- Guide price
- £1,750–£3,000
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Torfaen at a glance
- Largest towns
- Cwmbran, Pontypool
- Postcode areas
- NP
- Building control
- Torfaen County Borough Council
- Neighbouring areas
- Newport · Caerphilly · Blaenau Gwent · Monmouthshire
- Guide price region
- Wales (−8% on West Midlands rates)
How much does balcony or terrace waterproofing cost in Torfaen?
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 |
|---|---|
| Balcony (12 m²), liquid-applied, scaffold | £1,750–£3,000 |
| Single garage (18 m²), EPDM rubber | £1,450–£2,600 |
| Extension (20 m²), GRP, new deck + insulation | £2,750–£4,950 |
Which flat roofs are common in Torfaen?
Flat roofs in Torfaen sit on newer estates where the first extension roofs are now being replaced, bungalows with flat-roofed side extensions and dormers and terraced streets with flat-roofed rear kitchens and bathrooms. 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 Torfaen the application goes to Torfaen County Borough Council. More on the rules.
How long does it take to waterproof a balcony?
A small balcony is typically waterproofed in two to four working days, plus time for scaffold if it is above ground floor. Liquid and GRP systems need dry weather and cure time between coats, which sets the pace.
The balcony door will be out of use while the membrane is laid and curing, and the room behind may be noisy while old paving or screed is broken out. If the team needs to work through the house, we agree a route and protect floors. Larger terraces with paving or decking take longer, because the finish has to be lifted and reinstated. Resin systems smell while they cure, so nearby windows are best kept closed.
Do I need planning permission for a balcony or roof terrace?
For a new balcony or roof terrace, generally yes. In England, balconies and raised platforms are not permitted development for houses, so a planning application is normally needed, and the other nations have their own rules.
Re-waterproofing an existing, approved balcony that looks the same afterwards does not normally need planning. Building regulations are a separate question. A terrace over a heated room is a thermal element, so replacing most of it can bring insulation requirements and approval. Turning a flat roof into a terrace also raises structural questions, because people, furniture and paving add load, and it needs guarding, such as a balustrade, that meets the regulations. A structural engineer should confirm that the roof can carry the new use.
Listed buildings and conservation areas add another layer of control. Our building regulations page covers approvals, and our planning permission guide covers the planning side.
Which towns in Torfaen do we cover?
Balconies and roof terraces in Torfaen: questions
Which towns in Torfaen do you cover?
All of Torfaen. 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 balcony or terrace waterproofing cost in Torfaen?
£1,750–£3,000 for a 12 m² balcony in a liquid-applied system including scaffold, 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 Torfaen?
All of Torfaen, including the NP postcode areas. Send your full postcode and we'll confirm.
Is a roof terrace heavier than a normal flat roof?
Yes. Paving, people, planters and furniture all add load, so a structural engineer should confirm the roof can carry it before a terrace is formed.
Why is water coming through the ceiling below my balcony?
The usual causes are a failed door threshold, a blocked or poorly sealed outlet, or a fixing through the membrane. A survey, sometimes lifting paving, finds the source.
How long does balcony waterproofing last?
It depends on the system and how well it is protected. As indicative ranges, liquid-applied systems last 10–25+ years by product and mastic asphalt 30–60, with good maintenance.
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