Cavity wall insulation can be useful for a variety of reasons. One of them is that you can reduce electricity utility cost. Wall insulation could prevent cold air from entering the interior of your house, especially during very cold night during winter. Thermal insulation material performs much better than regular bricks wall. Wall could block cold air, but it will become very cold as a result, causing your to burn more energy to warm up the interior. The foam material should also waterproof, or at least can block moisture. During a humid day, moisture could seep through various holes.

When the insulation material is exposed to rainwater or very humid air, it shouldn’t absorb any moisture. The insulation material should be highly durable and intrinsically water resistant. Fibers of the insulation materials should be well arranged to prevent air and moisture from penetrating the cavity. In fact, the insulating material itself doesn’t absorb water, just like plastics. So, even when a drop of water hit the insulation material, it will be deflected away. Cracks and holes need to be filled immediately. While the outer layer of the wall can be relatively water resistant, the cavity area can be vulnerable to moisture.

When moisture or even rainwater accumulates inside the cavity, it could permeate inside the wall. The material inside the wall can be subjected to constant moisture. Things can be so bad that directly under the cracks, there’s a puddle of water. This can cause the material inside the wall to rot. When it happens, the material itself will degrade and be decomposed. Some materials like wood could disintegrate into simpler organic materials. Combined with the humid environment, it will be a great place for mold and fungi to grow. This will add another problem in your home.

Mold can be quite dangerous for your health. Mold spores are not only allergic, but spores of some species could actually be quite toxic. This will cause many kinds of unwanted symptoms. On top of the allergic symptoms, family members can suffer from more severe conditions, such as chronic weakness or severe fever, due to exposure to toxic substance from the spores. Mold and fungi will feed on organic material inside the wall cavity, degrading the structure of your house slowly.

The problem can be quite serious is the crack is directly above the foundation block and it’s something that can be hardly noticeable. Rainwater penetration can happen for years causing concrete to slowly crumble due to mold growth and metal frame to rust.  Moisture problems caused by cracks can be effectively solved if you choose the right foam insulation material and technique. Before injecting the insulation foam material into the cracks or cavity, make sure that you clean up everything. In some cases, if the damage to the wall is serious enough, you may need to replace a few bricks or two, because the foam may not be sufficient to fill a big crack on the wall. This will ensure that the wall will be properly sealed.