This client in Kitchener reached out to us because they were having some drainage issues in their backyard. They had initially prepared a small French drain from the back of the yard to the middle, but it was not enough to combat their problems. They were getting a soggy yard after a rainfall and the water was not moving anywhere.

Whenever we confront an issue like this, we work to figure out the best solution of how we collect the water and where we are going to move it to. In this situation, we could not move it further into the backyard because the backyard had a slight slope towards the house. So our option was to move it from the backyard to the front of the house where we had enough slope to get that water into the swale between them and their neighbour’s house which would then slope further towards the street. We opted for a French drain to allow for a void space where that water would work its way towards since there was minimal surface water after a storm. If there was a major surface water problem we would have added a surface drain to capture that surface water as well.

This worked out to be approximately 150 linear feet of French drain. We also could not fit our mini excavator into this client’s backyard. The distance between the fence and the gas meter at the side of the house was not wide enough to allow for this. So we got creative and used our mini trencher tool to trench both sides of the French drain walls and shoveled the remainder into our electric wheelbarrow and into our bin for disposal.

We dig our French drain trenches a minimum of 12 inches wide and up to 16 inches deep or deeper if necessary. This depth depends on how much slope we have to work with on the property. If there is a good slope, we will have to start deeper in order to keep up with that slope otherwise our drain will eventually be too close to the surface. We need to have a 2% slope on our drainage pipe to adequately move water. If the yard is sloped more than 2%, that pipe gets closer and closer to the surface.

Once our trench is dug, we can then lay our non-woven geotextile fabric in the trench. This is a separation fabric that prevents dirt from working its way into the drain itself, but it still allows water to freely pass through it. The geotextile needs to wrap all the way around the trench covering the sides and top portion of the trench for us to put new soil and sod on top.

We then lay our pipe in the trench along the slope that we had prepared it for at 2% slope. If we need to we can add some of our 3/4″ angular crushed clean stone underneath. The pipe is a 4 inch corrugated perforated pipe that allows water into it as the trench fills up and carries it following the slope. We also take this opportunity to tie in any downspouts to the French drain using a PVC adapter and clean out so if any leaves come down the downspouts they get caught at the adapter with a cleanout installed to catch any shingle gravel to prevent further blockages.

With the pipe installed we can then start filling the trench in with 3/4″ angular crushed clean stone. Clean stone means that the aggregate is clean of fines or sand particles. This allows water to pass right through it. It is installed all around the pipe and on top of it seating the pipe in the middle of the trench with 4 inches of clean stone on either side and approximately 6 to 8 inches on top of it. We leave 2 inches of room for a layer of soil and sod to lay on top of the non-woven geotextile that is wrapped on top of the aggregate before adding the soil.

With this final step, the French drain is complete and provides a solution to our client’s backyard drainage problem.