What do rooflight upstands & kerbs in Porthmadog involve?
Thinking about rooflight upstands & kerbs in Porthmadog? The short answer: insulated kerbs built and waterproofed to suit your rooflight. The longer answer depends on your roof, which is why we survey before we price.
Chapels, barns and farm buildings converted across Wales often need bespoke or conservation-style glass. In Porthmadog, as anywhere, rooflight upstands & kerbs are the usual choice for new flat-roof openings and rooflight replacements.
From Porthmadog to Pwllheli, Caernarfon and Dolgellau, the same survey-first process applies: measure, specify, fix the price, then fit.
Choices for your Porthmadog project
- Upstand repairs and rebuilds
- Raised upstands for deep green or ballasted roofs
- Internal plaster-box linings
- Upstands to suit single-ply, felt, GRP or liquid roofs
- Proprietary insulated kerbs
- Built square to the rooflight size
- Correct height above the finished roof
Things we check at survey
- Insulation continuity around the upstand affects condensation
- Membrane compatibility with the rooflight's sealants
Planning, building control and Porthmadog
Planning rules in Wales are tighter than in England for rooflights: Class C rights do not apply in conservation areas, National Parks or AONBs, so a rooflight there needs planning permission. A side-facing rooflight within 10.5 m of the boundary must be obscure-glazed, and non-opening unless the opening part is more than 1.7 m above the floor.
Welsh Building Regulations expect new or replacement rooflights to reach 2.2 W/m²K and roof windows 1.4 W/m²K or a Band B rating. Wales also has its own overheating rules (Part O) for new homes, in force since November 2022.
Read the planning permission guide before you commit to a design.
What do rooflight upstands & kerbs cost in Porthmadog?
Prices below are shown including and excluding VAT. In Porthmadog, as elsewhere, making good inside and access equipment are the main variables.
| Option | Guide price inc VAT | Ex VAT |
|---|---|---|
| Large or raised upstand | £715 – £1,195 | £595 – £995 |
| Standard insulated upstand Typical | £475 – £715 | £395 – £595 |
| Small upstand on new roof | £355 – £475 | £295 – £395 |
What happens next
- Send the details. Postcode, rough size and a photo of the roof and room.
- Free site visit. For new installs we survey free, measure and confirm the roof detail.
- Fixed quote. Product, work and price in writing — nothing is ordered until you agree.
- Installation day. Usually one day into a prepared opening, longer for new openings.
Neighbouring towns
More we do in Porthmadog
Common questions
Does every rooflight need an upstand?
Flat and dome rooflights do. Pitched roof windows use flashing kits instead.
What roof coverings do you work with?
Single-ply, EPDM, felt, GRP and liquid-applied systems — or we coordinate with your roofer.
Why is my rooflight cold around the edge?
Usually an uninsulated upstand. Insulating the kerb and lining the reveal fixes most cold spots.
Will I need planning permission in Porthmadog?
Welsh householder permitted development (Class C) allows rooflights that project no more than 15 cm and sit no higher than the existing roof — but not in conservation areas, National Parks, AONBs or World Heritage Sites.
Do I need to be at home for the survey in Porthmadog?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
