Window perimeter leakage

A practical decision sequence

Diagnose the cause, then verify the repair.

Use the site evidence to agree a project-specific method with the responsible engineer, concrete producer, manufacturer or specialist applicator.

01 / Symptom

What is happening?

Water appears around a frame during wind-driven rain.

02 / Inspect and test

Evidence to collect

Check sill slope, weep holes, flashing, frame-to-wall joint and glazing drainage.

03 / Likely mechanism

Why it can fail

Blocked weeps or missing sill and perimeter detailing can bypass façade coating.

04 / Technical response

Choose the system

Repair sill and flashing, preserve drainage and renew a compatible perimeter joint.

05 / Site execution

Control the application

Clean bond faces and apply backing, primer and sealant per system design.

06 / Acceptance

Verify the result

Spray test progressively from lower to upper zones to isolate entry.

Avoid this shortcut

Do not seal intended drainage or weep openings.

These guides are editorial starting points, not a project specification. Confirm the design, product data, substrate conditions and inspection plan for the actual site.

Technical references

References inform the topic; they do not endorse a specific product for this project.