Design of Concrete Masonry Block Walls

Footings

• Concrete masonry block walls should never sit on top of the ground. Instead, footings must be dug in the location where the walls will be placed to create a sturdy base. Generally, the footings of a building should be at least 8 inches deep and up to 2 feet wide to ensure the durability of a concrete masonry block wall. The footings for concrete masonry walls contain a mixture of concrete blocks, builder’s sand and mortar.

Laying Blocks

• Once the footings for a concrete wall have been crafted, the wall can be built up from this underground base. The main above-ground section of a concrete wall consists of rows of concrete blocks stacked on top of each other. To ensure long-term stability of a wall, the seams between blocks should be staggered row by row and rebar should be used in the holes in the blocks for extra stability.

Adhesive

• Concrete masonry block walls require masonry adhesive, such as mortar, to secure the blocks together. Mortar applies to the top of each row of blocks in an even layer with a trowel and the blocks in the next row should be pressed down into the mortar. Mortar also seals the blocks together on the sides, securing the blocks and providing some leeway for movement of the blocks. Some manufacturers also make concrete blocks that interlock and don't require any adhesive.

Additional Insulation

• For use in homes and other buildings, concrete masonry block walls must have more than just the block layer. Building walls require the concrete wall structure, plus layers of installation and an interior wall surface. To create this design, wood wall studs must be spaced inside the concrete walls and covered with drywall, wood or cement backer board. Before installing the inside wall covering, like drywall or backer board, though, rigid, foam or loose-fill installation must be placed in the cavities between the studs.