Identify leak pathways using a clear weighted scoring. Compare assemblies, joints, and exposure quickly onsite. Make targeted upgrades that keep interiors dry for years.
| Scenario | Rain (mm/hr) | Wind (km/h) | Exposure | Sealant | Drainage | Crack (mm) | Typical score | Category |
|---|---|---|---|---|---|---|---|---|
| Sheltered retrofit | 10 | 15 | Sheltered | Good | Continuous | 0.10 | 18–28 | Low |
| Urban midrise | 25 | 35 | Normal | Fair | Partial | 0.25 | 42–55 | Moderate |
| Coastal corner | 45 | 60 | Coastal | Poor | None | 0.70 | 75–88 | Critical |
This calculator uses a weighted risk index. Each input is converted to a subscore from 0 to 10. The final score is a weighted sum scaled to 0–100.
Water penetration risk increases when exterior wetting loads exceed an assembly’s ability to shed, drain, and dry. This calculator combines climate inputs with observed detailing condition to produce a repeatable screening score. Use it to prioritize inspections, compare elevations, and document why certain repairs should lead the scope. It is especially useful during preconstruction surveys, due diligence, and recurring leak investigations across multiple facade zones.
Higher short-duration rain intensity raises surface wetting and runoff concentration. Wind speed and exposure raise pressure differences that push water through joints, cracks, and interfaces. Windward orientations typically experience the highest rain deposition. Normalizing units allows teams to enter regional weather values consistently across projects. Consider seasonal storm direction and local turbulence around corners and parapets.
Porous substrates can absorb water and keep it available near joints for longer periods. Veneers and renders may store moisture behind finishes, especially where drying is limited. Selecting a wall system and porosity rating helps estimate how quickly incidental water can migrate to sensitive layers, openings, and interior finishes. Where salts, freeze-thaw, or corrosion are concerns, repeated wetting cycles can accelerate damage.
Most leaks originate at transitions: window perimeters, coping joints, shelf angles, and service penetrations. Sealant condition and joint detailing reflect the quality of the primary water control line. Flashings, a drainage plane, weep paths, and membrane continuity represent secondary defenses. Redundancy lowers consequence when the primary line is imperfect. If drainage is blocked, even small defects can create sustained wetting and hidden interior damage.
Age, crack width, and maintenance frequency influence degradation of sealants and movement control. The output highlights top contributing factors and provides targeted actions, supporting a maintenance plan with measurable priorities. Exported CSV and PDF reports help track conditions over time, compare post-repair scores, and communicate risks to stakeholders. Pair the score with photos, moisture readings, and repair logs for stronger decisions.
It is a comparative screening index from 0 to 100. It summarizes wetting load and enclosure resilience based on your inputs. Use it to rank elevations and scope investigations, not to certify watertight performance.
Rain intensity, wind effects, porosity, joint detailing, and crack width carry higher weight. Poor sealant, missing flashings, and blocked drainage can also dominate results when selected.
Use short-duration peak rain intensity and a representative wind speed for storm events. If you have local design data, use that. Otherwise, use conservative field estimates and revise after site observations.
No. Leaks can still occur from isolated defects, poor workmanship, or unusual events. A low score means conditions are generally favorable, but targeted checks at openings, corners, and penetrations remain important.
Start with source control: repair sealants, add flashings, and restore continuity at transitions. Improve drainage and weep paths, then confirm membrane laps. After repairs, recalculate to document improvement and plan maintenance.
If the score is High or Critical, or if leaks are active, consider diagnostic openings, hose testing, or other field methods. Testing is also useful before major repairs to confirm mechanisms and avoid repeating the failure.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.