Interior French drain is a 4 inch pipe installed under the concrete slab, which will be connected to a water catchment system and will evacuate the overflow of water towards a ditch or a pipe. A drainage membrane is then placed on the interior foundation walls to direct the water coming through the foundation to the under slab drainage system. Once the installation is complete, concrete is poured over the system and the homeowner can redesign their basement.
An interior French drain system should not be confused with an interior gutter system. Some reputable companies install a patented system that is installed over the footings. This is a serious mistake that will cause heavy damage to the basement. Being on top of the footing, it only captures water when it is in contact and applies pressure on the concrete slab. The concrete floor remains wet at all times and mold can spread very quickly. If your intention is to opt for an interior French drain system, we recommend that you contact one of our experts to evaluate all the factors in place at your property. Our expertise is free as well as our good advice.
Steps to install an interior French drain
Installing a French drain inside a house or building requires several steps:
- Step 1: break up the concrete slab around the perimeter of the foundation
- Step 2: excavate to the bottom of the footing
- Step 3: installation of the French drain
- Step 4: installation of a catch basin with submersible pump or gravity discharge with check valve
- Step 5: cover the french drain with ¾” net certified stone in pyrite
- Step 6: install a Delta-MS type drainage membrane on the interior foundation walls
- Step 7: pour the concrete
Have an interior French drain installed
Installing an interior French drain is not very complicated in itself. However, the checks to be made to ensure that it is properly installed are crucial. Some people will install the French drain deeper than the building’s footings in order to gain height in the basement. This is a major mistake. The water will drain lower than the foundation and the building will be exposed to clay drying out.
Although the steps are less complicated than installing an exterior French drain, you should always call a professional from Lesage Excavation to ensure that the drainage system is installed properly.
Lesage Excavation has been providing French drain installation and repair services for over 15 years. Winner of the 2020 and 2021 Consumer’s Choice Award in the foundation repair category, our expertise and customer service are recognized throughout the Greater Montreal area.
We are available 7 days a week and 24 hours a day.
You have 3 ways to contact us:
- Call us at (514) 219-0125
- Send an email to: info@lesageexcavation.com
- Submit your project online here
We mainly serve the Montérégie, the Greater Montreal, the South Shore, a part of the North Shore as well as Ontario; and more specifically
Vaudreuil-Dorion – Montreal – Laval – Longueuil – Brossard – Candiac – Salaberry de Valleyfield – North Lancaster – South Glengarry – Alexandria – Hawkesbury – Rigaud – Hudson – Pincourt – Notre-Dame-De-L’ile-Perrot – Lachute – Montebello
We can also travel to more remote areas when it is a complex project and the owner cannot find a certified contractor in their area.