Stevenage at a glance
- Postcode districts
- SG1, SG2
- Population
- about 91,774 (GeoNames)
- Council area
- Stevenage Borough Council
- Building approval
- Stevenage Borough Council building control, or a registered building control approver
- Nearest main town
- Luton, about 9 miles
- Guide price region
- East of England (+5% on West Midlands rates)
What does a balcony or terrace in Stevenage need?
Door thresholds are a common reason for balcony work in Stevenage. Where a door was fitted with a low step-out and no drainage channel, water driven against the frame finds its way under the sill. Re-waterproofing gives the chance to rebuild that detail properly.
Stevenage's flat roofs are mostly on terraced streets with flat-roofed rear kitchens and bathrooms, with plenty on 1960s and 1970s link-detached houses with flat-roofed garages and porches too. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof.
How much does balcony or terrace waterproofing cost in Stevenage?
Guide price in Stevenage: £2,000–£3,400 for a 12 m² balcony in a liquid-applied system including scaffold, including VAT at East of England 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 | £2,000–£3,400 |
| Single garage (18 m²), EPDM rubber | £1,700–£2,950 |
| Extension (20 m²), GRP, new deck + insulation | £3,150–£5,650 |
How are thresholds, drainage and paving handled on a terrace?
They are designed together, because most balcony leaks start at the door threshold, a blocked outlet or a fixing driven through the membrane. Getting those three right matters more than the brand of membrane.
Thresholds: upstands are usually 150 mm above the finished surface, but a level or low step-out door cannot always achieve that. Where the upstand has to be reduced, extra protection is needed, such as a drainage channel at the door and a fall away from it, and the membrane must still run up and under the door sill.
Drainage: every terrace needs a reliable way off for water, with outlets sized for the area and an overflow if one outlet could block. Outlets under paving need access for cleaning.
Inverted roofs and pedestals: on an inverted roof the insulation sits above the waterproofing and is held down by paving or ballast, protecting the membrane from sun and foot traffic. Adjustable pedestals lift paving slabs level above the falls, so water drains underneath and the surface stays flat. Balustrade posts are fixed through upstands or side-fixed where possible, with every penetration sealed into the membrane.
What's included?
- Free survey of the deck, falls, outlets and door thresholds
- New liquid, GRP, single-ply or asphalt waterproofing
- Sealed details at doors, outlets, walls and balustrade posts
- Strip-out of the failed membrane and deck repairs
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?
- Hitchin · 5 mi
- Letchworth Garden City · 5 mi
- Welwyn Garden City · 7 mi
- Harpenden · 9 mi
- Hertford · 9 mi
- Luton · 9 mi
Balconies and roof terraces in Stevenage: questions
Do you cover Stevenage?
Yes. Stevenage is part of our Hertfordshire coverage, including postcode districts SG1, SG2. 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 Stevenage?
Where the work needs approval it goes to Stevenage 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 balcony or terrace waterproofing cost in Stevenage?
£2,000–£3,400 for a 12 m² balcony in a liquid-applied system including scaffold, at East of England 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.