This client in Waterloo reached out to us because they had some drainage issues in their backyard in between their shed, house, and above ground pool. This area was pooling water despite not being a low spot in their yard and not draining away after rainfall. The surface water would be gone shortly after the rainfall but they would be left with a soggy yard in this area afterwards. This is where we come in and offer our French drain services to be able to capture that water and move it to the best area possible on their property.

We first begin by asking our clients that reach out to us for our drainage services whether they have standing water or a soggy yard. If they have standing water long after a rainfall then we need to address this with a surface drain along with our drainage system to be able to capture that water. If it is just a soggy yard, we can opt for a French drain to create a void space for that water to go to and move it to where we want. Water will follow the path of least resistance so this is where creating a void space helps to address a soggy yard.

With the yard being relatively flat with a slight slope towards the deck and not towards the back of their yard, we opted to move that water towards the front of the house as there was a much better slope towards that area and into the swale between them and their neighbour’s property which would then carry a slope towards the street. This worked out to be about 150 linear feet of French drain. We were able to get a mini excavator barely between the gate and into this backyard. However, at a certain point we needed to just loosen the ground with the excavator while we backed out of the backyard and then come back with wheelbarrows and hand shovel it into them and into the disposal bin. Still we were able to use the machine for 70% of the work. We dug two parallel trenches between the shed and deck to ensure we captured all of the areas where there was water issues and then tied them into one long stretch from the backyard to just beyond their backyard gate.

We excavate our French drain trenches to a minimum width of 12 inches and a depth of up to 16 inches, or deeper if necessary. The required depth is determined by the natural slope of the property. If the slope is significant, we start the trench deeper to maintain a consistent grade, preventing the pipe from becoming too shallow as it progresses. To ensure proper water flow, we aim for a 2% slope along the drainage pipe. If the yard’s slope exceeds 2%, the pipe will gradually rise closer to the surface, which we work to avoid.

Once the trench is dug, we line it with a non-woven geotextile fabric. This fabric acts as a barrier, preventing soil from infiltrating the drain while still allowing water to pass through. It is crucial that the fabric fully wraps around the trench, covering the sides and top, so that when new soil and sod are placed on top, the drain remains protected.

Next, we install a 4-inch corrugated perforated pipe along the slope of the trench. If necessary, we add a base layer of 3/4″ angular crushed clean stone to maintain the pipe’s gradient. The perforations in the pipe allow water to enter as the trench fills, efficiently directing it downhill. At this stage, we also connect any downspouts to the French drain using a PVC adapter with a cleanout. This prevents leaves and shingle gravel from blocking the pipe, ensuring optimal performance.

With the pipe in place, we proceed to fill the trench with 3/4″ angular crushed clean stone. Using clean stone — free of fines and sand particles — promotes optimal water flow through the aggregate. We ensure the pipe is centered in the trench with approximately 4 inches of stone on each side and 6 to 8 inches above it. We leave about 2 inches of space at the top to accommodate a layer of soil and sod. Before adding the soil, we fold the geotextile fabric over the top of the stone to further protect the drain.

This final step completes the French drain installation, providing our client with an effective and long-lasting solution to their backyard drainage issues.