Diagnostic guide
Damp after rain
Find out why internal damp worsens after rainfall and how Quay Point Plastering investigates likely entry routes.
Why diagnosis matters
Treat the cause, then repair the damage
A clear relationship with rainfall is valuable diagnostic evidence. The visible patch may sit below a failed gutter, beside a window, around a chimney or along a route hidden within the wall.
Complimentary survey
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Over 35 years of independent expertise. Written findings included. No sales pressure. No obligation.
Book your complimentary surveyTechnical review
Dan, Director / Surveyor
Last reviewed: July 2026. Advice is general until the property, access and visible evidence have been assessed.
Guarantee & aftercare
Written guarantee terms are matched to qualifying work, with inclusions, exclusions and aftercare explained before acceptance.
What we consider
Possible causes and lookalikes
Rainwater goods and roof junctions
Pointing, masonry and render defects
Openings, seals and cavity bridges
Ground drainage and splashback
Inspection method
A clear work sequence
Step 1
Review timing and exposure
Step 2
Inspect internal pattern
Step 3
Check accessible external defects
Step 4
Set a repair-and-drying sequence
Scope boundaries
Honest about what the work does—and does not—cover
High-level access, invasive cavity work, roof repair and drainage excavation are separately scoped or referred.
Complimentary specialist survey
Your Complimentary Specialist Survey
Backed by over 35 years of independent damp and timber expertise.
We believe in diagnosis before treatment. That's why we offer every homeowner and property manager in Dorset, Hampshire and Wiltshire a complimentary specialist survey — carried out by an experienced specialist, not a salesperson.
Over 400 combined reviews across Google and Checkatrade. Over 35 years protecting Dorset homes.
Common questions
About damp after rain
Can the water travel inside the wall?+
Yes. Water can move along cavities, joists and finishes before appearing. The nearest visible defect is not automatically the cause.
Should I paint over the patch?+
Not until the source is corrected and the substrate has dried. Early sealing can hide evidence and lead to repeat failure.
Can damp be diagnosed from photographs?+
Photographs can help us triage an enquiry, but they cannot confirm the moisture source. A site inspection allows the building context, weather exposure, ventilation and accessible materials to be considered together.
Is the specialist survey really free?+
Yes — completely. We offer every homeowner and property manager across Dorset, Hampshire and Wiltshire a complimentary specialist survey at no charge. This includes an on-site inspection, written findings, a clear scope of any recommended work, and an honest referral if the problem falls outside what we do. You pay nothing for the survey. You only pay if you commission the remedial work, and you are under no obligation to do so. The reason we do this is straightforward: we believe in diagnosing the problem before recommending a treatment. A proper inspection takes time, and we'd rather invest that time up front than quote a solution before we've understood the cause.
Not sure if this is your problem?
That's exactly what the survey is for. Book your complimentary specialist survey and one of our experienced team will identify the cause on-site, consider the alternatives, and give you written findings — at no charge and with no obligation.
Related services
Continue your investigation
Recent work
Photographed on our own projects
A selection of real jobs from this service, photographed on site across Dorset, Hampshire and Wiltshire.
Reviewed by local homeowners
Trusted across Dorset, Hampshire and Wiltshire
Independent feedback from customers on Google and Checkatrade — alongside over 35 years of damp proofing and plastering experience.
Next step
Claim your complimentary survey before choosing a treatment
Tell us what you can see, when it changes and where the property is. Photographs can help us triage the next step.