Wall Construction Techniques

Retaining Concrete

• Retaining walls, usually built with precast stones or concrete blocks, hold back soil that would otherwise collapse. The typical homeowner may have the skills to build a low retaining wall of 3 feet high or less, but leave higher walls to the professionals. A retaining wall needs to be set in a firm foundation of gravel or crushed stone in a trench below the frost line. Place the blocks level on the foundation and check for plumb with a string line. Many manufacturers make blocks that interlock. For example, the blocks may have tongues that fit into the grooves of the blocks under them.

Brick

• Brick walls for structures such as houses need the skills of a mason, but if you want to experiment, try to build a low, freestanding brick wall. The bricks should rest on a concrete foundation or footer that lies beneath the soil surface. A brick wall over 2 feet high should have two vertical sections, or wythes, to give it added stability. Set the bricks in a layer of mortar with the indented side facing up. Staggering the rows as you work keeps all the mortar joints from lining up, which weakens the wall.

Timber

• Another material for building a retaining wall, rammed earth, adds a natural look to the landscape. Construct a rammed-earth wall by placing a mixture of clay, sand and gravel into a form. Add a stabilizer such as cement to the mix. After compacting the earth, remove the form and enable the sun to cure the wall. Finish your rammed-earth wall with a material such as plaster or leave it bare.

Dry Natural Stone

• Walls made from field stones, natural stones found in the environment, do not necessarily require mortar. You can build a dry stone wall that remains stable and safe so long as you don't build it higher than 3 feet. Dig a foundation trench 3 inches wider than your base course and 8 inches deep. Crushed rock works well for the foundation material. Placing each stone in between the stones on the course below and keeping the flattest side down creates the strongest bond.