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Cosmetic vs Serious Construction Defects: Which Ones Actually Matter
Builder problems Warranty From a builder
Cosmetic vs Serious Construction Defects: Which Ones Actually Matter
A nail pop and a cracked foundation both show up as a crack in drywall. One is a Saturday job with a putty knife. The other is an engineer. Here is how I sort what I see on a walk-through, and how Tarion sorts it.
Short version: Cosmetic defects affect how it looks; warranty defects affect how it works; structural defects affect whether it stands up and stays dry. Hairline drywall cracks, nail pops and paint are cosmetic. Doors that do not close, water where it should not be, and anything electrical or mechanical are warranty items to report in writing. Cracks that are wide, stepped, growing or wet, floors that slope, and walls that bow are serious: photograph, measure, and call an engineer.
The three buckets
| Bucket | What it looks like | What to do | Tarion coverage (contract homes) |
|---|---|---|---|
| Cosmetic | Nail pops, hairline drywall cracks at corners and above doors, paint touch-ups, grout shrinkage, minor trim gaps, small scratches | List it, fix it at the one-year mark in one visit; most builders do a year-end touch-up | First year, if it was there at the PDI or appears within the year and exceeds the construction performance guidelines |
| Functional (warranty) | Doors and windows that stick or leak air, a dripping fixture, a cold room, a damp spot, cracked tile, a deck board cupping, a furnace that short-cycles | Report in writing with photos; builder repairs under the one-year or two-year warranty | One year for workmanship and materials; two years for water penetration, electrical, plumbing, heating and exterior cladding |
| Serious (structural or water) | Cracks wider than 3 mm, stepped or diagonal, or growing; water entering the basement; floors out of level; walls out of plumb; roof or beam deflection; foundation movement | Photograph with a tape measure, mark and date the crack ends, stop any work that covers it, get an engineer’s opinion, notify the builder and Tarion in writing | Seven years for major structural defects; two years for water penetration |
Tarion publishes construction performance guidelines that say, item by item, what counts as a defect and what counts as normal. A drywall crack under a certain width is normal. A door that will not latch is a defect. Reading the guideline before you argue saves everyone a bad afternoon.
Cracks: the one everyone worries about
Concrete shrinks as it cures, wood dries and moves, and a new house settles for a year. Hairline vertical cracks in a poured foundation wall, less than about 3 mm and not leaking, are normal and are usually sealed from inside. Horizontal cracks, stepped cracks in block, diagonal cracks running from the corners of openings, and any crack you can slide a dime into and that is longer than it was last month are not normal. Neither is a crack with water or efflorescence on it.
In drywall, the normal ones are at the corners of doors and windows, above doors, and along the ceiling joint where truss uplift lifts the ceiling in winter. Truss uplift is the harmless cause of the scariest-looking crack in the house. A crack that runs diagonally across a wall, or opens and closes with the seasons more than a hair, deserves a second look.
For ICF walls, cracks are rarer because the foam faces hold the concrete and the rebar is continuous, but the same rules apply to the ones you can see at openings.
Water: never cosmetic
Any water where it should not be is a functional defect at least and a serious one if it is coming through the foundation, the roof, or a window. Stains, bubbling paint, a musty basement, frost on the inside of a window frame in January, ice damming at the eaves: all of these have a cause in the construction, and all of them get worse. Report them the day you see them, with a photo, and keep reporting until they are fixed. Why new basements leak explains the usual suspects.
Mechanical and electrical: functional until proven serious
A furnace that cycles every few minutes, rooms that will not hold temperature, a bathroom fan that runs into the attic, a breaker that trips: functional defects under the two-year warranty, and usually a design or installation problem rather than a dangerous one. Exceptions that are urgent: any smell of gas, a carbon monoxide alarm, warm outlets or breakers, aluminum wiring, and water near electrical. Those get the utility, the ESA or a licensed trade the same day.
How to document any of them
- Photograph with something for scale: a tape measure, a coin, your hand.
- For cracks, mark the ends with a pencil and the date. If it grows past the mark, you have evidence of movement.
- Write a dated list, one line per item, and send it to the builder by e-mail so there is a timestamp. On a Tarion home, file the 30-day and year-end forms on time; late forms lose coverage.
- Keep every reply. Documenting your project sets out a simple system.
- For anything in the serious bucket, get an independent engineer’s letter before the builder repairs it. A repair without a diagnosis is paint over a problem.
When to stop and call someone today
Floors that have become noticeably out of level. A door or window that suddenly will not open. A crack you can see daylight or water through. A beam or lintel that has sagged. A bowing foundation wall. Any smell of gas. None of these wait for the year-end form.
Related guides on this site
Sources and further reading
Questions people ask
Are cracks in a new house normal?
Hairline cracks in drywall at door and window corners and small vertical shrinkage cracks in concrete are normal in the first year. Cracks wider than about 3 mm, stepped or diagonal cracks, cracks that keep growing, and any crack that leaks are not; photograph them, mark the ends, and get an engineer's opinion.
What does Tarion consider a defect?
Tarion's construction performance guidelines define it item by item. Broadly: one year for defects in work and materials and Code violations, two years for water penetration, electrical, plumbing, heating and cladding defects, and seven years for major structural defects.
Is a leaking window a cosmetic issue?
No. Any water entry is a functional defect, covered under the two-year water penetration warranty on a Tarion home, and it gets worse if left. Report it in writing the day you see it.
Should I let the builder fix a serious crack right away?
Get an independent engineer to diagnose it first, in writing, then let the builder repair to the engineer's direction. A repair without a diagnosis hides the problem until the warranty has run out.
In the middle of a bad build?
Run your contract through the free checker to see what it actually gives you, and read the rest of the builder-problems series before you make the next move. We do not take sides; we have just seen a lot of these.
Reviewed and updated October 2026. Costs are Ontario ranges, not quotes; code references are to the Ontario Building Code in force at that date.
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