Timber Walls

Timber walls are often the choice of the DIY landscaper: they are the easiest to build and are usually the cheapest form of retaining wall.  But they do have disadvantages.  For many years timber walls were built using railway ties, although they are not so popular today.  They are not environmentally friendly, being impregnated with tar to prevent rotting, and the tar can also cause problems if it melts in the summer heat - sticking to clothes, hands and anything else that touches it.

Even using more modern alternatives, such as pressure treated timbers, a wooden retaining wall will only last about 15 to 20 years, and to get it to last that long will require occasional maintenance - pressure washing and painting with a fresh coat of sealer or preservative every few years.

The same rules apply to designing a timber pressure treated wall as any other retaining wall:  the ground forces have to be carefully calculated and allowance has to be made for water to drain away safely.  To provide stability for the wall it has to be built on a level foundation and staked with spikes and rebar.  It is also necessary to use a 'deadman' every few feet -- pieces of timber used as anchors attached to the main wall and extending horizontally from the back of it into the soil.

If the work is done properly timber walls have advantages in both costs and ease of construction.  Timber is also one of the best materials for fitting well into the landscape, as it is a natural complement to the plants and earth.