Pressure treated wood has been used for many years for telephone poles, docks, bridges and even as building foundations in the place of masonry. Decks will almost always be constructed using pressure treated wood for the framing materials. Treated wood meets a variety of essential requirements for this purpose. It is strong, straight, resistant to decay and insect infestation, highly durable, easy to work with, has widespread availability and is inexpensive. Pressure treated wood can also be used as a low cost alternative for decking and rail material but is usually considered too unstable as it can warp and split as it dries in the sun. Cedar and redwood are preferable for their aesthetics appeal. Health concerns over high exposure levels and its ugly greenish color usually limit its use for visible surfaces.



BUT, as a retaining wall? Often, we are called upon to repair or replace failing timber walls. The common denominator of these calls is the state of timber walls upon removal. We will replace any portion of an existing wall with the material requested; however, we prefer to install the most durable products that will perform for a lifetime, rather than a few years.

Timber walls will need to be replaced, and the bigger they are, the replacement cost seems to grow exponentially. Segmental retaining wall systems, like Allan Block, Pisa, and Keystone remain flexible, will not crack, will not decompose, and will not leech toxins into surrounding soils. The cost for block over timber is higher, but particularly for larger installations, will offer by far the best long term value.

You will spend more now for a segmental wall (usually about 30% to 50%), even more for a poured concrete wall (sometimes over 100%), and even more to repair or replace an initially cheaper brand new timber wall in 15 or 20 years (Often more than TRIPLE the original cost). We install all of the above, but we also believe you should see long term value for any larger installation.

Pressure Treated lumber retaining walls are reinforced with "T" shaped lumber tie-backs into the hill the wall must support. Once the placement of the tie-backs is determined, proper nailing and spiking must follow to ensure an adequate structure. This process allows the wall to support the hill above until the wood deteriorates. Creosote railway ties are toxic and have for the most part already spent many years punished and weakened from service on railways. Pressure treated wood is in fact not intended or designed for long term direct contact with soil.

Concrete Block (Allan Block, Pisa, Keystone) will not rot or decay and are made with more than three times the strength of a standard concrete cinder block. As a result, these walls are far more durable than pressure treated wood and have a projected product lifespan of about 75 years. Pressure Treated lumber in contact with soil and water will decay over time which will then fail to perform as an effective retaining wall system.

Concrete Block is somewhat more expensive than Pressure Treated lumber but will not require maintenance or replacement. Pressure Treated lumber is somewhat less expensive but will require more maintenance and ultimate replacement.

Actual Warning: Caution: Never burn treated lumber. This can release toxic fumes that are dangerous to breathe. Always use a dust mask when cutting treated lumber. Make sure to wash your hands before eating after handling treated lumber. Do not allow young children to come into contact with treated wood.