Opening vents in roof lanterns are usually driven by a chain actuator on a switch, remote or rain sensor. Send photos from Porthmadog (LL49) and we'll tell you which it is — with the price agreed in writing before any work.

What you might be seeing
- Vent stops part-way or makes grinding noises
- Rain sensor doesn't close the vent
- Remote or switch unresponsive
Why it happens
Actuator failure
Chain actuators wear out or jam, especially if they've been forced.
Power or control faults
Transformers, control units, switches and remotes fail; we check these first.
Roof lanterns in Porthmadog
Wind-driven rain is the real test of a roof lantern, and the wetter west sees plenty of it. Leaks that appear only in a storm from one direction usually point to the cappings or eaves on that face — a useful clue when you send us photos.
Coastal wind drives rain hard against lanterns, so cappings and ridge seals on the seaward face take the most punishment.
From Bangor, Gwynedd to Porthmadog is roughly 21 miles — all part of the Gwynedd area we cover.
We also cover nearby Pwllheli (12 miles), Caernarfon (16 miles), Dolgellau (16 miles).
Guide prices for opening vent and actuator repairs in Porthmadog
Guide price for opening vent and actuator repairs: £195–£545 ex VAT (£234–£654 inc VAT), per vent. 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 Wales?
Most lantern repairs in Wales need no approval at all. Where a job turns into a replacement, the Building Regulations 2010 (as applied in Wales) apply and we confirm how the work will be signed off before we start. Listed buildings in Wales need listed building consent from the local planning authority for alterations, with Cadw guidance on historic buildings; check with the council before changing a lantern on a listed property.
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.
Opening vent and actuator repairs in Porthmadog: questions
Do you need to visit to price opening vent and actuator repairs?
Not always. Clear photos are often enough for a guide price. Where the cause isn't obvious, a visit to inspect and water-test is charged from £145 ex VAT, confirmed before we come.
Which places near Porthmadog do you cover?
As well as Porthmadog, we cover nearby Pwllheli, Caernarfon, Dolgellau, Bangor, Gwynedd and the rest of Gwynedd.
Can you add a vent to a lantern that doesn't have one?
Some lanterns can take a replacement vent unit in place of a fixed pane; it depends on the system. We'll check.
Can you add a rain sensor?
Often, if the actuator and control are compatible.
Other lantern repairs in Porthmadog
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Opening vent and actuator repairs near Porthmadog
More about opening vent and actuator repairs · All roof lantern repairs in Porthmadog