We at AIRLOCK Insulation do not endorse exterior wall retrofit if it is through brick. We just don’t believe that an adequate job is being done. It just looks like something is being done. The process we use is where a tube is inserted into the wall cavity. If there is a 4” brick and a 1” space between the brick and wall sheathing, then the wall sheathing needs to be penetrated, there is no way to insert a tube up the wall cavity to ensure the product reaches completely, or even reasonably.
This means that the wall insulation must be an interior retrofit to ensure that the walls receive a dense pack of cellulose at 3.5 pounds per square foot. 3.5 pounds per square foot is required to stop air infiltration.
So, what does this process look like? First, we move everything at least 4 feet away from the walls. Then we install drop cloths throughout the house to protect the floors. Then we install plastic walls to create 4-foot corridors. Once we have the area ready and the properties protected, we then drill 2 ½ inch holes into each wall cavity through the drywall. Next a tube is inserted into the wall and the cellulose is dense packed into each wall cavity.
After the wall is properly insulated, each hole is cleaned with a razor blade to ensure there are no burrs protruding out from the wall. We then insert a foam plug into the hole and recess it about 1/16 of an inch. Last, we use 2 coats of 5-minute mud to mud the hole. All that is required from the customer after that is to do a light sand and touch up paint. The plastic walls are removed, the drop clothes are collected, and the area is vacuumed and wiped down.
The results are immediately noticeable. The sound transfer from outside to inside is greatly diminished and the room immediately feels more comfortable.