Block Foundation Corners

Concrete blocks are designed to be laid in a running- bond (sometimes called a half-bond) pattern, with the vertical joints between blocks falling over the centers of the block below. If you have control over design decisions, lay out the distances between corners and bump-outs—as well as the width of door and window openings—in 8- or 16-inch increments to match the full- and half-length blocks.

1. Corner Crafting 

A running bond starts from the corner with each course offset by half a block from the one below it. By building up the corner first, a mason can establish the course heights and the plumb of the wall.

2. Accuracy Matters 

If blocks must be cut, maintain a running bond by staggering the cut blocks symmetrically. Joints as close as 4 inches from a joint in the course above and below will not affect the strength of the wall, but the appearance will suffer if the joints are off- center. Where portions of the wall will have the cores filled with concrete, keep the half- bond dead accurate.

3. Wings for Strength 

Wall intersections add strength to help resist soil pressure. Buttresses or “wing walls” can be built to stiffen main walls even if no partition is called for. Weave alternate courses in wing walls together as in a corner, and grout all cores and reinforce with steel.