The initial step in retaining wall construction should be to determine the size or area of the retaining wall by linear foot. This will figure into the estimate of materials needed later. Mark off the area with a string line and allow for extra room on the sides of the retaining wall blocks for a good gravel base.

Estimate the materials required, chose ideal retaining wall blocks, the size you choose will determine the number needed, for example: if 12 inch blocks are used the number times the linear foot needed is obvious. If 8 or 16 inch blocks are used, convert total linear distance needed to inches and divide by 8 for an eight inch block. Estimate base material- gravel(3/4 quarry process) for under retaining wall, use 4- 6 inch gravel base, more if retaining wall is higher in size.

Preparing for a good retaining wall construction the base is the most important and will be the most time consuming process. Excavate by shovel or loader if available, use local digging laws to ensure that you avoid any buried cable. If possible use a landscape fabric under gravel for improved support and safeguard base from soil. Some areas may need a deeper base(6 or more inches) due to poor soil or recent disturbed soil from new construction. Next- get the gravel base in by wheelbarrow, shovel, loader, and rake it out to approximate level.

Grade the retaining wall base with a rake and 2X4 to get an even base where the wall will be placed. The string line ought to be in place with a proper level set and the direction of the wall. So when the base is ready and compacted to the correct string level, all you need to do is line the rear flat side of the retaining wall blocks with the string and keep on placing blocks. When installing string line, remember that the first coarse of blocks should be 3/4 buried for good support of the entire wall.
Use a plate compactor or like compaction device to get a good strong base for the wall. If the gravel is too dry, wet it down some with a garden hose to make it pack better. Grade additional times after each compaction until complete.

Lay the retaining wall blocks along the string line until the first layer is complete, be sure you have this first coarse secured well, some bury the first layer almost entirely or 3/4 buried so the base is strong. When layer 1 is done, the next coarse is easier, up to the height you want to make it. Use a landscape block adhesive between each coarse for further strength.

Some retaining wall blocks may must be cut to finish or match nicely to a foundation or other structure. Use a diamond blade chop saw to get a nice cut. measure block in place and cut on your marked line. Retaining wall caps are a great option to use, they add a better appearance and won’t allow weeds to grow between the joints on top of a wall. (depends on type of block used) secure with a landscape block adhesive for added strength.

Finish the retaining wall construction by adding or back fill any more base material or black dirt in front or behind the wall, seed grass if needed. If retaining wall is situated in an area that water drainage may be a concern, use a drain tile pipe along the back base of the wall and use rock or water friendly material for drainage purposes. Use this on the back of the retaining wall before black dirt or other soil is added.

Tip: Use Landscape Block Adhesive between each coarse of blocks, run a bead of caulk along the blocks, this will make the wall stronger and moisture won’t leak through the blocks, they will be sealed.

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