This is because it contains trapped air which cannot transfer energy by moving.
Are Brick Walls Good Insulators. Brick is a lousy insulator, your brick wall, if it's two course thick probably still has an r value of less than 2. You can find many old bldgs in diff parts of our country with a single layer stacking on the roof to reduce heat during summer.
Various Types Of Walls from dailycivil.com
Soil, and especially clay, provides good thermal mass; Concrete is not flammable and has good fire resistance, but there is a serious loss of strength at high. The most common method for attaching something to a brick wall is to drill into the brick itself and insert a hanger.
Aluminium, principally in the form of various alloys, is highly valued for its durability and especially for its light weight, while brass is frequently used for decorative purposes in facing.
Fired bricks can be solid or have hollow cavities to aid in drying and make fired brick walls are usually substantially thinner than cob/adobe while keeping the same vertical strength. Most of the brick surface isn't covered in mortar. The gap between two brick walls is filled with material that has a lower thermal conductivity than air. The best insulator is air.
