Stockton-on-Tees at a glance
- Postcode districts
- TS15, TS16, TS17, TS18, TS19, TS20, TS22, TS23
- Population
- about 79,957 (GeoNames)
- Council area
- Stockton-on-Tees Borough Council
- Building approval
- Stockton-on-Tees Borough Council building control, or a registered building control approver
- Nearest main town
- Middlesbrough, about 3 miles
- Guide price region
- North East (−7% on West Midlands rates)
What makes a good extension roof in Stockton-on-Tees?
Extension roofs in Stockton-on-Tees are often replaced because the original was built cheaply: thin chipboard decks, little or no insulation and felt turned up the wall without a proper flashing. Twenty or thirty years on, those weaknesses show up as leaks at the back wall and a cold, damp ceiling.
Stockton-on-Tees's flat roofs are mostly on 1930s semis with flat-roofed garages and kitchen extensions, with plenty on newer estates where the first extension roofs are now being replaced too. England averages roughly 870 mm of rain a year; the North East is drier than the west but cold and windy near the coast, so wind uplift and freeze-thaw are in the specification.
How much does a new extension roof cost in Stockton-on-Tees?
At North East guide rates, a 20 m² extension roof in EPDM with a new deck and insulation comes to £2,600–£4,550 including VAT. 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 | £2,600–£4,550 |
| Extension (20 m²), GRP, new deck + insulation | £2,800–£5,000 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £2,800–£4,850 |
| Single garage (18 m²), EPDM rubber | £1,500–£2,600 |
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
- New abutment upstand and flashing, plus rebuilt rooflight kerbs
- New deck, vapour control layer and warm-roof insulation
- Falls set away from the house wall
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?
- Billingham · 2 mi
- Thornaby-on-Tees · 3 mi
- Middlesbrough · 3 mi
- Yarm · 5 mi
- Hartlepool · 9 mi
- Darlington · 10 mi
Extension and kitchen roofs in Stockton-on-Tees: questions
Do you cover Stockton-on-Tees?
Yes. Stockton-on-Tees is part of our County Durham coverage, including postcode districts TS15, TS16, TS17, TS18, TS19, TS20 and 2 more. 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 Stockton-on-Tees?
Where the work needs approval it goes to Stockton-on-Tees Borough 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 Stockton-on-Tees?
£2,600–£4,550 for a 20 m² extension roof in EPDM with a new deck and insulation, at North East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Can you keep my existing roof lantern?
Often, if the lantern itself is sound. We lift it, rebuild the kerb, dress the new membrane up the upstand and refit the lantern.
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.