We’ve calculated how much we need, and mixed the mortar. Now, let’s lay it. Two tips to start: Mortar dries quickly, so mix it in small batches. Note that a block has a top and a bottom. The top has more surface for the mortar.
Lay out a dry run on the footing, spacing each block with 3/8″ spacers. When you’re comfortable the wall is laid out properly, mark the location of both end blocks in the first course. Take the blocks off the footing.
Now install a block at both ends of the course. Spread a substantial layer of mortar on the footing and place a corner block on it. Push down the block, so you can see about 3/8″ of mortar between it and the footing. Lay the other block the same way.
Stretch a line between them to guide you on the rest of the first course. To lay the rest of the blocks, spread mortar on the footing, and butter the end of the block that will join the block that’s in place. You can save a little time by setting a few blocks on end and buttering the ends ahead of time. Gently set the block down, letting the buttered end down last.
Tap it level with the handle of your trowel, and scrape off excess mortar with the blade. As you go, keep checking for level and plumb. And don’t forget to butter both ends of the last block.
Alternate the blocks on the next course. You’ll see the holes will line up. Depending on the code requirements for the job at hand, you should fill these with concrete. By filling a cell every 4′ to 6′, you can install anchor bolts. Once set, these hold on the mudsill, which is a board or series of boards capping the wall.