Warm Roof Retrofit
The 60-second answer: A warm roof retrofit converts a tired cold-roof flat (typically a 1990s–2000s extension built with insulation between the joists) into a Building-Regs-compliant warm roof — insulation moves above the deck, new membrane goes on top. Cost: £2,400–£4,500 fitted
SIX THINGS, EVERY JOB
What you get with Eco Roofers
What we typically see on Nottinghamshire roofs
Nottinghamshire roof-stock splits roughly into Victorian + Edwardian terrace in central Nottingham (NG1, NG3, NG7), inter-war and post-war semis through Mapperley/Sherwood and the West Bridgford suburbs, ex-coalfield estates around Mansfield (NG18-NG20) and Worksop (S80-S81), plus pantile-and-stone period property in Newark and the Trent-valley villages.
Local weather notes. The county catches Trent-valley weather — fewer high-wind events than the Pennines but more sustained-saturation rainfall in extended wet spells. South-westerly storms strip tile fixings on the same nailing line.
Approved Document L 2022 sets the thermal performance baseline for new roofs (U ≤ 0.16 W/m²K pitched, ≤ 0.18 flat). On flat roofs, BS 6229:2018 sets the design and falls standard. Eco Roofers will guide you through any Building Control notification needed on your job.
Get a free estimate for warm roof retrofit in your area
Enter your postcode and one line about your roof. Sean replies within 24 hours with a written quote.
What will my new roof cost?
Pick your property type and material. Get a typical UK 2026 cost range in seconds — no email required to see the number.
Market-typical UK 2026 ranges. Eco Roofers’ actual quote is built from a free 30-min on-site survey and delivered in writing within 24 hours, including VAT. 25% deposit, balance on satisfactory completion.
When warm roof retrofit is the right answer
If any of these describe your flat roof, retrofit is the answer:
- Cold-roof condensation — black mould on the ceiling, damp staining, peeling paint, especially in winter
- Felt roof at end-of-life — 12+ years old, multiple leaks, mineral coating gone
- Selling within 2-3 years — survey will flag a cold roof; warm-roof retrofit removes the price-down
- Energy bills running high — a poorly-insulated cold roof leaks 25% of a property’s heat (~£200-450/year on a 3-bed semi)
- Building work on the property that triggers Approved Document L (renewing >50% of the roof, or building over an existing flat-roof area)
- Repeat patches not solving the problem — patches address the symptom; retrofit addresses the cause
How a warm roof retrofit works
Most warm-roof retrofits in our 9-town service area are 1–3 day jobs depending on size, with no internal disruption. Here’s the standard sequence:
Day 1 (morning): Scaffolding up. Strip existing membrane down to the deck. Inspect deck condition — if any rot is found, agree the contingency cost in writing before doing extra work.
Day 1 (afternoon): Lay vapour control layer (VCL) sealed continuously across the deck. Tape every penetration.
Day 2 (full day): Lay 100–150 mm rigid PIR insulation board, taped joints. Fit timber upstands to all walls, parapets, and edges. Lay deck-grade OSB or plywood over the insulation if specified by the membrane manufacturer.
Day 3 (full day): Bond the EPDM rubber membrane (or apply GRP fibreglass laminate). Form upstand corners and edge details. Dress drips, parapet flashings, and rooflight kerbs.
Day 3 (final hour): Site clean. Final inspection. Hand over written guarantee.
For larger jobs (40+ m²) the sequence extends to 4–6 days. For smaller jobs (10 m² garage), 1–2 days.
What it costs in Notts and South Yorkshire
Real fitted prices for the sizes we see most often:
| Roof size | Like-for-like felt replacement | Warm roof retrofit + EPDM | Premium for warm retrofit |
|---|---|---|---|
| 10 m² (small extension or garage) | £900–£1,400 | £1,200–£2,400 | £300–£1,000 |
| 20 m² (typical kitchen extension) | £1,500–£2,400 | £2,400–£4,500 | £900–£2,100 |
| 30 m² (large extension) | £2,400–£3,600 | £3,600–£6,500 | £1,200–£2,900 |
| 50 m² (very large or commercial) | £3,500–£5,500 | £6,000–£10,000 | £2,500–£4,500 |
Why retrofit is worth the premium:
- Lifespan triples (15 years felt → 25–40 years EPDM)
- Energy bill saving £200–£450/year (typical 3-bed semi) — pays back in 5–8 years
- Eliminates cold-roof condensation permanently
- Building Regs compliant; no flag at survey
- Avoids the £3,000–£8,000 in eventual internal damage that failing cold roofs cause
Building Regs compliance
Warm roof retrofits trigger Approved Document L 2022 when the area renewed exceeds 50% of the roof. The retrofit must achieve:
- U-value ≤ 0.18 W/m²K for the renewed area (typically 120 mm PIR or thicker)
- Continuous vapour control to prevent moisture migration into the structure
- Notifiable to Building Control via Competent Person Scheme (we handle this)
We design every warm-roof retrofit to British Standard BS 6229 spec — confirmed in writing on every quote. That covers fall ratios, upstand heights, drip projections, and detail compatibility.
Five questions to ask before signing any warm-roof quote
1. What U-value will the finished roof achieve? (Should be 0.13–0.18 W/m²K for warm roof. Anyone who can’t quote a number, walk away.)
2. What’s the membrane manufacturer and warranty? (EPDM should come with at least 20 years from Firestone (Eco Roofers is a Firestone Elevate approved installer).)
3. How will Building Control be notified? (We handle via Competent Person Scheme. Other roofers may charge separately or skip — verify in writing.)
4. What’s the upstand detail at walls and rooflights? (Should be 150mm minimum, with manufacturer-approved cover flashings.)
5. What’s the contingency cap if the deck is rotted underneath? (£300–£600 cap is reasonable. Open chequebook is a red flag.)
What’s included in our warm roof retrofit quote
- Free 30-minute site visit
- Written a clear written estimate by email
- All materials at trade-grade spec (named PIR manufacturer, named EPDM manufacturer)
- Vapour control layer + tape + detail kits
- Pre-formed corner trims and edge profiles
- Building Control notification via Competent Person Scheme
- 10-year installation guarantee + manufacturer’s membrane warranty
- £5M Public Liability cover
- Scaffolding where required (no extra)
25% deposit on booking. Balance on satisfactory completion. VAT-inclusive on domestic.
Where we cover
Warm roof retrofits across Nottinghamshire and South Yorkshire. See our town-specific pages for local pricing and postcode coverage:
- Roofers in Sheffield (S1–S20, S35, S36)
- Roofers in Nottingham (NG1–NG16)
- Roofers in Doncaster (DN1–DN12)
- Roofers in Mansfield (NG18–NG21)
- Roofers in Chesterfield (S40–S45)
- Roofers in Barnsley (S70–S75)
- Roofers in Rotherham (S60–S66)
- Roofers in Worksop (S80–S81)
- Roofers in Newark (NG24, NG23, NG22)
What happens after you call us
No sales pitch, no high-pressure visit. The first 30 minutes is genuinely free — and you get a written quote within 24 hours whether you book or not.
Quick call (5 min)
Tell us what’s wrong, where you are, and roughly when you need it sorted. We’ll book a site visit on the spot.
Same dayOn-site survey (30 min)
Sean comes round, walks the roof, takes photos, and explains exactly what’s wrong and what your options are. No fees, no obligation.
FreeWritten quote (24 hrs)
Fixed-price written quote, VAT-inclusive, with all the materials named. 25% deposit on booking, balance on satisfactory completion.
In writingFAQ
How long does a warm roof retrofit take?
1–3 days for a typical 20m² extension. Larger jobs 4–6 days. We work weather-dependent — won’t bond a roof in active rain or below 5°C deck temperature.
Will I need to move out during the work?
No — warm-roof retrofits are fitted from outside. You can carry on using the rooms below normally. Some dust and noise during the strip; minimal disruption.
Do you need scaffolding?
Usually yes for safety on extensions over 2m high. Scaffolding is included in the fixed-price quote (no extra cost).
What happens if the deck is rotted?
We strip the membrane back, photograph the rot, and agree the contingency cost in writing before doing any extra work. Typical extra: £30–£50 per m² for replacement OSB/plywood. We cap the contingency at £600 in most quotes.
Will my home insurance cover this work?
Insurance won’t pay for planned retrofits. They will sometimes pay for water-damage remediation that traces back to a cold-roof failure, though most policies exclude gradual deterioration. Check your policy.
Can I claim energy-efficiency grants?
ECO4 grants currently fund some flat-roof insulation upgrades for qualifying households (income-eligible or vulnerable households). We can help you check eligibility and refer you to ECO4 installers — we don’t currently process ECO4 ourselves.
Need a warm roof retrofit?
Call Eco Roofers on 07929 379 746 or email sean@eco-roofers.co.uk. Free site visit, a written, fixed-price quote within 24 hours of the site visit, 10-year installation guarantee.
Web form: eco-roofers.co.uk
We design every flat roof to BS 6229 spec — confirmed in writing on every quote. Building Control handled via Competent Person Scheme.
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