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Harrow · Greater London

Damp investigation after cavity insulation in Harrow

A damp investigation finds out why an insulated wall is showing damp or mould: rain getting in through defects, bridged or wet fill, debris in the cavity, a breached damp-proof course, or condensation. We cover Harrow and the wider HA1 postcode district, and the price is confirmed before anyone visits.

Book a damp investigation in Harrow

Covering Harrow and the HA1 district. Tell us about the property. We confirm the price before you book.

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We use your details only to answer this enquiry and arrange your visit, sharing them only with the registered installer we appoint for your job and the providers named in our privacy notice. No marketing lists, no cold calls.

Damp investigation after cavity insulation for Harrow properties

Our Greater London coverage takes in Harrow (HA1) and nearby Wembley, Northolt and Greenford. It is roughly 10 miles north-west of London.

We never cold-call in Harrow or anywhere else, and we do not work with doorstep claims companies. Damp in an insulated Harrow home is not always the insulation's fault, so the diagnosis comes before any extraction.

Wind-driven rain is the first thing the surveyor weighs up. Much of Greater London sits in the more sheltered driving-rain zones of the UK, which widens the choice of fill. Exposed elevations, coastal sites and high ground still get checked wall by wall.

On compliance, if cavity wall insulation follows in Harrow, filling a cavity is notifiable building work and needs a building notice or competent-person self-certification.

Rules in England

Filling a cavity is notifiable building work and needs a building notice or competent-person self-certification if insulation work follows.

Sources: Planning Portal: cavity wall insulation and building regulations; CIGA: CWISC competent person scheme.

Common causes we check

Defective pointing, cracked render and porous bricks letting rain in; leaking gutters and downpipes; fill bridging the cavity where mortar droppings or debris have collected; ground levels above the damp-proof course; and condensation from cooking, drying clothes and too little ventilation.

What is included in Harrow

  • Moisture mapping inside
  • Borescope at affected areas
  • Cause and options in writing
  • External defects check

Guide prices for Harrow

Damp investigation after cavity insulation guide prices
Damp investigation after cavity insulation guide pricesGuide price
Damp investigation with borescope£295–£495

This work is not insulation, so it is normally standard-rated for VAT. Guide prices include VAT where it applies. Guide ranges only: the fixed price is confirmed in writing before any work starts, and anything that could not be seen at survey is agreed with you first.

What happens next for a Harrow property:

  1. Get in touch

    Online, by phone or WhatsApp.

  2. Your price

    Confirmed in writing before you book.

  3. The visit

    Carried out at an agreed time, with photos of what we find.

  4. Your report

    Plain English, with any follow-on work quoted separately.

Last reviewed 19 October 2026.

Damp investigation after cavity insulation in Harrow: questions

How much does a damp investigation cost in Harrow?

Guide prices are shown on this page, and the price for your Harrow property is confirmed before you book.

Is there VAT on a damp investigation in Harrow?

Damp investigation after cavity insulation is not insulation, so it is normally charged at the standard rate of VAT. The VAT treatment is confirmed on your quote.

Will you tell me if I do not need any work?

Yes. If the findings show nothing needs doing, or a cheaper fix such as clearing a gutter will do, we say so.

Do you cover Harrow?

Yes. Harrow and the HA1 postcode district are within our Greater London coverage, along with nearby Wembley and Northolt.

Nearby towns

Book a damp investigation in Harrow

Priced before you book. Findings in writing. No cold calls.