How to Backfill Dirt on a Hill Side for a Patio

Start the process on a cool, moist day and in the morning. Moist weather means moist soil, which eases the digging process. Don't attempt soil projects in rainy or extremely dry weather as mud and dry soil restrict construction attempts.

Mark out your intended patio area. Put stakes at the corners and run twine from stake to stake to build a border. Use a level to measure the twine; level twine will indicate the ultimate height of your retaining wall for the soil. Don't back fill the area without a retaining wall, as the soil will wash out from under the patio during any storm.

Dig a trench as the footer of your retaining wall. Dig the trench 1 foot deep and wide enough for the concrete blocks. Dig this trench along the bottom of the patio area and up into the slope. Discontinue the trench when the twine matches the natural soil level at the top of the slope. The top of the retaining wall should match this natural high soil level.

Mix quick-set concrete in a bucket, per the directions, and lay 1 inch of concrete along a 5-foot section of the trench on the lowest side of the slope. Put concrete blocks end-to-end in this concrete to set them, and measure them for level and use the rubber mallet to hammer down high points. Repeat this process along the bottom side of the retaining wall, and move up the sides to the end of the trench. At the top of the trench, adjust the depth of the trench as necessary so that the top of the concrete blocks matches the twine line in height and level. Allow the concrete to cure for at least 12 hours.

Build additional layers on the wall until the top of the wall matches the twine line on all sides of the plot. Spread 1 inch of concrete on the existing blocks and set new blocks down. Use the rubber mallet to adjust the blocks and the level to ensure an even set. Give concrete 12 hours to set between each layer of bricks.

Pour fill dirt into the low end of the site to even the soil level. Fill the dirt to the top of the retaining wall and rake it to match the high point of the site. Fill dirt doesn't settle, absorb water or drain like topsoil, compost or garden soil, and so offers the best, most secure foundation for structures like patios.

Run a compactor, available for rent at home improvement warehouse stores, over the site and focus on the new fill dirt. The compactor presses and settles any loose soil. Add more fill dirt as necessary and run the compactor again.

Allow the fill dirt to settle for three to four days, and repeat this process.