How much does it typically cost to seal and caulk all the foundation cracks on a detached home?

Sealing and caulking all foundation cracks on a typical GTA detached home costs $500 to $3,000 for exterior surface sealing, or $1,500 to $6,000 if interior crack injection is needed for poured concrete foundation cracks that are leaking water. The total depends on the number of cracks, their severity, whether they are structural or non-structural, the foundation type (poured concrete versus block), and the access conditions.

For exterior surface caulking — sealing visible cracks in parging, the joint between the foundation and siding, around window frames, pipes, cables, dryer vents, and other penetrations — most GTA contractors charge $300 to $1,500 for a full-perimeter job on a standard detached home. The material of choice is polyurethane caulk, which offers excellent adhesion to masonry, remains flexible through GTA temperature extremes, and is paintable. A thorough contractor will also seal the cold joint where the foundation meets the basement floor slab if accessible from inside, as this is a common water entry point. Exterior caulking is one of the most cost-effective foundation maintenance tasks — a $500 to $800 caulking job can prevent thousands of dollars in water damage.

For crack injection on poured concrete foundations, the industry-standard approach is injecting either epoxy or polyurethane foam into the crack from the interior. Epoxy injection creates a structural bond and is used for dry, non-moving cracks — it is essentially welding the concrete back together. Polyurethane injection expands to fill the crack and remains flexible, making it ideal for cracks that may still experience slight seasonal movement and for actively leaking cracks. Crack injection runs $300 to $800 per crack in the GTA, and a typical detached home might have anywhere from two to eight cracks requiring treatment. Most GTA homes built on poured concrete foundations develop shrinkage cracks within the first few years — these are generally non-structural but will eventually allow water in as the exterior dampproofing ages.

Concrete block foundations cannot be crack-injected the same way. Block foundations develop cracks along mortar joints (step cracks) and sometimes through the blocks themselves. Exterior repair involves grinding out the cracked mortar joints and repointing with Type S mortar, then applying a waterproofing coating. Interior repair may involve parging the block wall with a waterproof coating. Block foundation crack repair typically runs $1,000 to $4,000 depending on the extent of deterioration.

Before any sealing work, a qualified contractor should assess whether the cracks are structural or non-structural. Hairline cracks (under 3mm), vertical cracks, and diagonal cracks near corners are typically shrinkage or settling cracks and are non-structural. Horizontal cracks, stair-step cracks wider than 5mm, or cracks with lateral displacement indicate structural movement — possibly from lateral soil pressure, frost heave, or foundation settling — and require professional engineering assessment before any sealing. The Ontario Building Code requires that foundation walls maintain structural integrity, and covering structural cracks with sealant hides a problem that may be worsening.

After crack sealing, applying a penetrating concrete sealer ($3 to $7 per square foot) to the entire foundation and parging surface provides an additional layer of protection against moisture absorption and salt damage. This is especially valuable for GTA homes where road salt and de-icing chemicals splash against foundation walls all winter.

All foundation contractors must carry WSIB coverage in Ontario. Get at least three quotes and ask each contractor to identify which cracks are structural versus cosmetic before committing to a scope of work.