Portsmouth at a glance
- Postcode districts
- PO1, PO2, PO3, PO4, PO5, PO6
- Population
- about 208,100 (GeoNames)
- Council area
- Portsmouth City Council
- Building approval
- Portsmouth City Council building control, or a registered building control approver
- Nearest main town
- Southampton, about 15 miles
- Guide price region
- South East (+10% on West Midlands rates)
What does a balcony or terrace in Portsmouth need?
Owners of flats in Portsmouth 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 city like Portsmouth, flat roofs are commonly found on shops with flat-roofed rear stores below flats or 1930s semis with flat-roofed garages and kitchen extensions. Much of the South East sits in the drier Thames catchment at roughly 730 mm of rain a year, so the usual failures are at joints, upstands and outlets rather than from sheer volume of rain.
How much does balcony or terrace waterproofing cost in Portsmouth?
Guide price in Portsmouth: £2,100–£3,600 for a 12 m² balcony in a liquid-applied system including scaffold, including VAT at South East 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 | £2,100–£3,600 |
| Single garage (18 m²), EPDM rubber | £1,750–£3,100 |
| Extension (20 m²), GRP, new deck + insulation | £3,300–£5,900 |
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.
What's included?
- Written workmanship guarantee, with approvals handled where needed
- Free survey of the deck, falls, outlets and door thresholds
- Lifting and setting aside of existing paving or decking
- New liquid, GRP, single-ply or asphalt waterproofing
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 Portsmouth: questions
Do you cover Portsmouth?
Yes. Portsmouth is part of our Hampshire coverage, including postcode districts PO1, PO2, PO3, PO4, PO5, PO6. 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 Portsmouth?
Where the work needs approval it goes to Portsmouth City 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 Portsmouth?
£2,100–£3,600 for a 12 m² balcony in a liquid-applied system including scaffold, at South East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
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.
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.