Keynsham at a glance
- Postcode districts
- BS31
- Population
- about 19,603 (GeoNames)
- Council area
- Bath & North East Somerset Council
- Building approval
- Bath & North East Somerset Council building control, or a registered building control approver
- Nearest main town
- Bristol, about 5 miles
- Guide price region
- South West (+3% on West Midlands rates)
What does a balcony or terrace in Keynsham need?
Owners of flats in Keynsham sometimes find that a neighbour's balcony is leaking into their home. Where a balcony serves one flat but sits over another, the repair needs proper waterproofing and drainage, and a clear written specification helps everyone involved agree the work.
In a town like Keynsham, flat roofs are commonly found on lock-up garage blocks on estates or terraced streets with flat-roofed rear kitchens and bathrooms. 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 balcony or terrace waterproofing cost in Keynsham?
At South West guide rates, a 12 m² balcony in a liquid-applied system including scaffold comes to £1,950–£3,350 including VAT. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Balcony (12 m²), liquid-applied, scaffold | £1,950–£3,350 |
| Single garage (18 m²), EPDM rubber | £1,650–£2,900 |
| Extension (20 m²), GRP, new deck + insulation | £3,100–£5,550 |
Which waterproofing system is best for a balcony?
For most small balconies, a liquid-applied membrane is the practical choice, because it is brushed or rolled on and forms one continuous layer around posts, door frames and outlets with no seams to fail. Many systems include a hard-wearing, anti-slip topcoat.
GRP fibreglass gives a rigid, walkable surface and suits balconies left exposed rather than paved. On larger roof terraces under paving or decking, single-ply membranes are common, and mastic asphalt has a long record on concrete terraces and blocks of flats.
The choice also depends on what goes on top. Paving on pedestals protects the membrane, while an exposed balcony needs a system rated for foot traffic in its own right. We specify the build-up at survey.
What's included?
- Sealed details at doors, outlets, walls and balustrade posts
- Strip-out of the failed membrane and deck repairs
- Free survey of the deck, falls, outlets and door thresholds
- Lifting and setting aside of existing paving or decking
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?
Balconies and roof terraces in Keynsham: questions
Do you cover Keynsham?
Yes. Keynsham is part of our Somerset coverage, including postcode districts BS31. 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 Keynsham?
Where the work needs approval it goes to Bath & North East Somerset 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 balcony or terrace waterproofing cost in Keynsham?
£1,950–£3,350 for a 12 m² balcony in a liquid-applied system including scaffold, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
What is an inverted roof terrace?
It is a terrace where the insulation sits above the waterproofing, held down by paving or ballast. The membrane stays protected and at a steadier temperature.
Can I put decking straight onto my flat roof?
Not directly onto the membrane. Decking needs a supporting system that spreads the load and lets water drain, and the roof must be checked for the extra weight.