Can rain penetrate a cavity wall?
Weathering defects and cavity bridging can allow moisture past the outer leaf.
Read guide →DampUK practical guides
Walls, windows and doors
Walls and openings are designed to manage rain, not simply block every drop at the outer surface. Details around openings and cavities matter.
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Questions answered in this section
Can defective cavity trays cause damp?
Missing or poorly detailed trays can direct water inward at openings and roof junctions.
Read guide →Why is water getting in around my windows?
Check perimeter joints, sill detailing, cavity trays and condensation separately.
Read guide →Can cracked rendering cause damp?
Render cracks can admit rain, although moisture may have other entry routes.
Read guide →Do missing weep holes cause damp?
Weep openings help drain some cavities, but their absence is not proof of a defect in every wall.
Read guide →Why is water coming under my external door?
Threshold height, seals and paving levels all affect wind-driven rain entry.
Read guide →Can a leaking window sill cause internal damp?
An incorrectly sloped sill or failed end dam may return water into the wall.
Read guide →Why is the wall and ceiling junction wet?
Investigate roof and wall abutments, concealed services and cold bridging.
Read guide →Can pointing allow rain through brickwork?
Failed mortar joints may increase exposure, but repointing alone will not fix all damp.
Read guide →Why is one side of my house damp after storms?
Prevailing wind, exposed elevations and facade details help explain differences.
Read guide →Can cavity wall insulation cause damp patches?
Poor installation, exposed locations and existing defects must be evaluated before blaming insulation.
Read guide →Why does damp form beneath a window?
Consider cold bridging, condensation, sill leakage and cavity tray defects.
Read guide →Can an external crack admit rainwater?
Cracks may admit moisture but their position and depth determine significance.
Read guide →Can blocked cavity weep holes cause leaks?
Blocked drainage routes may trap water above openings in some wall designs.
Read guide →Can a leaking door canopy cause damp?
Failed junctions and wall fixings may direct water behind the canopy.
Read guide →Why is plaster damp beside a chimney breast?
Flashing defects, salts and flue condensation each produce different patterns.
Read guide →Can new windows increase condensation?
More airtight replacements can change ventilation and surface temperature conditions.
Read guide →Why are internal walls damp after external rendering?
Trapped moisture and inadequate detailing may be involved; diagnosis depends on construction.
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