Cavity Wall Damp

Cavity Wall Damp
Penetrating damp

Cavity Wall Damp

Cavity wall damp work traces rain that reaches the inner leaf of UK cavity houses through mortar, insulation or failed ties. It is for isolated patches after wet weather, not a tide mark from groundwater. Paint on the inside does not clear the cavity. Request a quote with the form or WhatsApp.

A cavity should break the rain path. Mortar droppings, insulation and corroded ties can carry water to the inner leaf.

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Symptoms

What people notice first

Isolated internal patches that line up with rain on one elevation

Damp above the damp proof course that is not a tide mark

Wet insulation, mortar on the cavity tray, or rusty wall ties

A stain under a window where the cavity is bridged

What's included

  • Pattern of internal staining mapped
  • Cavity checked where access allows
  • Bridging and tie condition noted
  • A repair aimed at the bridge, not a surface paint
  • Extract or drying if the inner leaf is saturated

What this visit does not do

  • We do not strip all cavity insulation as a default
  • We do not inject the inner leaf and leave the bridge in place
  • A full external reclad is outside this visit unless it is specified as the rain path
Method

How the visit runs

Internal patches are mapped against the elevation. Where access allows, the cavity is checked for mortar droppings, debris, saturated insulation and failed ties or trays. The repair clears the bridge or the failed detail. If the inner leaf is saturated it is dried. Internal waterproof paint is not the repair.

1

Investigate first

We map the stain, take moisture readings, check salts where plaster has blown, and look outside at ground levels, gutters, pointing and the damp proof course line. The damp type is written down before any treatment.

2

Treat the path that is wet

Rising damp, rainwater, condensation, a bridged cavity or a wet cellar each get the repair that closes that path. A damp proof course is used only where groundwater is the cause.

3

Leave a record and a drying time

You get a treatment record and the guarantee that applies to the system installed. Plaster and paint wait until the readings say the wall is ready. Decorating a wet wall brings the mark back.

4
What changes the price

Quotes follow how much of the wall is bridged, the height of the work, and whether insulation has to come out.

5
After the visit

Keep sills and cavity trays clear. Do not raise outside ground over the tray. Watch the same patch in the next spell of wind-driven rain.

6
What fails if this is skipped

Debris left in the cavity brings the same stain back. A cleared, sound cavity stays dry on that path.

Internal damp paint on the inner leaf leaves the water in the cavity. The patch returns beside the painted area.

FAQ

Questions

These are the questions for this job. Wider damp questions sit on the FAQ page.

All FAQs

No. Rising damp is groundwater from the base of the wall. Cavity damp is water crossing from the outer leaf, usually in rain, because something bridges the gap.

It can, if it is slumped, saturated, or was installed so that it bridges the cavity. Insulation that is doing its job is not removed for the sake of it.

Through a small opening where the stain and the construction allow a look. We do not guess the cavity from the paint colour inside.

Only the material that is bridging or holding water. The quote says how much, after the cavity has been seen.
Related

Other services

Penetrating Damp Solutions
Expert Damp Surveys & Diagnosis
Rising Damp Specialist Treatment
Condensation Management Systems
Coverage

Areas we cover

The same survey runs in these counties, and across the rest of the UK.

Greater London Greater Manchester Kent Devon Cardiff Edinburgh
See all areas we cover
Next step

Your building, diagnosed before it is treated.

Damp from bridged cavities, failed wall ties, or soaked insulation.

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