- External Wall Insulation
External Wall Insulation Surveys
Has damp appeared since your external wall insulation was fitted? Or are you buying a home with an existing system and need to know it was installed correctly? An external wall insulation survey gives you an independent answer. Our surveyors inspect the render, junctions, ventilation and services, then explain what is wrong, how serious it is and what should happen next. Fitzgerald Surveying Services carries out EWI inspection surveys across South East England.Ā
- Independent, qualified surveyors who are members of RICS, RPSA, CIOB and FODCS
- 5-star rated from 67 Google reviews
- Non-intrusive inspections supported by thermal imaging and moisture readings
- Clear reports that can support discussions with installers and sellers
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- About External Wall Insulation
What Is an External Wall Insulation Survey?
External wall insulation, or EWI, is usually fitted to homes with solid walls. With no cavity to fill, the insulation goes on the outside instead, as boards finished with render or cladding. The results can be excellent. When the work falls short, though, the first clue is often a damp patch inside, sometimes years later.
An external wall insulation survey looks closely at how the system was put together. Our surveyor checks the render, the trims and beads, and every point where the insulation meets a window, door, roofline or the ground. Thermal imaging picks up missing boards and cold spots. Moisture meters test the walls from inside, and a drone covers high-level detail that cannot be seen safely from below. Some clients know it simply as an external wall survey.Ā
Independent inspection matters more now than it once did. In 2025, the National Audit Office found that around 98% of homes given external wall insulation under the government’s Energy Company Obligation schemes had major issues needing repair. An independent inspection gives owners and buyers evidence they can act on, rather than assurances from the original installer.Ā
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- External Wall Insulation Findings
Common External Wall Insulation Defects We Identify
No two installations are identical, yet the defects we find tend to follow familiar patterns. Most arise at the edges of the system, where it meets other parts of the building, rather than in the insulation boards themselves.
Water Ingress and Render Failure
Render is the first line of defence against the weather. Cracks, blown patches and poorly sealed joints allow rainwater behind the finish, where it can saturate the insulation and the wall beneath. Staining, algae growth and hollow-sounding areas are common warning signs. Left unaddressed, trapped moisture can eventually reach the inside of the property as damp and mould.
- Cracked, blown or debonded render identified
- Staining and algae patterns recorded
- Signs of water behind the finish assessed
Poor Detailing Around Openings and Junctions
Junctions are where installations most often fail. Uninsulated window reveals, missing or badly fitted trims, eaves that no longer cover the added wall depth, and insulation carried below the damp proof course all create routes for water and cold. These details are easily overlooked during installation, yet they largely decide how well the whole system performs over time.
- Window, door and reveal detailing checked
- Eaves, verges and roof overhangs assessed
- Base details and damp proof course bridging reviewed
Blocked Ventilation and Affected Services
Adding insulation to an external wall affects everything fixed to it. Boiler flues, airbricks and extractor outlets need to be properly extended through the new layer, and cables, pipes and meter boxes must be safely accommodated. Where this has been missed, the result can be inadequate ventilation or a genuine safety concern. These are among the most urgent matters we report.
- Boiler flues and ventilation outlets checked for obstruction
- Airbricks and sub-floor ventilation reviewed
- External cables, pipes and meter boxes noted
- Report Overview
What's Included in Your External Wall Insulation Survey Report
Your report sets out what we found, how serious each issue is, and what should happen next. Every finding is supported by photographs and, where relevant, thermal images, so the evidence is clear both to you and to anyone else who needs to review it.
- Overview of the External Wall Insulation System
- Photographs of Each Elevation and Key Details
- Thermal Images Showing Gaps and Cold Spots
- Render, Trim and Junction Observations
- Ventilation and Services Assessment
- Internal Moisture Readings Where Relevant
- Defects Graded by Seriousness
- Recommendations for Repair or Further Investigation
- Professional Opinion on the Overall Condition of the System
- Why Choose Us
Why Choose Our EWI Defect Surveyors
When external wall insulation goes wrong, the company that fitted it is not always best placed to judge it. As an independent EWI defect surveyor, Fitzgerald Surveying Services has one interest: an accurate account of the installation. Our surveyors are members of RICS, RPSA, CIOB and FODCS (Federation of Damp Certified Surveyors). An external wall insulation survey is not itself a RICS-accredited survey type; each inspection is nonetheless carried out by a qualified surveyor working to recognised professional standards.
Independent Perspective
We do not install, repair or guarantee external wall insulation, and we have no commercial ties to firms that do. Our findings are never shaped by who might carry out the remedial work.
Evidence You Can Rely On
Each defect is photographed, located and explained in plain terms. That record can support conversations with an installer, a guarantee provider or a seller.
Building-Focused Assessments
External wall insulation behaves differently on a Victorian solid brick terrace than on a post-war system-built house. Our experience with damp and moisture problems helps us read each installation in the context of the wall behind it.
Clear and Structured Reporting
Findings are grouped by elevation and ranked by urgency, so you can quickly see which issues need attention first.
- Service Area
External Wall Insulation Surveys Across South East England
We carry out external wall insulation surveys throughout Buckinghamshire, Hertfordshire, Surrey, Oxfordshire, Bedfordshire and Berkshire, for both residential and commercial properties.
Buckinghamshire
Hertfordshire
- Client Feedback
What Clients Say About Fitzgerald Surveying
Clients often tell us they valued a straight answer about what had gone wrong and what to do next. Their feedback on working with Fitzgerald Surveying Services is shown below.
- Our Process
From Booking to External Wall Insulation Report in 4 Clear Steps
Whether damp has appeared since the insulation was fitted or you simply want reassurance before buying, the process is straightforward.
STEP 1
Discuss Your Concerns
Tell us about the property, when the insulation was installed, and anything you have noticed since, such as cracking, staining or damp patches inside.
STEP 2
Arrange a Suitable Inspection Date
We agree on a date that suits you. Any installation paperwork or guarantee documents you hold are useful to have available on the day.
STEP 3
External Wall Inspection
Our surveyor inspects each elevation and the related internal areas, using thermal imaging, moisture meters and, where needed, drone imagery.
STEP 4
Receive Your Survey Report
Your report is delivered digitally, with photographs, thermal images and clear recommendations on the next steps.
- FAQ
External Wall Insulation Survey Questions, Answered
Some clients contact us because damp has appeared since their insulation was fitted. Others are buying a home with an existing system and want to understand what they are taking on. These are the questions we are asked most often.
It is an independent, non-intrusive inspection of the insulation system fixed to the outside of a building. The surveyor checks the render, trims, junctions, ventilation and services, and looks for signs of water getting behind the finish. The findings are set out in a written report with photographs and recommendations.
Outside, look for cracked or bulging render, dark staining or algae, gaps around windows and doors, and trims that have come loose. Inside, the usual signs are damp patches, mould or condensation on walls that were dry before the work was carried out. Any of these is worth investigating before the problem spreads.
Most problems stem from poor detailing and workmanship rather than the materials themselves. The National Audit Office linked the widespread failures under recent government schemes to weak controls and oversight, with a possible shortage of skilled installers also playing a part. Junctions, openings and services require the most care, and these are the areas most often rushed.
No. An EWS1 form relates to the fire safety of external wall systems, usually on blocks of flats, and is often requested by mortgage lenders. It must be completed by an appropriately qualified professional under an agreed industry process. Our external wall survey focuses on installation quality, water ingress and moisture, and does not produce an EWS1 form.
Yes. Under the Energy Company Obligation, the original installer is responsible for putting faults right, with TrustMark overseeing the process of finding and fixing affected homes. An independent report gives you a clear record of the defects present, which can be useful when raising concerns or checking that remedial work has been completed properly.
It is a sensible step if the property has external wall insulation. Standard RICS Home Surveys do not fully inspect these systems, so defects behind the render can go unreported. A dedicated survey before exchange tells you whether the installation is sound, or whether repairs should be reflected in the price.
No. The inspection relies on visual assessment, thermal imaging, moisture meters and, where useful, drone imagery. Nothing is cut, drilled or removed. If a defect can only be confirmed by opening up part of the system, we explain this in the report and recommend how it should be investigated.
The cost depends on the size of the property, the number of elevations and how accessible they are. Please contact us for a no-obligation quote based on your specific circumstances.
Get In Touch
Buying a property? Get independent advice before you commit. Our RICS surveyors provide clear, detailed reports through Level 1 Condition Surveys, Level 2 Homebuyer Surveys, and Level 3 Building Surveys, helping you identify potential defects and make a more informed purchase decision. Contact our team today for expert property survey advice.
63 New Road, Weston Turville, Aylesbury HP22 5QY
enquiries@fitzgeraldsurveying.co.uk
0333 2249 516