A thin, dry, vertical crack in an older Old Maple basement is usually a seal-and-monitor job. A horizontal, widening or leaking one needs its cause found first. Vaughan lists damp-proofing basements as generally not needing a permit.
Old Maple's original 1950s-era houses have had seventy years of freeze-thaw, wet springs and settling, and a custom rebuild going up next door can make you look at your own basement walls more closely. Most cracks you find are not an emergency. A few look just like the harmless ones until you know what to check. This guide covers how to sort them, what sealing costs, and what sealing does and doesn't fix.
Sort the crack before you seal it
- Thin, dry, vertical or diagonal: usually shrinkage or minor settling. Common home-inspection guidance treats hairline cracks as normal and cracks up to about 1/8 inch as worth watching, and sealing them if they leak.
- 1/8 to 1/4 inch: often still settling or shrinkage, but worth sealing because they can let in moisture and soil gas.
- Over about 1/4 inch, horizontal, stair-step or growing: treat these as a question for a foundation specialist or engineer, not a caulking gun. Horizontal and stair-step cracks are generally read as signs of pressure from soil or water against the wall. These widths are rules of thumb, not an engineering standard.
Mark each end of the crack with a pencil and a date, and photograph it beside a ruler. A wide crack that has not changed in years is less worrying than a hairline that appeared last month and keeps lengthening. If doors or windows have started sticking, or a wall bows inward, skip the monitoring and call someone.
Injection, surface sealing, and what each is for
Contractors commonly inject two materials from inside. Epoxy is rigid and is generally used on dry cracks to bond the concrete back together. Polyurethane is a flexible foam that expands to fill a crack and is the usual choice for one that leaks. Neither fixes a wall that is still being pushed in. If a quote is for injecting a horizontal crack, ask what the contractor thinks is causing it and how they know it has stopped. In an original-era house, also ask whether the wall is poured concrete or block: you can usually see mortar joints in block, and a crack that follows them is a different repair.
If water keeps coming back after sealing, the cause is usually outside: grading that slopes toward the house, a downspout dumping beside the wall, or a failed exterior membrane. Sealing from inside treats the symptom.
Typical cost ranges
These are general estimates from public Canadian price guides (HomeStars), not quotes. Ontario-specific figures are scarce, and access and finished walls change the number.
- Injection of a single crack: roughly $500 to $1,500, with epoxy and polyurethane priced similarly.
- Non-structural interior sealing: roughly $400 to $2,000 overall.
- Overall Canadian foundation crack repair: about $500 to $5,000, with structural problems at the top end and beyond.
Multi-crack jobs are often discounted, and you should get more than one written quote.
Does sealing help with radon?
Cracks are one of the ways soil gas enters a basement, so it is a fair question in a house this age. Health Canada's follow-up study of homeowners who tried to cut radon found those who only sealed entry routes averaged roughly a 13% reduction, compared with about 65% for active soil depressurization. Sealing helps a proper system work better, but it is not a fix on its own. Test first. Health Canada's guideline is 200 Bq/m³, and above it recommends a mitigation professional certified under the Canadian National Radon Proficiency Program.
Permits and approvals in Vaughan
Vaughan's list of work that generally does not need a building permit includes damp-proofing basements, and interior crack sealing sits well inside that spirit. The page is a general rule, though, not a guarantee, so check your actual scope with Vaughan Building Standards (905-832-8510). Underpinning, new openings and other structural changes are different and are dealt with as permit items. Two Old Maple checks: if your property is in the Village of Maple Heritage Conservation District, ask Vaughan's Cultural Heritage staff before any exterior excavation or masonry work, and if a neighbour is rebuilding, photograph your existing cracks first so you can show what was there before.
Quick answers
Can I seal a basement crack myself?
A thin, dry vertical hairline crack is a reasonable DIY seal with a hardware-store product. A wet, wide, horizontal or growing crack is not, because the cause needs finding first.
Does a basement crack in an older Maple home need a Vaughan permit to fix?
Vaughan's list of work that generally needs no building permit includes damp-proofing basements. Confirm your exact job with Building Standards first, since structural work such as underpinning is a different matter.
How much does it cost to seal a foundation crack in Ontario?
Canadian price guides put injection at roughly $500 to $1,500 per crack, and non-structural interior sealing at roughly $400 to $2,000. These are general estimates, not quotes.
Does sealing a foundation crack stop radon?
Not on its own. A Health Canada follow-up study found homes that only sealed entry routes averaged about a 13% radon reduction, so test first and use a certified professional if levels are high.
When should an engineer look at a foundation crack?
When it is horizontal, wider than about a quarter inch, still growing, or comes with a bowing wall or sticking doors. Sealing it without knowing why it moved can hide the problem.
Seal what is small, ask about what is not
A dated photo and a pencil mark cost nothing and make every later conversation, with a contractor, an engineer or an insurer, easier. If you want a hand with a straightforward seal, Rhodex can price it; anything that looks structural should be seen by an engineer first.
Related reading
- Small Repairs in an Old Maple 1950s Home: What to Check Before You Touch Anything
- How Do Building Permits Actually Work in York Region?
- How Do I Know If a Contractor Is Licensed in Ontario?
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