How to Lay a Double Thick Brick Wall

Prepare a foundation. Mark the location for the wall with stakes and mason's twine and dig a trench along that line with a shovel or spade. Make the trench at least a foot deep and as wide as a third the height of the planned wall. Dig the sides straight to serve as concrete forms. Put two inches of compacted gravel in the bottom of the trench.

Fill the trench with concrete to just below ground level and level the top of the concrete using a flat mason's trowel and a level. Make this base as straight and level as possible. Let the concrete cure at least two days; a week is better, as concrete gains strength for at least a week.

Snap a chalk line in the center of the planned wall as a guideline for laying bricks to keep the wall straight. Stack your bricks near the work area and dampen them with a garden hose to keep them from absorbing too much moisture from the mortar.

Make a dry run by laying one line of bricks the length of the wall. Leave 1/2-inch between each brick. Mark the position of those bricks on the base with chalk. Set those bricks aside and mix mortar in a large container according to directions on the package; it should be a smooth plastic-like consistency, wet enough to spread smoothly but dry enough to set up firmly. Mix enough for about half an hour of work; if it starts to dry or get crumbly, discard it and mix a fresh batch.

Spread a mortar base with a pointed mason's trowel one inch thick and one brick wide about the length of three or four bricks. Furrow the center of the mortar line with the pointed tip of the trowel. Set those bricks in the mortar; press them in firmly. Spread 1/2-inch of mortar on the end of each brick starting with the second brick. Lay the first few and check the tops with a level to make sure they are level. Check the chalk guideline to make sure the line is straight.

Start another mortar line on the other side of your center chalk line. Lay those bricks just like on the first course. Continue working down the wall until both sides have one layer of bricks. Doublecheck the level, both lengthwise and across the bricks and make any adjustments before mortar starts to set. Tap any protruding bricks into place with the handle of the trowel.

Begin the second course or layer of bricks with a brick laid across the two end bricks. Spread a mortar base and set the second course of bricks just like the first, with 1/2-inch of mortar between each brick. Lay a crosswise or header brick across the two layers every fourth brick, to bind the two sides together. Add metal ties between horizontal joints every second or third brick to further bond the sides.

Lay the third layer or course just like the first; this will create a "running bond" pattern in which each brick overlaps two bricks below it. Lay the fourth course like the second. Continue down and up the wall until the desired height in reached. Finish the wall at the top with a layer of header bricks to make a solid cap. Finish joints between bricks with a steel finishing tool after every course. Press the convex end into the joints to force them into a concave shape which will shed water.