Interior and exterior French drain

The Cause

During heavy rainfall or quick snowmelt, water exerts hydrostatic pressure on the foundation. This leads to water infiltration or absorption into the concrete. This problem may be the result of:

• Poor drainage: In some cases, the drain appears unobstructed, but the surrounding soil may block the access holes and prevent water from draining out.
• Iron Ochre: The drainage system is clogged with orange sludge that sticks to the drain walls. This problem occurs when iron bacteria is present in the groundwater. When this bacteria comes into contact with the atmosphere, it oxidizes and produces a gelatinous material, which blocks the drain and prevents water from draining.
• No Drain: Often, in pre-1950 buildings, there is no French drain around the foundation footing. During heavy rainfall and quick snowmelt, the water pressure on the foundation leads to water infiltration and cement degradation.

The Long-Lasting Solution

• Excavation near the foundation using equipment that minimizes damage to the property.
• Cleaning and waterproofing of the foundation with a seamless polyurea lining, sprayed below ground level.
• Installation of a French drain at the footing of the foundation, covered with crushed stone.
• Connection of the drain to a catch basin to ensure proper water evacuation.
• Backfilling with suitable materials to guarantee soil stability.

Exterior drainage is a proven and durable method, but it can sometimes be limited by access constraints or require more extensive work. In townhouses, for example, shared walls often make excavation difficult. In such cases, the option of interior drainage can be considered.

The Scope of Work – Interior French Drain

The interior drainage system is a recognized and reliable waterproofing solution, equivalent to exterior drainage. This technology makes it possible to effectively waterproof your foundation while minimizing the demolition work required.

• Opening of a trench along the foundation walls.
• Installation of the interior drain at the footing of the foundation.
• Connection of the drain to a catch basin equipped with a sump pump to ensure proper water evacuation.
• Covering the drain with crushed stone, then finishing with concrete leveled to the existing slab.

Presence of Iron Ochre ?

If the drain on your property shows gelatinous, reddish deposits, it may be iron ochre. This buildup can clog the drainage system and lead to water infiltration problems.

Bisson Expert offers the installation of a rigid drain with cleaning chimneys, specially designed for properties affected by iron ochre. This system provides direct and easy access for regular maintenance, helping to keep your drains clear.

With this approach, you maintain a drainage system that is efficient, durable, and resistant to iron ochre without resorting to heavy or costly methods such as lifting the house.

Contact our experts today to find the best solution for your property.