can be insulated on the inside or the outside.
Fluffier concrete
An only slightly younger cousin to CMUs are aerated autoclaved concrete (AAC) blocks. Sold under several brand names, AAC blocks are made with a mixture of portland cement, lime, silica sand, water, and aluminum powder. A reaction between the cement and aluminum creates tiny bubbles of hydrogen that increase the mixture’s volume fivefold.
FURTHER RESOURCES
BuildingScience.com:
Interior Insulation Retrofits of Load-Bearing Masonry Walls in Cold Climates
Concrete masonry unit walls are durable and easily erected
A tried-and-true system
Concrete masonry units (CMUs) are the standard hollow concrete blocks; the product has been around for more than a century. CMU use is more common in the southeastern U.S. than in cold-weather regions. CMUs are resistant to fire and insects, and, with adequate steel reinforcement, also offer high wind resistance. Walls can be insulated on the inside or the outside.
An only slightly younger cousin to CMUs are aerated autoclaved concrete (AAC) blocks. Sold under several brand names, AAC blocks are made with …
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6 Comments
Autoclaved Concrete
I would like to see more third party information and commentary regarding building with aerated autoclaved concrete (AAC). I designed a 2-story 2600sf house out of AAC almost ten years ago, and the owners are very happy with the decision to use it. I'm in a hot-humid climate. I'm assuming there's little on the subject primarily due to so few homes and businesses building with it.
Concrete block homes in Florida
Can we glue 3/4" styform to the inside walls to increase the R value of the wall?
Then finish with paneling or a laminatred panel to finish the wall. Now will the foil side of the styaform face the out side or inside?
Thank you for reading any your suggestions
Response to Doug
Doug,
Q. "Can we glue 3/4" styform to the inside walls to increase the R value of the wall?"
A. Yes.
Q. "Now will the foil side of the styrofoam face the outside or inside?"
A. The foil facing will not provide any thermal benefit unless it faces an air space. If you glue one side to the concrete block, don't glue the side with the foil. Face the foil side toward the inside; then install wood strapping, 16 inches on center, on top of the foam. You can attach your drywall to the strapping.
concrete block walls
new user and learning techniques. Would anyone tell me that by doing solid conc block exterior wall to a garden building without a render or sealant be?? ok as long as we have dpc under concrete slab? The internal wall is going to be plaster board on timber frame with a mulitfoil insulation layer between the timber and internal walls. Do I need to leave a gap? Thank you in advance!
Response to Simon Berry
Simon,
I don't know what "DPC" is, but I'm guessing it's polyethyhlene.
If you are building a garden shed, it hardly matters how you build it. There won't be any heat or air conditioning, right?
The main problem with an unplastered concrete-block wall is that it is ugly. If you don't mind looking at it, you'll be fine.
Of course, this depends on having a roof with adequate overhangs so that the walls don't get too wet. What's your climate?
Are there any environmental benefits for using concrete block foundations over cast-in-place concrete walls? Although each option uses Portland Cement, does one option typically use less?
Just curious of other reasons to use CMU over CIP concrete walls considering you can be losing some thermal mass properties and water/air leakage potentials. If there is less embodied energy in the production of CMU and is therefore greener for the planet, that could outweigh the negative. With proper installation, insulation, and WBR much of the air/water leakage could be eliminated. Any information you can give on this would be helpful.
Thank You!
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