Foundation services on the South Shore: Longueuil, Brossard, Boucherville

Sous-Sols Experts Inc. has served the South Shore (Rive-Sud) since 2013. RBQ-licensed contractor #5668-8765-01, SOPREMA-certified applicator.

Overview. The South Shore of Montreal combines two geological signatures: heavy clay from the Champlain Sea era (Longueuil, Boucherville, Saint-Lambert, Saint-Hubert) and sandy soil zones near the Richelieu (Saint-Bruno, eastern Sainte-Julie). The two profiles create different foundation problems: clay movement in the flat zones, erosion and settlement in the sandy zones. This page covers the services Sous-Sols Experts offers across the South Shore and the local particularities to know.

South Shore soil and foundations

Heavy clay covers most of Longueuil, Boucherville, Saint-Lambert, Saint-Hubert, Greenfield Park, and a good part of Brossard. It is the same sensitive clay as on the Island of Montreal, with the same consequences: seasonal swelling when wet, shrinking when dry, lateral pressure on foundation walls, vertical movement under footings. Homes built between 1960 and 1990 are most affected, and the French drains from that era (perforated tile or clay pipe) are at end-of-life. Further east and south, toward Saint-Bruno-de-Montarville, eastern Sainte-Julie, and Mont-Saint-Hilaire, the soil becomes sandier and the problem shifts: less clay movement, but water moves faster and drains clog with migrating sand.

Foundation crack repair on the South Shore

Foundation cracks on the South Shore follow the same categories as in Montreal: fine vertical (cosmetic), vertical that leaks (polyurethane injection), horizontal and stair-step (structural). South Shore particularity: the concentration of 1960s-1980s homes with concrete slab and block foundation walls (notably in Old Longueuil and Saint-Hubert) generates many stair-step cracks in block walls. The diagnosis and treatment are the same as Montreal, but structural engineer evaluation is more often required for older block walls. Typical price: $400 to $700 for injection, $2,500 to $8,000 for structural repair. Details on our crack injection page.

French drain on the South Shore

French drain work is often the primary service requested on the South Shore: aging drains (1960-1990) combined with high water table in certain sectors (notably central Longueuil and parts of Boucherville) creates high spring infiltration risk. We install new French drains in perforated PVC meeting current standards, with drainage protection membrane and clean crushed stone backfill. On the South Shore, access to the back wall is often better than in Montreal (wider lots, fewer attached buildings), which keeps prices on the lower end: $7,000 to $15,000 for a complete side, $15,000 to $22,000 for three sides. See our French drain page.

Waterproofing on the South Shore

Exterior waterproofing with SOPREMA membrane is the permanent solution for a South Shore foundation that takes water recurrently. South Shore context: municipalities often require a soil study for major projects (complete foundation rehabilitation), and the municipal permit can take 2 to 4 weeks in Longueuil and Brossard. We manage the permit request as part of the project, which adds $300 to $800 in administrative fees but accelerates the process. See our waterproofing page for the complete process.

Sump pump on the South Shore

For sewer-backup-risk zones identified by Longueuil, Brossard, Boucherville, and Saint-Lambert, the backwater valve is mandatory under municipal connection subsidy programs. We install Zoeller sump pumps with backwater valve compliant with municipal standards. Typical price: $1,500 to $3,500. Several South Shore municipalities partially subsidize the valve ($200 to $700), reducing the homeowner’s net price. We provide the documentation needed for the subsidy request.

South Shore coverage

Sous-Sols Experts serves the immediate South Shore of Montreal:

• Longueuil (Old Longueuil, Saint-Hubert, Greenfield Park, Le Moyne)
• Brossard
• Boucherville
• Saint-Lambert
• Sainte-Julie (all areas)
• Saint-Bruno-de-Montarville
• La Prairie
• Candiac
• Sainte-Catherine
• Saint-Constant
• Saint-Mathieu and Saint-Philippe
• Varennes and Verchères
• Beloeil and Mont-Saint-Hilaire
• McMasterville and Saint-Basile-le-Grand

On-site visit and diagnosis are free for these areas. For more remote zones (Saint-Hyacinthe, Granby), contact us: we evaluate case by case based on project nature and scale.

Why an RBQ contractor for the South Shore

On the South Shore as everywhere in Quebec, any foundation work requires an RBQ licence. Specifically on the South Shore, several municipalities actively verify contractor licence at permit request (Longueuil, Brossard, Boucherville). Working with an unlicensed operator means risking a municipal permit refusal in addition to limited recourse if the work fails. Sous-Sols Experts holds RBQ licence 5668-8765-01, valid for residential foundations. We always provide the documentation needed for permit requests.

Free South Shore inspection

If you live on the South Shore and you want a real diagnosis before a price, the on-site inspection is free. We typically arrive within 48 hours and deliver a written quote within 24 hours. No obligation, no sales pressure. Call Pietro at (514) 979-5425 or use the contact form.