How Do You Lay Perforated Drain Tiles?

Drain tiles help support a home's foundation.

Foundation drainage systems are commonly referred to as "drain tiles." A crucial component of residential construction, they are responsible for keeping the soil dry to better support the weight of the home's foundation, and to enhance water dispersion from around basement walls. Seldom seen by homeowners because the systems are buried beneath the ground, their failure can cause damage to the home. Fortunately, most perforated drain tile is easy to lay and can be installed by an average homeowner over a weekend to enlarge or repair an existing foundation drainage system.

Things You'll Need

• Drain tile (4-inch perforated pipe)
• Filtration paper
• Bags of large gravel
• Shovel
• Carpenter's level
• Tape measure
• Wooden stake

Instructions

1. Measure out your intended trench dimensions in your yard, using a tape measure, so you'll have enough materials. Mark your dimensions with a wooden stake. Calculate enough materials to extend (or repair) the system per your estimated dimensions.

2. Dig a trench 12 inches wide and approximately as deep as the foundation footers in your home, using your shovel. Begin the trench next to the lowest corner of the home, and angle it downhill away from the home. The drain tile may either be connected to a sewer/drainage system, or allowed to end at a downhill location a certain distance from your home depending on your local ordinances. Terminate the trench according to your ordinances.

3. Measure the trench's slope to make sure it goes downhill its entire length. Use a carpenter's level to verify this slope at least every 3 feet of trench length. A good rule of thumb is to slope the trench 1/2 inch for every 1 foot of trench length. So a 40-trench would end approximately 20 inches lower than where it began. Dig out any high spots in the trench until it is sloped properly.

4. Fill the trench with 2 inches of gravel for its entire length. Cover the gravel with filtration paper. Lay the drain tile on top of the filtration paper. If using a single long piece of drain tile, make sure it lays completely flat and does not retain any coiling from the time it spent in storage. If using individual pieces, make sure they are connected together properly, so that they will not separate over time.

5. Connect the drain tile to a sewer or drainage system as required by ordinance. If no connection is required, just leave the end open. Cover the entire length of drainage tile with gravel. Backfill the trench with the soil removed while digging the trench. Pack down lightly. Keep any unused soil so that if any low spots form later (after settling), you will have material with which to fill it in.

Tips & Warnings

• Ask about the local ordinances and regulations regarding minimum standards required for drainage tile systems in your locality. Some regulations may call for closed systems (the drain tiles connect to the sewer system); others may stipulate free-standing systems (the drain tiles drain down a slope from the home). Most ordinances stipulate required lengths for drainage tile systems.

• It is a good idea to purchase a bit of extra material in case anything is wasted during construction. A simple rule of thumb is to get a bag of gravel for every 2 running feet of drain tile needed. Filtration paper may be purchased in the same quantity as drain tile.

• Always check with your local utility companies before you dig to avoid cutting utility lines.

References

• Ask The Builder: Foundation Drain Tile Installation