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Derry · County Londonderry

Cavity wall suitability survey in Derry

Before anyone drills in Derry, the walls are checked properly. The survey is free with an install quote; standalone reports are priced first. A cavity wall survey checks whether your walls can safely be filled and with what.

Book a survey in Derry

Covering Derry and the BT48 district. Free with an install quote; standalone reports are priced before you book.

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Cavity wall suitability survey for Derry properties

Derry sits in County Londonderry. We work across the BT48 district, including nearby Limavady, Coleraine and Magherafelt.

The written result for your Derry property is plain English: what we found, what it means and what, if anything, to do next. A survey in Derry gives you facts before anyone drills: what the wall is, what is in the cavity and whether it is sound.

Before any material is chosen, exposure is checked. Parts of County Londonderry face some of the heaviest wind-driven rain in the UK, especially exposed coastal and upland sites. Here the survey is stricter: some walls suit only certain certified systems, and some should not be filled at all.

In terms of approvals, in Derry inserting cavity wall insulation needs a building control application to the council before work starts.

Rules in Northern Ireland

Inserting cavity wall insulation needs a building control application to the council before work starts if insulation work follows.

Sources: Building Control NI: frequently asked questions; Belfast City Council: what are the building regulations.

What the surveyor checks

Wall construction and thickness at window reveals; cavity width and debris with a borescope; brickwork, pointing, render, sills, gutters and downpipes; signs of damp inside and out; air bricks and flues; joins with neighbours and extensions; and the exposure of each elevation to wind-driven rain.

What is included in Derry

  • Photo-backed written result
  • Cavity width and debris check
  • Repairs list where needed
  • Exposure assessment by elevation

Guide prices for Derry

Cavity wall suitability survey guide prices
Cavity wall suitability survey guide pricesGuide price
Suitability survey with an install quoteFree
Standalone survey report (no install quote)£145–£245

The survey is free with an install quote. A standalone report is not insulation, so it is normally standard-rated for VAT; guide prices include VAT. 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.

How it works in Derry:

  1. Tell us about the property

    Postcode, property type and why you need the survey.

  2. Survey visit

    Walls, cavity, condition and exposure checked and photographed.

  3. Written result

    Suitable, suitable after repairs, or not suitable.

  4. Fixed price if you want work

    The survey is free when it is for an install quote.

Last reviewed 19 October 2026.

Cavity wall suitability survey in Derry: questions

Is my Derry home too exposed for cavity insulation?

Parts of County Londonderry get some of the heaviest wind-driven rain in the UK, so the survey is stricter and some walls are better left unfilled. The survey records the exposure of each wall before recommending a material, or recommending against filling.

Do you cold-call in Derry?

No. We only come out when you have asked us to. If someone cold-calls offering free insulation, check before you agree to anything.

Is the survey free in Derry?

Yes when it is for an install quote. Standalone reports for Derry buyers, sellers or landlords who do not need an install quote are priced before you book.

Do you cover Derry?

Yes. Derry and the BT48 postcode district are within our County Londonderry coverage, along with nearby Limavady and Coleraine.

Nearby towns

Book a survey in Derry

Free with an install quote. Written result for every wall.