A clogged or missing French drain usually shows up in the basement first: water at the base of the wall after heavy rain or during the spring melt, a damp smell that keeps returning, orange sludge in the sump pit. To know for certain whether the drain is blocked, crushed or was never installed, it has to be inspected with a camera or checked with a test hole. At Wilfrid David in Chénéville, we carry out these inspections for homes and cottages throughout La Petite-Nation.
What a French drain does
A French drain, also called weeping tile, is a perforated pipe laid around the foundation at footing level, bedded in crushed stone. It collects water from the soil before it can press against the concrete, then carries it away to a sump pit with a pump, a ditch or a dry well. As Quebec's home builders' association (APCHQ) explains in its homeowner sheet, the drain keeps groundwater from finding its way into the house.
Because it is buried, the drain is never in view. Its condition can only be judged from the signs that appear indoors, or through an inspection.
Signs that the drain is not working properly
The most common sign is water coming in at the joint between the foundation wall and the floor slab, often in the same spot, in spring or after a storm. If the water always appears in the same corner, make a note of it. That information helps pinpoint the section of drain involved.
Other signs are less obvious:
- a musty smell that persists even with the heat on;
- dark stains along the bottom of the walls;
- a sump pump that used to run every spring and now stays idle through the melt, which can mean water is no longer reaching the pit.
The Quebec government lists a foundation drain filled with sand or roots among the causes of excess moisture in a home. Over time, fine sediment clogs the stone around the pipe, then the pipe itself. According to the APCHQ, a foundation drain has a useful life of about 25 years, provided it is maintained.
Iron ochre
An orange, tan or dark brown gel-like material in the sump pit or at the drain outlet is usually not ordinary rust. It is most likely iron ochre, which the APCHQ describes as a material formed by iron-rich soil and water that develops in drains depending on the soil type and the water table.
Iron ochre does not mean the drain has to be replaced. It means the drain needs cleaning more often, so it does not clog and let water reach the basement. How often depends on the amount of buildup found during the inspection.
A house with no French drain
Some older houses, cottages placed on a foundation years after they were built, and certain additions have no French drain, or have one that was never properly connected. A few clues can give you a first indication:
- a sump pit in the basement with a pipe entering from the wall side;
- cleanouts, which are capped pipes rising out of the ground near the corners of the house;
- a pipe outlet in the ditch or lower on the lot;
- plans, invoices or information from a previous owner.
None of these clues confirms that a drain is in place, in good condition and properly connected. An on-site check is still needed.
How the drain's condition is confirmed
When the house has cleanouts, the inspection is straightforward. The APCHQ recommends them for exactly that reason: they allow the drain to be inspected by camera and cleaned without digging. Quebec's construction code does not require them, but some municipalities do. The camera shows what is inside the pipe (sand, roots, ochre, a crushed section or a separated joint) and how far along the line the problem is located.
Without cleanouts, the drain can sometimes be reached through the sump pit. Otherwise, a test hole at one corner of the foundation confirms whether a drain is there.
Depending on the findings, there are two possible solutions. A blocked drain can often be cleared with specialized equipment. If cleaning does not work, or if the pipe is crushed, the Quebec government recommends excavating the perimeter and replacing the drain. We describe that work in our article on damp basements.
Before concluding that the drain is at fault, it is worth walking around the house. Ground that slopes toward the foundation, downspouts that empty at the base of the wall or are blocked with leaves, and window wells filled with leaves and soil are also moisture causes identified by the Quebec government. Correcting them is sometimes enough, and it avoids replacing a drain unnecessarily.
When to call a professional
Contact us if water comes in at the same spot every spring, if you notice orange sludge in the sump pit, or if you are not sure if your home has a French drain. We can inspect the drain with a camera and review the footage with you before recommending any work. Call us at 819-428-3161 or see our French drains and camera inspection pages. If you are buying a property, our article on camera inspection before buying is also worth reading.
Filed under French drains · Camera inspection
