Mark Turnquest, CIPM
FRENCH DRAINS: WHY YOU NEED THEM
French Drains: Why You Need Them
Flat yard surfaces will need a deep French drain at some point. If you have a soggy yard or a wet basement, then a Freench Drain called a curtain drain is your cure. it extends horizontally across your property, directly uphill of the area you want to dry out. It intercepts water and channels it around the soggy spot.
Water runs into a gravel-filled trench, then into a perforated pipe at the bottom of the trench. areas with trees or shrubs, switch to solid pipe (not perforated) to reduce the risk of roots growing into the piping and clogging it.protect the drain from clogging with silt, drape landscape cloth across the base or footing and up the slope before adding the pipe and drain gravel. Near the top of the wall, fold the cloth over the top of the gravel, and top with several inches of soil.
The trench bottom should be sloped about 1 inch for every 8 feet in the direction you want water to flow. Depending on your situation.If there’s not enough slope for your drain system to work, you may need to pipe the collected water to a basin in the basement, where a sump pump can lift it and send it to the storm drain system
Water always flows downhill, and by the easiest route possible. That’s the basic concept behind a French drain, a slightly sloped trench filled with round gravel and a pipe that diverts water away from your house.
the drain name originated from Henry French, a judge and farmer in Concord, Massachusetts, who promoted the idea in an 1859 book about farm drainage.
If Water is Getting Into Your Basement
Install a deep French drain. Also called a footing drain, it runs around the perimeter of the house at the footing level and intercepts water before it can enter your basement.
If You’re Building a Retaining Wall on a Hillside
add a French drain behind the first course of stones or blocks.
Otherwise, water moving down the hill will build up behind the wall and undermine it. The pipe should rest on the same compacted gravel base or concrete footing that supports the wall.
It’s easy to install a french drain during new house construction, but much more difficult and expensive to add later. If you have tall basement walls, you may have to dig down quite a ways to access your foundation footing. Also, there are probably landscaping, decks, and walkways that will have to be ripped out in order to install the drain, adding to the cost.