How to Build a Simple Reinforced Wood Retaining Wall

A retaining wall holds back soil, either in a planting bed or on a slope or hillside. It can be built out of anything - from stone to wood to poured concrete - and it can significantly alter the contours of your yard or garden. These guidelines cover a low, reinforced wood wall. For anything stronger, you'll need a contractor.


Step1
Figure out where and why you want a wall: at the bottom of a gentle slope to create a new planting bed? Between two beds to provide contour and definition? (If the answer to this is "to keep my house from sliding down the hill" see Warnings below.)


Step2
Use a trowel, shovel or grub axe to chop out the cut (a combination of ditch and ledge) where your wall will start.


Step3
Cut 4-by-4 posts to a length equal to the height of your wall plus the amount they will be sunk into the ground; your building code will tell you how far they need to be sunk.


Step4
Dig holes for 4-by-4 posts at the inside base of your wall every 4 feet.


Step5
Lower the 4-by-4 posts into the holes.


Step6
Pour concrete around the posts to ground level.


Step7
Level the concrete. Allow to dry and cure for a week.


Step8
Cut boards (or buy pre-cut boards) - 2-by-6s or 2-by-12s are a good choice - to fit the length of your wall. For example, if you're building an 8-foot wall, you'll have sunk three posts - two 8 feet apart and one in the middle (at the 4-foot mark) - so you'll want to use boards that are 8 feet long. If the wall requires more than one length of board to reach from end to end, you'll need to measure carefully so that they'll meet in the middle of a post where they can be bolted for stability.


Step9
Bolt boards to posts using carriage bolts, placing the boards on the outside of the post (use at least two bolts per board-post intersection).


Step10
Dig a couple of 2-inch diameter tunnels under the wall for drainage using a trowel or screwdriver.


Step11
Fill the drainage holes with gravel.


Step12
Backfill the cut - the area behind the wall - with at least 6 inches of gravel at the bottom for drainage. Fill the remaining space with soil to the top.


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