Mineral wool EWI · Mid Glamorgan
Mineral wool external wall insulation in Merthyr Tydfil
Mineral wool external wall insulation in Merthyr Tydfil: free survey, written specification and a fixed price, with the details that keep walls dry planned from the start. On blocks and taller buildings in Merthyr Tydfil, mineral wool is the default because of the fire guidance for external walls.
- Free survey in CF47 and nearby
- Guide price from £125 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Merthyr Tydfil
Postcode, service and a phone number is all we need.
Included as standard
- Used on blocks of flats and buildings with storeys above 11m
- Non-combustible board (typically Euroclass A1 or A2-s1,d0 as part of the system)
- Better sound reduction than foam boards
- Finished in mineral or silicone render, or brick slip
Before we quote in Merthyr Tydfil
We cover Merthyr Tydfil and nearby Aberdare, Rhondda and Ebbw Vale. It's roughly 7 miles from Merthyr Tydfil to Rhondda, the largest town in Mid Glamorgan. South Wales has long runs of solid-wall valley terraces, Victorian and Edwardian town housing and post-war council estates.
Parts of Mid Glamorgan fall in the higher wind-driven rain exposure bands, especially coastal and upland sites, so render specification, movement joints and detailing at cills, verges and the base of the wall matter more than usual.
For homes in Merthyr Tydfil near busy roads, mineral wool's sound reduction can be a reason to choose it.
- Postcode district
- CF47
- County or area
- Mid Glamorgan
- Nation
- Wales
- Nearby
- Aberdare, Rhondda, Ebbw Vale, Pontypridd
Permissions in Wales
Householder rules in Wales are similar to England's: in Merthyr Tydfil, a similar-looking finish on a house is often permitted, but conservation areas, flats and listed buildings need permission or consent.
In Wales, insulating or re-rendering more than half of a wall's area is treated as renovating a thermal element under Approved Document L (Wales), so building control is involved before work starts.
Wales applies its own external wall fire rules, updated in 2025; on taller residential buildings we specify non-combustible mineral wool systems.
Why choose mineral wool over EPS?
Two reasons come up most: fire and moisture. Mineral wool doesn't burn, which is why guidance for taller residential buildings points to non-combustible external wall materials. It is also vapour-open, so a solid wall that holds some moisture can keep drying outwards through the insulation and render.
The trade-offs are weight and cost. Slabs are denser, need more fixings and take longer to install, so the price per m² is higher than EPS.
Mineral wool external wall insulation prices in Merthyr Tydfil
| Item | Guide price | Notes |
|---|---|---|
| Mineral wool + mineral or silicone render | £125–£170 per m²0% VAT | Excluding scaffold |
| Mineral wool + brick slip | £195–£260 per m²0% VAT | Heavier slip systems need extra fixings |
| Three-bed semi, full house | £11,800–£20,2000% VAT | 80–100 m² of wall, including scaffold |
Confirmed by a fixed written quote after survey. 0% VAT: installing insulation in a home is zero-rated until 31 March 2027, so these figures are the total; 5% applies from 1 April 2027.
From enquiry to finished wall
Tell us about the property
Use the quote tool or form, or call. Photos help.
Free survey
We measure, check the walls and confirm approvals.
Fixed written quote
System, details, access, exclusions and VAT in writing.
Installation
Scheduled for suitable weather, with a clear programme.
Mineral wool EWI in Merthyr Tydfil: questions
Can mineral wool EWI have a brick finish?
Yes. Brick slips can be bonded over mineral wool systems designed for them, with additional fixings for the extra weight.
Is mineral wool better than EPS?
Not always better — different. Mineral wool wins on fire performance, breathability and acoustics; EPS wins on cost, weight and thinner boards for the same U-value. The wall, the building height and your priorities decide it.
Is mineral wool needed for a bungalow?
Rarely for fire reasons. It may still be chosen on a damp-prone solid wall where a vapour-open build-up is wanted.
Do you cover Merthyr Tydfil?
Yes — we survey and quote mineral wool external wall insulation in Merthyr Tydfil (CF47) and nearby Aberdare, Rhondda and Ebbw Vale, with a fixed written price before any work starts.