Yard and Foundation Drainage Tips

Yard and foundation drainage is based upon the relatively simple concept that water tends to flow downhill along the path of least resistance. It is virtually impossible to eliminate the natural flow of water, but relatively simple to redirect the flow.

Foundation drains, culverts, and ditches all create a downward sloping path of little resistance for water to flow to more desirable locations than your home or yard.

Assuming that a homeowner understands these basic concepts, there are still times that drainage ends up being insufficient or it works for a time and then fails. Homeowners are often at a loss as to what to do, resulting in costly repairs.

Here are a few tips to help ensure effective and long lasting drainage.

Yard drainage

Use a large enough culvert or pipe:

An insufficient diameter culvert is probably the most common flaw in yard and field drainage. Homeowners will often feel that the 8" pipe they ran under their driveway should be more than enough to handle rain run off.

In time they notice that the embankment around the driveway is deteriorating at a faster and faster rate. This is because, while the pipe is typically sufficient, heavy rains have taxed it to capacity.

While these rains aren't enough to flood the driveway, some of the water goes past the pipe and erodes the embankment before entering the pipe.

As the embankment erodes there is less and less resistance to the flow of water along this path which leads to further erosion. As a general rule the flow of water shouldn't fill the culvert more than half way during any reasonably predictable rainfall.

Obviously severe flood conditions may over tax the system, but a culvert that is more than half full on any sort of recurring basis is insufficient.

Grading the slope of your yard is by far the most effective strategy against standing water. If your yard has a consistent downward slope towards a desirable destination for water, it will be impossible for rainwater to collect. A drainage ditch is the second most effective strategy.

The exposed nature of a ditch makes it easy to maintain, and it will be able to collect excess water along its entire length without resistance, unlike the few fixed points and the resistance of granular fill associated with in-ground drainage.

Neither is always possible due to aesthetic reasons or existing grade, but these methods should be considered before adding in-ground drainage.

Incorporate retention ponds and catch basins:

Retention ponds and catch basins help reduce the erosion problems associated with heavy rainfall that overtaxes a drainage system.

They also provide a means to remove silt and other eroded materials that may build-up inside drainage pipes in the same way that clean-outs help you clean the waste lines in your home. Retention ponds can be an aesthetic addition to the yard as well.

By adding a retention pond to an area that frequently holds standing water, you can transform a mud pit into a center piece with a "if you can't beat'em join'em" attitude.

Foundation Drainage

Cover foundation drains with granular fill:

A light sprinkling of gravel under the foundation drain will help prevent mud from rising and clogging the drain, but it is the granular fill above the drain that provides a path for water to fall into the drain.

The granular fill should extend from the drain to near the surface; too much soil above the fill can prevent rainwater from penetrating the fill, and make your drainage less effective.

Cover the granular fill with straw before adding soil:

Loose soil will often work its way into the cracks between gravel and other granular fill. In time the soil clogs the fill and makes the drain ineffective.

Straw will prevent loose soil from entering the granular fill. By the time the straw rots, the soil should be hard enough to remain above the gravel.

Gutter downspouts:

Down spouts should be connected directly to your foundation drain or pointed towards an area that is graded significantly away from your home.

Down spouts that direct water near the foundation of your home can send water into a basement with even the most effective of foundation drains.

Seal the foundation:

It is nearly impossible to make a basement entirely water tight, but a tar sealant or concrete parging mix will provide greater resistance against water entering your basement.

This makes it more likely that water will enter the foundation drain. Small cracks in unsealed foundations will often provide a path of less resistance for water than the drain you have installed.

Sump pumps:

In most cases the slope of a foundation drain will be sufficient to direct water away from your home, but homes near sea level, flood plains, or rivers may occasionally find that the water table rises above the drainage they have installed.

A house should not be built in a location where this happens frequently, but if the water table occasionally rises above your basement floor you really have only one economically feasible option. Actively pump the water away.

Sump pumps can pump water far enough from your basement that the slope of your drain becomes sufficient to continue its flow.

Install cleanouts and vents along the drain route:

The same as waste lines, a foundation drain will flow more effectively if it is ventilated for air to escape. A few well placed, accessible clean-outs can turn a costly repair into a simple maintenance project in the event of future problems.

Related Topics: Linear French Drain Systems, installing down spouts drain lines, linear french drains