Enter crack and site details
Example data table
| Width (mm) | Length (m) | Orientation | Displacement | Water | Bowing (mm) | Soil | Drainage | Score | Level |
|---|---|---|---|---|---|---|---|---|---|
| 0.8 | 0.6 | Vertical | None | Damp | 0 | Loam | Good | 22.1 | Low |
| 2.5 | 1.8 | Diagonal | Slight | Seepage | 8 | Clay | Average | 53.8 | High |
| 7.0 | 3.5 | Horizontal | Severe | Active leak | 30 | Clay | Poor | 86.5 | Critical |
Example scores are illustrative, based on the same weighting used in this page.
Formula used
The calculator assigns points to each factor and converts the total into a 0–100 score:
Higher points are applied to movement indicators (displacement, bowing) and water pressure drivers (moisture, soil, drainage). This keeps the score sensitive to conditions that often worsen quickly.
How to use this calculator
- Measure crack width and length in consistent units.
- Choose the closest match for orientation and displacement.
- Record moisture conditions during dry weather and after rain.
- Estimate bowing using a straightedge, string line, or laser.
- Fill in soil and drainage based on what you observe outdoors.
- Submit to get a score, level, and guidance above the form.
- Download CSV or PDF to store your inspection snapshot.
Why this score matters on real jobs
Foundation cracks are common, but risk rises when cracks show movement, water pressure, and soil expansion together. This calculator converts field observations into a repeatable 0–100 screening score based on a 104‑point weighting. It helps crews document site conditions, compare walls, and decide when to escalate to structural review. For consistency, use the same wall segment, measuring tools, and weather notes each time. Photograph the crack with a ruler, mark reference points, and note interior finishing that may hide movement. The score is conservative: if conditions are unknown, choose the higher-risk option and verify on site. Store exports with job numbers to support warranty discussions later.
Measurements that drive the strongest shifts
Crack width is grouped at <1 mm, 1–3 mm, 3–6 mm, and ≥6 mm, reflecting increasing loss of continuity. Crack length is grouped at <0.5 m, 0.5–1.5 m, 1.5–3 m, and ≥3 m to capture propagation. Wall bowing uses 0 mm, <10 mm, 10–25 mm, and >25 mm because deflection often correlates with lateral pressure.
Patterns that indicate pressure or settlement
Orientation adjusts the score because cracking geometry can signal different failure modes. Horizontal and stair‑step cracks generally score higher than vertical ones, especially when offset is present. Displacement is categorized as none, slight (≤3 mm), moderate (3–6 mm), or severe (>6 mm) to capture wall movement.
Water, soil, and drainage as multipliers
Moisture is scored from none to active leaking because water increases hydrostatic pressure and weakens soils. Clay and poor surface drainage raise the risk range, while sandy soils and good grading reduce it. Freeze‑thaw, nearby trees, and recent excavation add smaller increments that still matter on marginal walls.
Using results to plan next steps
Scores under 25 suggest monitoring and maintenance, 25–49 favors planned inspection and moisture control, 50–74 signals high risk and professional assessment, and 75+ warrants urgent evaluation. Recheck after storms, seasonal shifts, or new loads, and keep exports with dates to show trends over time.
FAQs
1) Is this a substitute for an engineer’s report?
No. It is a screening score to organize observations and prioritize follow-up. If bowing is growing, displacement is visible, or leaks are active, get a qualified structural evaluation.
2) Which inputs affect the score the most?
Displacement, wall bowing, moisture level, and crack orientation carry the strongest weight. Wide cracks and long cracks also increase the score quickly because they indicate propagation.
3) How should I measure bowing accurately?
Use a straightedge or string line across the wall face and measure the maximum gap in millimeters. Record the location so you can repeat the measurement at the same point later.
4) What if I have several cracks on one wall?
Score the worst crack, then run a second check for the average condition. If the worst score is high or rising, treat the wall as higher risk and document multiple locations.
5) Does cosmetic patching reduce risk?
Cosmetic patching may improve appearance, but it does not stop movement or water pressure. Use it only after drainage, waterproofing, and any needed stabilization are addressed.
6) When should I re-run the calculator?
Re-run quarterly, after heavy rain events, and after construction changes near the foundation. Comparing saved CSV/PDF exports helps confirm whether cracks are stable or progressing.