We carry out roof lantern resealing in Portishead and across the BS20 area. Resealing is the planned, whole-lantern version of a leak repair: we cut out the old, failed sealant, clean every joint back to a sound surface and reseal the cappings, ridge and eaves with materials that suit the frame.

Is it time for roof lantern resealing?
- Black mould or dirt lines trapped in old silicone
- Sealant applied over sealant from previous patch repairs
- A lantern that is 8–15 years old and has never been maintained
Common causes we find
Sealant past its life
Exposed sealant on a roof takes UV, frost and constant expansion and contraction. It hardens, loses grip and pulls away from the glass.
Wrong product used
General-purpose or acetoxy silicone can fail early on some frames and coatings. Glazing joints need a low-modulus, compatible sealant.
About Portishead and the BS20 area
Western and upland parts of the UK get more rain and more wind-driven rain than the east, and that's what finds weak cappings and blocked eaves first. Lanterns here benefit from a check of the bars on the most exposed face and a clear eaves channel before winter.
Portishead is around 35 miles from Taunton, and both are within our Somerset coverage.
We also cover nearby Nailsea (3 miles), Clevedon (5 miles), Bristol (8 miles).
How much should it cost?
Typical range: £245–£495 ex VAT, which is £294–£594 with VAT, per lantern. Towers or scaffold, where needed, are priced into the quote. Your fixed price is confirmed in writing before any work starts.
Do you need permission in England?
Straightforward repairs — resealing, gaskets, cappings, eaves and like-for-like parts — don't normally need building regulations approval in England. Replacing the whole lantern or enlarging the opening is different and falls under the Building Regulations 2010; we confirm in writing which route applies before any replacement. Listed buildings need listed building consent from the local council for alterations, and conservation areas can have extra controls; like-for-like repairs are treated differently from changes, so check with the council's conservation officer first.
How does it work?
- Send photosWhatsApp or upload a few photos and tell us when it leaks.
- Guide priceWe reply with a guide price and whether a visit is needed.
- Fixed price in writingYou approve the price and the date before anything starts.
- Repair and testWe fix what's failed, water-test where it matters, and send photos.
Roof lantern resealing in Portishead: questions
Do you cover Portishead?
Yes. We cover Portishead, including the BS20 postcode area, as part of Somerset. Send photos by WhatsApp or the form for a free guide price, and we'll confirm the fixed price in writing before any work starts.
Which places near Portishead do you cover?
As well as Portishead, we cover nearby Nailsea, Clevedon, Bristol, Weston-super-Mare and the rest of Somerset.
How much does it cost to reseal a roof lantern?
A standard-size lantern on a single-storey extension is usually £245–£495 ex VAT. Larger lanterns, difficult access or gasket replacement add to that, and you get the fixed price in writing first.
How long does resealing take?
Most domestic lanterns take a few hours in dry weather.
Other lantern repairs in Portishead
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Roof lantern resealing near Portishead
More about roof lantern resealing · All roof lantern repairs in Portishead