So you’ve heard about spray foam insulation, but you live in a block home. This makes you wonder, is it even possible to have spray foam in a cement block home? What about in an older home?
The answer is YES!
The ideal way to install spray foam insulation in a cement block home is during construction. This allows professional installers direct access to the empty concrete block cells that will be filled with the spray foam product.
However, even after construction is finished, or during a remodel or retrofit of an older home, they can get foam insulation into a block wall by drilling a series of holes near the top of the wall and filling the wall one vertical cell at a time.
Working from the inside face (or the surface most likely to be covered with a finish), contractors drill 5/8-inch or 7/8-inch holes into the face of the blocks about 4 feet up from the floor to fit an injection tube running from a “mixer” that combines a non-toxic liquid resin, a foaming agent, and air.
Once the foam starts to seep through the injection holes (indicating a full cavity encompassing several blocks), the process is repeated along the length of the wall every 4 feet, and then again along the top of the wall about a foot short of its full height.
Here is how that works: as one cell fills up, the foam will start to exit from the hole in the adjoining cell, signaling the installer to move the hose to the next cell and seal the hole that was just filled. One vertical cell is filled at a time, until the entire block wall is full of foam insulation.
Another option would be to fur out an interior wall with wood or steel studs and spray the foam directly into place over the face of the block wall and in between the studs. Be advised, this option would imply added material costs in the form of studs, sheetrock, etc…and it would result in a slight – although measurable – loss of interior square footage.
These are only two examples of how spray foam insulation can be retro-fitted to existing concrete structures. Spray foam is a highly adaptable material, and it can be used on nearly any project.