How to Form Concrete Foundation Walls

Place the first block of polystyrene directly atop the poured footing. Normally, the block systems use a polystyrene glue that is stronger than mortar of the first row. On occasion, this glue is also used to give additional strength to the joints in the blocks as well.

Fit the blocks together akin to Lincoln Logs or Lego pieces. These blocks are designed to make assembly easier. Building corners are simpler than standard concrete walls, as corner pieces come premade or precast with the kit.

Consolidate your cement before pouring. There are several ways to do this. The most common way is to pour the concrete into a large table or bin and vibrate the mixture for about 20 minutes. The vibration pushes all air from the compound. This provides a stronger, more dense concrete free of troublesome air or water pockets that expand and crack when heated in the Summer.

Add a perlite mixture to the concrete if you want added insulation. Perlite is a volcanic rock pulverized into a powder. It is one of the most powerful insulating materials in the world, as it conducts almost no measurable heat. If you live in a very cold area, or an area with great swings in temperature, the perlite addition is important. These blocks themselves are made from insulating material, so adding perlite to the concrete mix will increase their insulating properties. Builders in areas with moderate climates can forgo this step.

Add rebar reinforcement. With the block system, rebar systems are expected, so blocks include locks for the rebar. Accordingly, placing the rebar is almost effortless. Normally, the number 4 grade rebar is used, which is about 5/8 inch. Most codes insist the bar penetrate at least 14 inches into the wall above, but that is a bare minimum.

Pour the concrete directly into the top of the block. The concrete used should be a minimum of 3500 pounds per square inch--psi--grade, though most builders will use 4000 psi for safety. The new insulating blocks now can carry a full 3 or 4 yards of concrete. Since the largest legal basement wall is 8 feet, this is not a problem. The concrete can be poured directly into the blocks and, given their design, the result would be an entire row of vertical blocks filled with concrete. The blocks themselves are made from insulating material, thereby increasing the insulation of your construction.