COST GUIDES
External wall insulation cost: 2026 UK guide
Updated 06/26
External wall insulation costs for a typical UK home can vary widely, depending on the property's size and the chosen finish.
This guide covers 2026 prices per square metre, by property type, and every factor that affects your final quote.
Fast Facts
The cost of external wall insulation for a mid-terrace house starts from £6,000
A large detached can reach £30,000 or more
Average installed cost: £175 per m²
You may be eligible for green grants to help with the costs
Hiring an MCS-certified tradesperson is essential
How much does external wall insulation cost?
| Cost provided item | Cost+VAT (Lower range) | Cost+VAT (Higher range) | Average cost |
|---|---|---|---|
| Detached | £20,000 | £30,000 | £25,000 |
| Semi-detached | £14,000 | £20,000 | £17,000 |
| Mid-terrace | £6,000 | £10,000 | £8,000 |
| Mid floor flat | £5,000 | £7,000 | £6,000 |
| Detached bungalow | £15,000 | £21,000 | £18,000 |
| Total installed cost per m² | £150 | £200 | £175 |
| Cost to remove external wall insulation (per m²) | £30 | £40 | £35 |
| EPS total installed cost per m² | £145 | £195 | £170 |
| Mineral wool total installed cost per m² | £155 | £205 | £180 |
| Foil faced insulation boards total installed cost per m² | £150 | £200 | £175 |
| Phenolic foam total installed cost per m² | £150 | £200 | £175 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
Data verified by our professional estimators
Estimators are CIOB & RICS members
The cost of external wall insulation varies depending on the size of your home, the material chosen, and the finish applied. Quotes start at around £6,000 for a mid-terrace house and can reach £30,000 or more for a large detached property.
But before we dive deeper into the costs, let's clarify exactly what external wall insulation is and how it differs from internal wall insulation.
Use these figures as a guide when comparing quotes. A wide range of prices from different installers on the same job is usually a sign that specifications differ. That's why it's important to check exactly what each quote covers before hiring.
What is external wall insulation?
External wall insulation is a system that fixes insulation boards to the outside of your home's walls, then covers them with render or cladding to seal and weatherproof the surface.
A certified insulation installer uses a two-step process. First, insulation is fixed to the exterior walls using mechanical fixings and adhesive. Next, render or cladding goes on top to seal the insulation.
It's an approach many homeowners prefer over insulating internal walls because it's more straightforward to install. It also won't reduce the size of a room (internal insulation can bring a wall in by around four inches).
One of the biggest cost factors is the type of material used. Options include:
Expanded polystyrene (EPS) boards
Mineral wool
Foil-faced boards
Phenolic foam
The finish you choose (render, cladding, or brick slips) also affects the final price. More on both below.
If you're thinking about wider home energy upgrades, see our guide to retrofit insulation for a whole-home view.
External wall insulation cost per m²
Most installers price external wall insulation per square metre of external wall area. The total installed cost (insulation board, fixings, render or cladding, and labour) runs from £150 to £200 per m², with an average of £175 per m².
Installers quote per square metre rather than per hour because the focus is on completing the job to the required standard, not on working a set number of hours.
External wall insulation cost by property type
The bigger the property, the more external wall area needs covering and the higher the total cost. As a general guide:
Mid-floor flat: costs range from £5,000 to £7,000
Mid-terrace house: costs range from £6,000 to £10,000
Semi-detached house: costs range from £14,000 to £20,000
Detached bungalow: costs range from £15,000 to £21,000
Detached house: costs range from £20,000 to £30,000
External wall insulation cost: job estimator tool
Looking for an instant estimate based on your exact property size? Give our cost calculator tool a try.
Job Estimate Calculator
Or, for an exact quote, download our mobile app to connect with external wall insulation installers we've checked and reviewed in your local area.
How long does external wall insulation take?
How long external wall insulation takes depends on the property size. Here's some average timescales, from the first day of scaffolding to final inspection:
Semi-detached house: five to ten working days
Mid-terrace home: three to five days
Detached property: two weeks or more
The bulk of the time goes on scaffolding erection, board fixing, and render or cladding drying time.
For an accurate timescale, you're always best off speaking to an installer directly.
Find checked and reviewed tradespeople
Make sure your walls are in good repair before installation begins. If the brickwork needs attention, see our repointing cost guide first.
Factors affecting the cost of external wall insulation
The per m² figures above give you a starting point, but several factors will push your final quote up or down:
1. Planning permission
Most external wall insulation jobs fall under permitted development rights and don't require planning permission. Listed buildings and properties in conservation areas are the main exceptions.
Always check with your local planning authority before work starts. See our planning permission cost guide for full details.
2. Materials
The type of insulation board affects both the thermal performance and the price:
Expanded polystyrene (EPS): One of the most widely used options. Installed cost: £145 to £195 per m²
Mineral wool: Good fire performance and the default recommendation for buildings over 11m high following updates to building regulations. Installed cost: £155 to £205 per m²
Foil-faced insulation boards: Reflective boards that perform well in thin profiles. Installed cost: £150 to £200 per m²
Phenolic foam: High thermal performance in a slim board. Installed cost: £150 to £200 per m²
For readers wanting to understand the technical side of insulating solid brick walls, our Ask-a-Trade guide covers the practicalities.
3. Scaffolding
External wall insulation requires scaffolding around the property. Most contractors include this in their quote, but not all, so double-check before you accept a price.
If scaffolding isn't included, see our scaffolding cost guide for typical rates.
4. Location
Prices vary across the UK. London and the South East tend to be considerably more expensive than other regions, both for materials delivery and labour rates.
Always get several quotes from local insulation contractors to get a realistic picture for your area.
5. Finish and render type
The render or cladding you choose adds to the overall cost and affects the look of your finished home. Silicone render is the most popular choice.
The render or cladding average cost is included within the per m² figures in the table above. But for a full breakdown of rendering costs, see our house rendering cost guide.
Additional costs to budget for
Here's some of the cost factors that can sometimes get forgotten when budgeting for external wall insulation:
1. Removing existing insulation
If you're replacing existing external wall insulation, factor in the cost of removal. The average removal cost is £35 per m² (range: £30–£40 per m²).
2. Survey costs
All external wall insulation jobs should start with a thorough survey. Most reputable installers include this in their quote, but always confirm before signing on the dotted line.
3. Gutter and pipework removal
Installation often requires temporarily removing your existing gutters and other external pipework. See our gutter replacement cost guide for pricing.
Ways to save on the cost of external wall insulation
External wall insulation is a sizable investment (albeit an important one). Here's some tips to help you save on costs:
1. Time your job with other works
Schedule the work alongside other building projects that need scaffolding, such as roofing, chimney repairs, or solar panel installations. Sharing scaffolding between jobs cuts the overall cost of each one.
2. Grants and funding
You may be eligible for help through the ECO4 scheme, which can substantially reduce the cost of external wall insulation. Eligibility depends on your household income, your property's EPC rating, and where you live.
Check with your energy supplier or local council for the current offer in your area. Our green homes grant guide also has lots of information on the funding schemes available.
Green home grants available in 2026
Looking to make your home more eco-friendly and energy-efficient? Discover the latest green home grants that could help you save money while reducing your carbon footprint.
Pros and cons of external wall insulation
External wall insulation is more involved than other types of insulation, so weigh up the full picture before committing.
Pros of external wall insulation
Cons of external wall insulation
Solid wall vs cavity wall insulation cost
Solid wall insulation costs more than cavity wall insulation because there's far more labour, materials, and scaffolding involved. Let's look at the price difference:
Cavity wall insulation fills the existing gap between two leaves of brickwork and typically costs £2,700 for a semi-detached property
External solid wall insulation for the same property runs from £14,000 to £20,000, roughly five and seven times more
If your home was built before 1920, you'll very likely have solid walls. External insulation is the recommended approach because it avoids reducing your room sizes.
How to find an insulation installer
Use our quick and easy request a quote feature, and we'll get experienced local insulation installers to contact you directly. To get accurate quotes, be as detailed as you can:
The type of property (detached, semi-detached, terrace, or flat)
Whether you need existing insulation removed first
Your preferred finish (render, cladding, or brick slips)
Whether any grants or funding apply to your situation
Any access issues such as narrow side passages or listed building status
Keen to speak to someone right away? Contact insulation contractors local to you below:
Find an insulation installer covering your local area
Enter your postcode to find a top tradesperson near you
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External wall insulation cost checklist
External wall insulation cost checklist
Before contacting a tradesperson, here's what to check:
External wall insulation cost FAQs
A semi-detached home typically takes five to ten working days from scaffolding up to final inspection. A mid-terrace can be done in three to five days; a larger detached property may take two weeks.
The total installed cost for external wall insulation, including insulation boards, fixings, and render or cladding, runs from £150 to £200 per m² , with an average of £175 per m². EPS (expanded polystyrene) is at the lower end, while mineral wool runs a little higher.
For most solid-walled homes, external wall insulation is a worthwhile investment. It reduces heat loss significantly, lowers heating bills, and can improve your EPC rating. The payback period is long (15-25 years), so grants like the ECO4 can make a real difference to the sums.
Most external wall insulation jobs fall under permitted development and don't need planning permission. Listed buildings and homes in conservation areas are the main exceptions, so always check with your local planning authority before starting work.
Expanded polystyrene (EPS) is typically the most affordable option, installed at £145-£195 per m². Phenolic foam and foil-faced boards are in the same range. Mineral wool costs a little more at £155-£205 per m² but offers the best fire performance.
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