Penarth at a glance
- Postcode districts
- CF64
- Population
- about 23,437 (GeoNames)
- Council area
- Vale of Glamorgan Council
- Building approval
- Vale of Glamorgan Council building control, or a registered building control approver
- Nearest main town
- Cardiff, about 3 miles
- Guide price region
- Wales (−8% on West Midlands rates)
What does a balcony or terrace in Penarth need?
Settled, rocking or cracked paving is a common reason to re-waterproof a terrace in Penarth. Slabs bedded directly on the membrane can damage it over time. Relaying them on adjustable pedestals protects the waterproofing and gives a level surface that drains underneath.
Around Penarth, flat roofs are common on low-rise post-war blocks of flats and on 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.
How much does balcony or terrace waterproofing cost in Penarth?
For Penarth we use Wales rates: £1,750–£3,000 is the guide for a 12 m² balcony in a liquid-applied system including scaffold, VAT included. 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 |
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
- Lifting and setting aside of existing paving or decking
- Strip-out of the failed membrane and deck repairs
Building regulations in Wales
The Welsh Approved Document L applies. Renovating more than half of a roof over a heated room means upgrading it to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K. Welsh Government guidance is that most re-roofing needs building control approval, so check whenever more than a quarter of a roof is replaced or repaired. We deal with the application as part of the job. More on the rules.
Which nearby areas do we also cover?
Balconies and roof terraces in Penarth: questions
Do you cover Penarth?
Yes. Penarth is part of our Vale of Glamorgan coverage, including postcode districts CF64. 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 Penarth?
Where the work needs approval it goes to Vale of Glamorgan 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 Penarth?
£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.
Can you waterproof a balcony without lifting the tiles?
Sometimes a liquid system can go over a sound, well-bonded surface, but if water is already getting under the tiles they usually have to come up.
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.