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What's the Difference Between a Damp Survey and a Structural Survey?

A damp survey costs £150–£400 and identifies moisture sources (rising damp, penetrating damp, condensation) with treatment recommendations. A structural survey costs £600–£1,800 and assesses load-bearing fabric, movement, foundations and roof structure. Damp surveys focus on remedial treatment; structural surveys inform extension design and risk. Many London renovations need both.

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What a damp survey covers

Carried out by a CSRT or CSSW-qualified surveyor (Certified Surveyor in Remedial Treatment or Construction in Structural Waterproofing). Covers: rising damp identification using calcium carbide meter or salts analysis, penetrating damp from external wall defects or roof leaks, condensation from ventilation and thermal bridging, mould growth and air quality. Output: written report with photographs, moisture readings at floor and wall samples, treatment specification with budget cost. Cost £150–£400 depending on property size. Useful for: pre-purchase due diligence, ongoing moisture issues, mortgage requirements, insurance claims.

02

What a structural survey covers

Carried out by a chartered structural engineer (MICE, MIStructE, CEng). Covers: foundation type and condition (strip, raft, piled), load-bearing wall identification, beam and lintel assessment, roof structure evaluation, settlement and movement assessment, suitability for proposed extension, structural calculations for any new openings. Output: written report with structural recommendations, design drawings if required, calculations to Building Regulations Part A standard. Cost £600–£1,800 depending on scope and property complexity. Required for: any extension involving new openings, removal of chimneybreasts, basement excavation, loft conversion structural design.

03

When you need both

Almost every London Victorian or Edwardian renovation needs both surveys. A side-return kitchen extension needs structural design (new RSJ openings, foundation interface, lintel sizing) plus damp investigation (lime plaster vs modern render compatibility, DPC continuity, ground floor moisture). A whole-house refurbishment needs structural (any wall removals, loft conversion suitability) plus damp (rising damp treatment, breathable wall buildup specification). Commissioning both at design stage avoids surprises at contractor pricing and reduces variation costs during the build.

More questions

Related questions answered.

Will my mortgage lender accept these surveys?

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Most lenders accept RICS Level 2 (Homebuyer Report) or Level 3 (Building Survey) — both cover damp and structural at headline level. For detailed remedial work or extension design, you'll need a specialist damp survey AND a structural engineer's report. The lender's Level 3 survey is a starting point, not a substitute.

Can my builder do the damp and structural assessment?

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No. Both surveys require specific accreditations (CSRT/CSSW for damp; MICE/MIStructE/CEng for structural) and independent professional opinions. Your builder can install treatment specified by these surveyors but should not be designing structural openings or specifying damp treatment themselves.

How long do the surveys take?

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Damp survey: 2–3 hours on site, 5–7 working days for written report. Structural survey: 2–4 hours on site, 7–14 working days for written report including calculations. Total turnaround typically 2 weeks for both. Plan surveys at the start of design stage, not after planning approval.

Does Builderr commission damp and structural surveys?

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Yes — at design stage on every renovation and extension. We commission CSRT damp surveyors and chartered structural engineers as required, coordinate their reports with the architectural design, and incorporate their specifications into the build contract. Independent surveys avoid conflict of interest.

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