How to Redo Drainage Tile

Cut out the top layer of grass, using a flat shovel. Place the grass to the side for replanting. Shovel out the top layer of soil and gravel. Dump the gravel along one side of the trench and the soil on the other side to keep them as separate as possible.

Examine the condition of the drainage tiles. Look for holes, dents and cracks. Remove the elbow and T-connectors, and look inside the pipes to see if they are clogged with debris. Lift the pipes out of the trench and replace any damaged sections.

Dig out the layer of gravel that lines the bottom of the trench.

Measure the depth of the trench with a tape measure. The trench should be approximately 18 inches deep and 8 to 12 inches wide.

Place a bubble or line level on the bottom of the trench. The minimum slope to ensure water flows towards the drainage outlet is 1 inch of decline for every 4 feet. Use wooden stakes to mark areas where the slope is too shallow.

Dig out the bottom of the trench with a shovel to make a consistent slope. Cut into the walls so they curve in a U-shape. Tamp the bottom and sides of the trench with a tamper to compact the subsoil and force out air pockets.

Return the bottom layer of gravel along the trench, and tamp until you have a 6-inch-deep base.

Lay the drainpipes on top with the perforations facing the sky. Cover the pipes with a drain sock to prevent small debris particles from entering the system and protect the pipes.

Shovel the top 6 inches of gravel over the tiles, and line the top with geotextile fabric. The fabric helps keep large chunks of debris from blocking the passage of water.

Mix an equal portion of sand with the soil and refill the trench to 1 inch from the surface. The sand will improve the soil and make it easier for water to seep through. Set the patches of grass back over the exposed soil and water generously.