Replacing a Timber wall with Concrete Block

A common problem among existing retaining walls is that they are often built from timbers or railroad ties and have a shorter life then their concrete counterparts. As the wood begins to decompose the wall may begin to bow, crumble apart and wash out. The wall in this project was beginning to show signs of all of these with the additional problem of never being fully finished under the deck.

Wall project before

Previous home owners tried to dress up the area under the deck by enclosing it but this only invited humidity to speed up the rot process. We would also discover the posts of the deck either were not directly on footings or had rotted away.

This area of the yard was not a high priority for plantings and since access to backyard was also available on the other side of the house we elected to do the simplest wall – one wall L shaped with an 8′ height. In the future the deck could be remodeled to have a wood steps in front of the wall to once again provide access but was not necessary now.

Versa Lok Square Foot Block

The access to the backyard and final wall height for this project was a consideration for block type chosen. Our loader machine would have access to the backyard (face of the wall) only through the neighbors yard and the steep slope where the wall is provided additional challenges in getting product where we needed it.

Once all the under deck wood was removed we could start excavating our trench for the 8″ layer of compacted crushed gravel as our base. Next the base block layer was placed, leveled individually and centers filled with gravel.

Because of the height of the wall it was engineered to determine soil stabilization grid lengths and locations. We built up in layers compacting as we went to be sure settling would be absolutely minimal. Draintile was installed at the face ground level with outlets for excess water to drain. Drainage is also facilitated by the 12″ wide back fill of 3/4″ rock directly at the back of the wall. This block system incorporated pins as part of the installation process to tie the layers together and increases the strength of the wall.

Wall in Process

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