External Wall Insulation Survey: Professional Assessment Guide
Get a comprehensive professional survey of your external wall insulation to identify problems, assess damage, and determine the best course of action. Essential for insurance claims and compensation cases.
What Is an External Wall Insulation Survey?
An EWI survey is a detailed professional inspection of your external wall insulation system to assess its condition, identify defects, determine if problems are caused by the insulation, and recommend appropriate remediation.
Unlike the brief visual checks performed by ECO4/GBIS installers, a proper independent survey uses scientific testing equipment and follows rigorous assessment protocols.
Types of EWI Surveys Available
Basic Visual Survey
Visual inspection of EWI system condition, identification of obvious defects, photographic record, and brief written report.
- • Initial assessment before deciding next steps
- • Properties with obvious visible problems
- • Pre-purchase property inspections
- • No moisture testing or thermal imaging
- • May not be accepted as evidence for legal claims
- • Cannot definitively prove causation
Comprehensive Damp & Moisture Survey
Detailed inspection with moisture meter readings, humidity measurements, condensation risk assessment, and full written report with photographic evidence.
- • Properties experiencing damp or mould issues
- • Insurance claims requiring evidence
- • Contractor disputes about installation quality
- • Moisture meter readings at multiple points
- • Internal wall moisture levels
- • Ventilation assessment
- • 15-20 page detailed report
Full Building & Thermal Survey
Complete assessment combining structural inspection, thermal imaging, moisture testing, installation compliance check, and expert witness-quality report.
- • Legal proceedings and compensation claims
- • Properties with multiple or severe issues
- • High-value claims requiring robust evidence
- • Thermal imaging survey (infrared camera)
- • Full moisture profiling across property
- • Structural integrity assessment
- • Installation standard compliance check
- • Expert witness-quality report (30-50 pages)
- • Cost estimate for remediation
Specialist Testing Package
Focused technical testing for specific concerns: air quality, mould identification, asbestos testing, or other specialist analysis.
- • Mould species identification and spore count: £200-£400
- • Air quality assessment (VOCs, humidity): £150-£300
- • Asbestos sampling and analysis: £100-£250 per sample
- • Salt contamination analysis (efflorescence): £150-£300
What Surveyors Check During an EWI Survey
External Inspection
Visual Assessment
- Render condition and cracking patterns
- Fixing system integrity (mechanical fasteners)
- Water ingress points and staining
- Detailing around windows and doors
- Base/ground level installation quality
- Roof/eaves junction and weatherproofing
Technical Measurements
- EWI system thickness and type
- Render thickness and specification
- Fixing density and pattern
- External surface moisture readings
- Thermal bridging at junctions
- Compliance with manufacturer specifications
Internal Inspection
Moisture & Damp Analysis
- Internal wall moisture levels (multiple points)
- Relative humidity measurements per room
- Condensation risk assessment
- Penetrating damp vs condensation diagnosis
- Dew point calculation for each room
Damage Assessment
- Mould growth location and severity
- Plaster and decoration damage
- Window reveal and sill problems
- Ventilation adequacy
- Structural damage (if any)
Thermal Imaging (Premium Surveys)
Thermal imaging cameras detect temperature differences across wall surfaces, revealing:
- Cold Spots & Thermal BridgesAreas where insulation is missing, thin, or ineffective
- Moisture AccumulationDamp areas show as cooler than surrounding dry surfaces
- Installation DefectsGaps between boards, poor fixing patterns, junction failures
- Air Leakage PointsDraughts and air infiltration through EWI system
The Survey Report: What You'll Receive
A professional EWI survey report typically includes:
1. Executive Summary
Overview of key findings, severity assessment, and primary recommendations (1-2 pages)
2. Property Description
Details of property type, construction, EWI system specification, and installation date/scheme (1-2 pages)
3. Methodology
Explanation of survey methods, equipment used, testing standards followed, and any limitations (1 page)
4. Findings & Evidence
Detailed observations, measurements, test results, annotated photographs, and thermal images (5-20 pages)
5. Causation Analysis
Expert opinion on whether problems are caused by EWI installation, linking evidence to defects (2-5 pages)
6. Recommendations
Prioritized remediation options, estimated costs, and timeline for action (2-3 pages)
7. Appendices
Surveyor qualifications, equipment calibration certificates, technical standards referenced, photo gallery
Red Flags Surveyors Commonly Find
Installation Defects
Critical Issues
- •Insufficient or no base coat mesh reinforcement
- •Missing or inadequate mechanical fixings
- •No starter tracks or base profiles at ground level
- •Incorrect board thickness or specification
- •Poor window reveal detailing (thermal bridging)
- •Render applied before adhesive cured
Moderate Issues
- •Inadequate render thickness (below manufacturer spec)
- •Insufficient overlap of mesh at joints
- •Inconsistent board fixing pattern
- •Poor joint treatment between boards
- •Mixing incompatible system components
- •Inadequate curing time between coats
Design & Suitability Issues
- EWI Installed on Unsuitable Substratee.g., directly onto timber frame, non-load-bearing render, or deteriorated brickwork
- No Consideration for Existing Damp IssuesPre-existing moisture problems sealed in by impermeable EWI system
- Inadequate Ventilation ProvisionNo ventilation upgrades despite increasing airtightness and condensation risk
- Wrong System for ExposureStandard thin-coat render used in high-exposure coastal/exposed locations
Survey Costs and What's Included
| Service | Cost | Included |
|---|---|---|
| Call-out & Inspection | £150 - £300 | Travel, time on site (2-4 hours) |
| Report Writing | £200 - £400 | Analysis, photography, written report |
| Thermal Imaging | +£200 - £400 | IR camera, thermal report, annotated images |
| Lab Testing (if required) | +£100 - £300 | Mould/asbestos samples, lab analysis |
| Expert Witness (if needed) | +£500 - £1,500 | Court-ready report, expert testimony availability |
Choosing the Right Surveyor
Essential Qualifications to Look For
Questions to Ask Before Booking
- 1.Do you have specific experience with ECO4/GBIS failure cases?
- 2.Will the survey report be suitable for insurance/legal claims?
- 3.What testing equipment will you use? (moisture meters, thermal camera, etc.)
- 4.How long will the site inspection take and when will I receive the report?
- 5.Is the quoted price inclusive of all testing and report writing?
- 6.Can you provide expert witness services if needed for litigation?
- 7.Do you have professional indemnity insurance and what's the cover level?
What Happens After the Survey?
1. Review the Report (1-2 weeks after survey)
Your surveyor will send you a detailed report. Read it carefully and note:
- Severity of problems identified
- Clear statement on causation (is EWI to blame?)
- Recommended remediation actions
- Estimated costs for repairs/removal
2. Discuss Findings with Surveyor
Most surveyors include a follow-up phone call or meeting to explain findings and answer questions. Use this to clarify anything unclear in the report.
3. Decide Your Course of Action
Minor Issues
If problems are minor and repairable:
- • Contact installer for remediation
- • Use report as leverage
- • Get repairs guaranteed
Moderate Issues
If significant defects found:
- • File formal complaint with Trustmark
- • Contact warranty provider
- • Consider legal advice
- • Obtain removal quotes
Severe Issues
If major failure confirmed:
- • Engage solicitor immediately
- • Notify all responsible parties
- • Get removal quotes
- • Prepare compensation claim
Survey Report Uses
A professional survey report can be used for:
- Insurance claims: Evidence for buildings insurance or legal expenses cover
- Contractor disputes: Proving defective workmanship or unsuitable installation
- Trustmark complaints: Formal evidence for scheme failure investigations
- Legal proceedings: Expert evidence in court cases against installers or schemes
- Remediation planning: Detailed specifications for contractors quoting removal work
- Property transactions: Disclosure to buyers or as evidence for renegotiating purchase price
Book Your Professional EWI Survey
We work with qualified, independent building surveyors who specialize in EWI failure assessment. Get an expert report that gives you the evidence you need for claims, disputes, or planning remediation.
Frequently Asked Questions
How long does an EWI survey take?
On-site inspection typically takes 2-4 hours for a standard house. Report writing takes 3-10 working days depending on complexity. Total turnaround is usually 1-2 weeks.
Do I need to be present during the survey?
Yes, surveyors need internal access to take moisture readings and assess internal damage. You should be present to explain the history of problems and provide any documentation.
Can the installer refuse to honor a survey report?
They may dispute findings, but a professionally-prepared report from a qualified surveyor carries significant weight in formal complaints and legal proceedings. Installers cannot simply ignore credible evidence.
Should I get multiple surveys?
Usually unnecessary and expensive. One comprehensive survey from a qualified surveyor is sufficient. Only consider a second opinion if the first report seems incomplete or you're pursuing high-value legal action.