Installing a Window Well French Drain

French drains are common drainage systems, used to prevent ground and rain water from damaging a structures foundation and or interior dwelling.  French drains are made up of corrugated PVC tile and or gravel.  The french drain allows rain water and or ground water to be diverted around a structure and into a central collection area.

From the last article I wrote on weeping tiles, I added a french drain to the project during the clean out of the old clay tiles.  The french drain was added to a window well that had filled up with rain water under extreme heavy downpours.  In 2008 during a summer thunderstorm rain water pooled around the back side of the house.  This caused the window well to take on water.  The water had no where to go and so it passed the sliding glass basement window and into the basement.  Due to the spot close to a floor drain the homeowner did not have much damage.  However, it was enough of an issue that they decided to fix the problem.

There are two good scenarios for adding a french drain to a window well.  The first benefit is that any large mount of water getting into the window well will be diverted down to the weeping tiles and then to the city sewer line and or to a sump pump.  The second benefit is having an extra place to be able to clean out the weeping tiles if needed, especially the clay weeping tiles.

This hole was hand dug due the closeness of a concrete pond and the house.  The depth was close to seven feet before hitting the top of the clay weeping tiles.  The sides of the pit were about five feet apart and four feet from the house to the pond.  It is very important that when digging you brace the walls if needed and have someone watching you just in case of a cave in.  We did not have to brace the walls as we had compacted sand that stayed moist all the way to the bottom.

The first picture shows the basement footer (straight line) at the bottom and a indent in the earth from a removed section of clay tile.  These clay tiles are easy to remove.  Once the tile was removed it was time to start cleaning the system.  To the left of the window was the end of the clay tile.  The builder must have just thrown pea gavel into the end to stop dirt from entering the system.  However, on the right, the tile runs horizontally all the way down the house.  The tile continues running under the inside basement floor and on each side by a "T" connector, connecting the outside tile to the inside.  I located the "sand trap" clean out in the basement and opened it up so that I could see how well the water runs from the outside tiles to the inside tiles and then continuing out to the sewer line.

The image on the left side shows the new clean-out/french drain pipe coming out of the old clay tile.  We connected the old section of clay tile with new corrugated PVC.  We used two adapters into the old clay tile and one "Y" adapter.  Then we sleeved the vertical pipe with cloth and stuck it into the "Y" adapter.  The landscaping cloth sits on the bottom then the connected PVC pipe on top.  Then pea gravel went down to hold everything in place.

Next we added more landscape fabric up the sides and then more pea gravel.  We back filled with dirt as we went along.  So the pea gravel will continue up the side of house and stop just under the window.

Just below the window is where we stopped with the pea gravel and landscape cloth.   We cut the top of the pipe off to

just above the pea gravel.  The picture does not show this but we added a drain cap to the top so that nothing large goes down the tile.  We also left the cloth over hang as so no small bugs make their way down the pipe as well.

This is the final shot of the project but it's not quite finished.  The homeowner is going to add some river rock to the bottom.  This will cover up the pea gravel and bricks.  Since we did not come up as far as I liked  we added some bricks to raise the window well and to level it out.   I tested out the project by putting in a garden hose into the well and letting it run for ten minutes.  It did not fill up and I could tell that water was getting to the weeping tiles by seeing it flow through the "sand trap" in the basement.

Side Note:  The PVC pipe in the photos were for the pond.