- Guide price
- £800–£1,300
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Hertfordshire at a glance
- Largest towns
- Watford, Hemel Hempstead, Stevenage, St Albans
- Postcode areas
- AL, CM, EN, HP, SG, WD
- Building control
- Watford Borough Council, Dacorum Borough Council, Stevenage Borough Council and 7 other councils
- Neighbouring areas
- Bedfordshire · Buckinghamshire · London · Surrey
- Guide price region
- East of England (+5% on West Midlands rates)
How much does a porch or bay roof cost in Hertfordshire?
Guide prices including VAT at East of England rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Porch or bay (4 m²), EPDM | £800–£1,300 |
| Single garage (18 m²), EPDM rubber | £1,700–£2,950 |
| Extension (20 m²), GRP, new deck + insulation | £3,150–£5,650 |
Which flat roofs are common in Hertfordshire?
Flat roofs in Hertfordshire sit on low-rise post-war blocks of flats, 1960s and 1970s link-detached houses with flat-roofed garages and porches and bungalows with flat-roofed side extensions and dormers. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Hertfordshire the application goes to Watford Borough Council, Dacorum Borough Council, Stevenage Borough Council and 7 other councils. More on the rules.
Which material looks best on a porch or bay roof?
For most porches, EPDM rubber gives a neat, dark grey finish that sits quietly on the front of a house, and on a small roof it can usually be laid as one piece. For angled bays and curved canopies, GRP fibreglass or a liquid-applied system follows the shape without folds or joins.
Many older bay windows and porches were finished in lead, which has a distinctive look. Where you want to keep that appearance, especially on a period house, we can discuss a lead-look finish or retaining lead flashings at the wall. On a listed building or in a conservation area, changing from lead to a membrane may need consent, so we check that at survey.
Colour matters more here than on a hidden rear roof. GRP topcoats come in several colours, and EPDM is typically black or dark grey.
How long does a porch roof replacement take?
Most porch and bay roofs are replaced in a single day, weather permitting. GRP or liquid systems may need a return visit for a topcoat once the first coat has cured.
Disruption is minimal. You may need to use another door while a front porch is being re-roofed, and the area below should be kept clear for safety. A ground-floor bay can usually be reached from a tower or platform steps, while a first-floor bay may need a small scaffold. The window below stays usable, though it is best kept closed while resin is curing.
Which towns in Hertfordshire do we cover?
- Watford
- Hemel Hempstead
- Stevenage
- St Albans
- Welwyn Garden City
- Cheshunt
- Hatfield
- Bishop's Stortford
- Borehamwood
- Hitchin
- Hoddesdon
- Letchworth Garden City
- Harpenden
- Bushey
- Hertford
- Rickmansworth
- Potters Bar
- Berkhamsted
- Ware
- Royston
Porch, bay and canopy roofs in Hertfordshire: questions
Which towns in Hertfordshire do you cover?
All of Hertfordshire. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a porch or bay roof cost in Hertfordshire?
£800–£1,300 for a small 4 m² porch or bay roof in EPDM, at East of England guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Hertfordshire?
It depends on where the roof is: in Hertfordshire that's Watford Borough Council, Dacorum Borough Council, Stevenage Borough Council and 7 other councils. Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. We confirm which applies at the survey.
Why is my porch roof leaking when the felt looks fine?
The water is often coming from the wall junction, not the roof surface. A failed flashing, cracked mortar or porous brick above can let water in behind the upstand.
Should I replace lead on my bay roof with EPDM or GRP?
It depends on the house and your priorities. Membranes usually cost less and have no scrap value to thieves, but on a period or listed property keeping a lead appearance may matter or be required.
Can a canopy over a front door be re-covered?
Yes. Small canopies are re-covered in the same way as porches, usually in EPDM or GRP, subject to the minimum charge.
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