The junction where the flat roof covering meets the lantern kerb is a weak point on many extensions. If the membrane is split, unbonded or stopped short, water gets under it and appears inside near the lantern. We re-make the junction in a material that suits your roof.
What are the signs you need flat roof junction and flashing repairs?
- Leak near the lantern but not from the frame
- Splits, blisters or lifted edges in the roof covering by the kerb
- Missing or loose edge trims and flashings
- Ponding on the roof next to the lantern
What usually causes it?
Unbonded membrane
EPDM or single-ply that has come away from the kerb lets water run behind it.
Cracked GRP
Fibreglass roofs can crack at the kerb corner where movement concentrates.
Missing trims
Without a trim or flashing to protect the top edge, water gets in behind the membrane.
How do we fix it?
- Identify the roof systemWe confirm whether it's EPDM, GRP, felt or single-ply and how it's been detailed.
- Cut back and re-makeFailed material is cut back to sound and the junction re-made with compatible products.
- Trim and testTrims or flashings are fitted and the area water-tested.
Is it the flat roof or the lantern that's leaking?
Often it's hard to tell from inside. Water can travel along the deck before it shows. Our guide flat roof or lantern leak? explains the clues; on site we test the lantern and the roof separately so you only pay to fix what's failed.
What should you expect to pay for flat roof junction and flashing repairs?
Guide prices assume a standard lantern on a single-storey roof with safe ladder access. Where a tower or scaffold is needed we add it to the quote (typically £245–£895 ex VAT). Diagnostic visits start from £145 ex VAT. Your fixed price is confirmed in writing before any work starts. See all guide prices.
Where is this on the lantern?
Highlighted in amber: flat roof junction.
Questions about flat roof junction and flashing repairs
Do you repair the whole flat roof?
We repair the area around the lantern. If the wider roof is failing we'll tell you and can quote, but we won't push a new roof if a local repair will do.
What does a junction repair cost?
Usually £245–£695 ex VAT, confirmed in writing before work starts.
Can you repair a GRP roof without it showing?
Repairs are colour-matched as closely as possible, but new topcoat next to weathered topcoat can look slightly different at first.
Where do we carry out flat roof junction and flashing repairs?
We cover the whole of the UK. Choose your area for local details and towns we cover.
England
- Bedfordshire
- Berkshire
- Bristol
- Buckinghamshire
- Cambridgeshire
- Cheshire
- Cornwall
- Cumbria
- Derbyshire
- Devon
- Dorset
- County Durham
- East Riding of Yorkshire
- East Sussex
- Essex
- Gloucestershire
- Greater London
- Greater Manchester
- Hampshire
- Herefordshire
- Hertfordshire
- Isle of Wight
- Kent
- Lancashire
- Leicestershire
- Lincolnshire
- Merseyside
- Norfolk
- North Yorkshire
- Northamptonshire
- Northumberland
- Nottinghamshire
- Oxfordshire
- Rutland
- Shropshire
- Somerset
- South Yorkshire
- Staffordshire
- Suffolk
- Surrey
- Tyne and Wear
- Warwickshire
- West Midlands
- West Sussex
- West Yorkshire
- Wiltshire
- Worcestershire
Wales
Scotland
- Aberdeen and Aberdeenshire
- Highlands and Islands
- Moray
- Dundee and Angus
- Perth and Kinross
- Fife
- Edinburgh and the Lothians
- Glasgow and Clyde
- Lanarkshire
- Ayrshire
- Stirling and Falkirk
- Dumfries and Galloway
- Scottish Borders
- Argyll and Bute
