- Guide price
- £2,750–£4,800
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Merthyr Tydfil at a glance
- Largest towns
- Merthyr Tydfil, Treharris
- Postcode areas
- CF
- Building control
- Merthyr Tydfil County Borough Council
- Neighbouring areas
- Rhondda Cynon Taf · Blaenau Gwent · Caerphilly · Torfaen
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a rooflight upstand cost in Merthyr Tydfil?
Guide prices including VAT at Wales rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £2,750–£4,800 |
| Extension (20 m²), EPDM, new deck + insulation | £2,600–£4,500 |
| Extension (20 m²), EPDM with sedum green roof | £4,050–£7,450 |
Which flat roofs are common in Merthyr Tydfil?
Flat roofs in Merthyr Tydfil sit on newer estates where the first extension roofs are now being replaced, terraced streets with flat-roofed rear kitchens and bathrooms and 1930s semis with flat-roofed garages and kitchen extensions. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in Wales
Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Merthyr Tydfil the application goes to Merthyr Tydfil County Borough Council. More on the rules.
Should I choose a fixed or an opening rooflight, or a lantern?
Choose a fixed rooflight if you only want daylight, an opening one if the room needs ventilation, and a lantern if you want a raised, pitched glazed feature over a larger space.
- Fixed flat rooflights are the simplest and usually the cheapest option. They have the fewest moving seals, and the upstand detail is straightforward.
- Opening rooflights can be manual or electric, and electric units often include a rain sensor that closes them automatically. They need a power supply planned in before the ceiling is finished. Some are designed as hatches to give access to the roof.
- Roof lanterns have a framed, pitched glazed top that brings in more light and adds height to the room. They are heavier and larger, so the upstand has to be strong, level and square, and the joists around the opening may need strengthening.
Whatever you choose, it helps to settle on the unit before the roof is built, so the upstand can be made to the maker's sizes. If you've already chosen one, we build the upstand to suit it.
How long does a rooflight upstand last?
A properly built, insulated upstand with waterproofing dressed to the maker's details should last as long as the roof covering around it. The rooflight's own seals and opening parts may need attention sooner.
Upstands fail early when they are too low, poorly insulated or built on a deck that moves. Keeping the area around the rooflight clear of leaves and debris, checking the corners after storms from a safe position and cleaning the glazing gently all help. Never lean on or stand on a rooflight: most are fragile, and the roof around them should be treated as fragile too. The maintenance guide covers routine checks.
Which towns in Merthyr Tydfil do we cover?
Rooflights in flat roofs in Merthyr Tydfil: questions
Which towns in Merthyr Tydfil do you cover?
All of Merthyr Tydfil. 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 rooflight upstand cost in Merthyr Tydfil?
£2,750–£4,800 for a 20 m² insulated EPDM extension roof with one rooflight upstand, at Wales guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Merthyr Tydfil?
All of Merthyr Tydfil, including the CF postcode areas. Send your full postcode and we'll confirm.
Will an opening rooflight let rain in if I leave it open?
Many electric opening rooflights include a rain sensor that closes them automatically when it starts raining. With manual units, it's up to you to close them.
Why does my rooflight drip in winter?
If it only drips in cold weather and not when it rains, it is probably condensation on a cold, poorly insulated upstand or older glazing. Better ventilation helps, and an insulated kerb and modern unit usually fix it.
How high should a flat rooflight upstand be?
Usually at least 150 mm from the finished roof surface to the top of the waterproofing, so the joint stays above standing water. Some rooflight makers specify more.
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