Cinder Block House Insulation-How To Fix It?

Cinder Block House Insulation

Cinder block houses often lack proper insulation, leading to temperature issues and energy inefficiency. To fix it, consider these steps:

  1. Install insulation panels or foam boards on interior walls.
  2. Fill any gaps or cracks with expanding foam.
  3. Apply a vapor barrier to prevent moisture.
  4. Finish with drywall or other suitable materials for improved insulation and aesthetics.

Cinder Block House Insulation Options

There are various ways of fixing insulation issues in cinder blockhouses. Here are the best options:

Spray Foam Insulation Method 

For cinder blocks or concrete wall houses, some layers are put up to have a completed wall. After the blocks have been laid, the wall is not complete until when drywall is installed. 

For this technique, spray the spray foam before installing the drywall. The cinder blocks may have studs, which you will have to chisel out to about a quarter-inch or even half an inch. These all depend on your contractor and architectures plan.

This is done so that when the foam is sprayed on the wall, it can get in behind the studs and prevent thermal bridging. Thermal bridging is a situation where there is uneven heat transfer. If you do not chisel out, different parts of the walls will end up having different temperatures. Usually, this leads to an overall reduction of thermal insulation.

Injection Of Insulation Foam

This method is not very different from spraying insulation foam on concrete walls, as explained earlier. It only differs in that the walls have already been built, and drywall has been installed. Generally, all wall-building processes are finished.

Here, you have to drill some holes into the existing wall and directly into cavities in the wall. Then insert the foam into the wall cavities and crevices. These cavities and cracks in the wall usually let air pass through them into and out of the house. The injected foam covers them and eliminates the issue.

This method is beneficial if you purchase an already-built house and later realize there isn’t insulation on the walls. It cuts the cost of having to rebuild the walls or take up other drastic measures.

Application Of Foam Boards

These foam boards do not have the same effect as the spray foam or the injection foam. In this method, you install the foam boards to the wall before the exterior finishing is done. You then attach the foam boards to the cider wall using a unique adhesive. Applying adhesives to the foam board makes it easier to stick firmly and securely to the wall. 

Caulk is used on the seams to make sure that there aren’t any air leaks. If you do not seal the seams between the foam boards well, air will still move around, and the whole process will have been redundant.

Unsealed seams cause condensation in the walls, as there will be two different temperatures meeting in there. The condensation can also lead to other complications such as mold and mildew growth.

Installation Of Polystyrene Beads

This method is mainly used when the top of the wall is not covered. You start by pouring the polystyrene beads into the open top of the wall and the crevices of the cinder blocks. Mostly these beads are poured into the wall after it has been built, then they are sealed in there. Sometimes you might uncover the top of your walls and find them already in there.

This method, however, has a major drawback. Since you pour the beads into the wall, if you ever cut into the wall for one reason or another, the beads would all pour out. The polystyrene beads are circular, and hence they would all follow each other out through the opening.

Therefore, once the beads are in, cutting into the wall is not recommended unless it is the last alternative to solving any wall-related issues that may arise.

Loose-fill Masonry Insulation Or Mineral Loose-fill Insulation

This method is the equivalent of adding sand-like material into the crevices and spaces in the walls or the cinder blocks. And, for it to work well, the top of the cinder block wall should be open. Just pour the loose-fill masonry to the open top of the cinder block wall ensuring all crevices and nooks are filled. 

This insulation method, just like the polystyrene beads insulation method, has a drawback as you cannot cut into the wall after its application. The same way sand moves from one end of an hourglass to the other; the loose fill would leave your wall after a hole is made into it.

It is hard to know if every crevice and nook has been filled with loose minerals since it is a long distance from the top of a wall to the ground. As the mineral goes down, there can be an obstruction that leads to some spaces being left open without filling.


Fixing an already insulated cinder wall involves redoing any of the above, making sure that the insulation is done to perfection. There are no other shortcuts to go over this issue. Most cinder block houses need insulation done by professionals to avoid future complications. The insulation method you choose is all dependent on your house and what your contractor can do for you.

How do you attach foam insulation to cinder blocks?

Attaching foam insulation to cinder blocks requires the right materials and techniques to ensure a secure and effective installation. Here’s a general guide on how to do it:

Materials Needed:

  1. Foam insulation panels or foam board
  2. Construction adhesive compatible with foam insulation
  3. Masonry screws or concrete fasteners
  4. Caulk (optional)


  1. Prepare the Surface: Ensure the cinder block walls are clean, dry, and free from any debris or loose material. If there are significant irregularities or protrusions on the surface, consider using a masonry grinder to create a flat and smooth area for the insulation.
  2. Cut the Insulation Panels: Measure the height and width of the cinder block wall sections you plan to insulate. Using a utility knife or saw, cut the foam insulation panels to fit those dimensions.
  3. Apply Construction Adhesive: Apply a continuous bead of construction adhesive onto the back of the foam insulation panels. Use an adhesive compatible with foam insulation to prevent damage to the foam.
  4. Press the Panels onto the Wall: Press the foam insulation panels firmly against the cinder block wall, making sure they adhere uniformly. Apply pressure for a few moments to ensure a strong bond.
  5. Secure with Masonry Screws: For additional support and to prevent the insulation from shifting, you can attach masonry screws or concrete fasteners at regular intervals along the edges and corners of the foam panels. Use screws specifically designed for masonry applications.
  6. Caulk Seams (optional): If using multiple foam panels, you can apply a bead of caulk along the seams between the panels to create an airtight seal and improve insulation effectiveness.
  7. Add Finishing Layers (optional): Depending on the intended use of the insulated wall, you may add additional layers such as drywall or other finishing materials over the foam insulation for a clean and polished appearance.

Can you put insulation in a cinder block?

Insulating cinder block walls is indeed possible and can greatly enhance the energy efficiency of a building. Cinder blocks, commonly used in construction, are made of concrete and have open cells that can be filled with insulation materials. However, it is important to note that the process of insulating cinder block walls involves careful planning and the selection of appropriate insulation types. By insulating cinder block walls, property owners can significantly improve thermal insulation, reduce energy consumption, and create a more comfortable indoor environment.

Final Word

Cinder block walls are elegant and cool to the touch in the summer. But as soon as winter comes, they become cold and create an inhabitable environment. Depending on the initial house architectural plans, the house may have an opening at the top cinder blocks or an exposed exterior wall. These plans are the ones that dictate how the insulation of the house can be done.

However, it is advisable to have this insulation problem handled during construction. This eliminates the hustle of destroying parts of the entire wall and redoing them when the seasons change and it gets cold.


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