Melksham at a glance
- Postcode districts
- SN12
- Population
- about 19,357 (GeoNames)
- Council area
- Wiltshire Council
- Building approval
- Wiltshire Council building control, or a registered building control approver
- Nearest main town
- Bath, about 10 miles
- Guide price region
- South West (+3% on West Midlands rates)
What makes a good extension roof in Melksham?
Ponding against the house wall is a common reason for replacing an extension roof in Melksham. When the deck dips near the wall or the fall runs the wrong way, water sits against the abutment and eventually gets in. A new roof with corrected falls moves the water to the gutter.
In a town like Melksham, flat roofs are commonly found on bungalows with flat-roofed side extensions and dormers or lock-up garage blocks on estates. The South West averages roughly 1,260 mm of rain a year and many roofs face wind off the Atlantic, so we specify fixings and edge details for wind uplift as well as drainage.
How much does a new extension roof cost in Melksham?
Guide price in Melksham: £2,900–£5,050 for a 20 m² extension roof in EPDM with a new deck and insulation, including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM, new deck + insulation | £2,900–£5,050 |
| Extension (20 m²), GRP, new deck + insulation | £3,100–£5,550 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £3,100–£5,400 |
| Single garage (18 m²), EPDM rubber | £1,650–£2,900 |
Why does water pond or leak where the extension meets the house?
Usually because the fall runs the wrong way, the abutment detail has failed, or the roof has sagged close to the wall. The junction with the house is the most common leak point on an extension roof.
If the roof falls towards the house, or the deck dips near the wall, water sits against the upstand and finds any weakness in the flashing above. Older roofs often have the felt simply turned up the brickwork with no cover flashing, or a flashing that has pulled out of its joint. A patch will not change a fall. We re-firr or use tapered insulation so water runs away from the wall, then form a new upstand, usually 150 mm above the finished roof, with a flashing chased into the mortar joint.
Rooflights and lanterns are the other weak point. A lantern needs a properly built kerb with the membrane dressed up and under its frame. We rebuild rooflight upstands within the roof job; we do not supply the lantern itself. Our guide to ponding water explains the causes in more depth.
What's included?
- Free survey of the roof, abutment and room below
- Falls set away from the house wall
- New deck, vapour control layer and warm-roof insulation
- Staged strip-out so the room stays weathertight
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
Extension and kitchen roofs in Melksham: questions
Do you cover Melksham?
Yes. Melksham is part of our Wiltshire coverage, including postcode districts SN12. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Melksham?
Where the work needs approval it goes to Wiltshire Council building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a new extension roof cost in Melksham?
£2,900–£5,050 for a 20 m² extension roof in EPDM with a new deck and insulation, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Do I need my neighbour's permission to replace an extension roof?
Not for a like-for-like re-cover in most cases. The Party Wall Act in England and Wales can apply if the work raises or cuts into a shared wall, so we flag that at survey.
How do I know my extension roof needs replacing rather than repairing?
Repeated leaks, a soft deck, wet insulation or widespread cracking point to replacement. A single defect on a dry, sound roof can usually be repaired.