Guide
How to Monitor Foundation Cracks
How can I tell if my foundation crack is getting worse without paying for a survey?
With a pencil, a ruler, a camera and a date. The whole point of monitoring is change, so you need a fixed reference and a recorded number, not a memory. Mark the crack's ends, measure and photograph it with a dated scale, and re-check in three to six months and again after the spring melt. Stable and dry with no change is excellent news; growth against a recorded baseline is the reason to move to a professional assessment.
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Published by Calgary Foundation Pros. Last updated August 16, 2026. This is general guidance for Calgary homeowners, not an engineering assessment of any specific property, and it is not a substitute for a professional engineer where one is warranted.
Most foundation findings only need to be watched, and watching well is a cheap skill that saves expensive mistakes in both directions: it prevents ignoring a real problem, and it prevents repairing one that was never moving.
This is the how-to for that watching.
Set a baseline: the point of monitoring
A single look tells you a crack exists. Only a dated baseline tells you whether it is changing. Before anything else, establish a reference you can compare against later.
- Photograph the crack with a ruler or coin in frame, and save it with today's date
- Mark the two ends of the crack in pencil with the date on both sides of the gap
- Measure the widest point and record the width in millimetres
- Run a finger across to check the faces are flush, and note if they are not
The tools that are good enough
Professional monitoring uses precise instruments, but for most cases simple tools answer the real question of whether a crack is moving.
- A glass or plastic crack gauge, or a simple piece of clear tape over the crack with a line across it: if the line parts, it has moved
- A steel ruler or callipers for width
- A straightedge and a level to check a wall for bowing
- A dated smartphone photo is better than nothing and easier to retrieve
How often to re-check
Routine monitoring is not daily. The intervals that matter line up with the seasons that move Calgary soil.
- Re-check in three to six months after the baseline
- Re-check again after the spring melt, the season of greatest change
- Compare to the recorded baseline rather than to memory
- Do a full pass on all the cracks you marked, not just the most obvious
What the results mean
Read the outcome honestly, and let a change act as the trigger rather than the crack's mere existence.
- Stable width, flush faces, dry: nothing needs doing, and this is the common result
- Small seasonal change that returns to baseline: normal Calgary behaviour
- Growth that persists or accumulates across seasons: worth a professional assessment
- Any new horizontal crack, displacement, or visible bowing: assess promptly
Measure at the same point, every time
Width varies along a crack, so a measurement is only meaningful if it is taken at the same reference point on every visit. Pick one identifiable spot, mark it, and always measure there, otherwise a slightly different vantage gives a false impression of movement.
Alongside width, check the offset: whether one side of the crack sits proud of the other. Run a straightedge or your finger across the crack and note whether the faces are flush. A crack that was flush and is now displaced, or a corner that has stepped, is a more specific sign of movement than width alone.
- Mark the exact measurement point with the date and reuse it on every visit
- Photograph from the same angle and height, with the same scale object in frame, so the images stack for comparison
- Record width at the same point and whether the faces are flush
- Note nearby doors and windows and whether they stick, and whether floors still feel level
Questions people actually ask
How do I know if my foundation crack is getting worse?
Mark the ends in pencil with the date, measure and photograph the widest point with a dated scale, and re-check in three to six months and after the spring melt. Growth against that recorded baseline is what tells you it is worsening, not memory or how it looks.
Will a foundation crack get worse over time?
Many do not. A crack that is stable, flush and dry commonly stays that way. Others get worse, and the ones that do are usually driven by an ongoing cause such as water or soil movement. That is exactly why monitoring exists: it separates the stable from the moving before the moving one becomes expensive.
How often should I check my foundation for cracks?
Once a baseline is set, re-checking every three to six months and again after the spring melt is enough for a stable-looking crack. You are looking for change, so the schedule matters less than always comparing against the recorded baseline.
When does crack monitoring mean I should call someone?
When growth against your baseline accumulates across seasons, or when a structural marker appears: a horizontal crack, displacement, a visible bow, or water following the crack. At that point monitoring has done its job and a professional assessment takes over.
How do I tell a new crack from an old one?
Age is read from finish and surroundings rather than guessed. A fresher crack tends to have sharper, cleaner edges, while an old one is often dust-stained, efflorescence-coated on the surfaces, or partly sealed by colour change. The reliable test is not looks but change: document it with a date, and if it is new, the next matter is whether it is growing. New alone is not a verdict.
Why did my foundation crack change after winter or the spring thaw?
Seasonal water is the usual driver in Calgary. Freeze-thaw works on existing cracks as water freezes in them, and spring melt loads the soil and drainage, so a crack can widen or leak during the cold season and re-stabilize in summer. A crack that moves only seasonally and returns to baseline is often normal; persistent or accumulating change is the reason to involve a professional.
How do I measure a foundation crack's width?
Measure the widest point with a steel ruler or callipers in millimetres and record the number with the date, alongside a dated photo with a scale in frame. Use the same point each time, because width varies along a crack. Repeat measurement at the same reference point is what makes the comparison meaningful.
Is monitoring ever the wrong approach?
Yes. Monitoring is only for tracking change over time. If a wall is already visibly bowing, a crack is displaced or growing rapidly, floors are sloping in a cluster, or there are horizontal cracks with displacement, monitoring is not the right answer and a professional assessment should come first. Monitoring buys information for stable or slow situations; it is not a substitute for acting on an obviously structural reading.
Want someone to look at your specific case?
General guidance only goes so far. Send a description and a postal code and it goes to an independent Calgary foundation contractor.
We are a referral service, not a contractor. Your request goes to an independent Calgary foundation company.