Friern Barnet guide prices
Small sealed unit
Misted or cracked unit up to about 1 m² measured, made and refitted
Medium sealed unit
Units up to about 2 m², or toughened and laminated
Large or specialist
Triple glazed, solar-control or heavy units needing lifting gear
Guide ranges. The first visit is charged and priced before booking; any new glass is priced in writing before work starts. Scaffold, access towers or a crane are priced separately if the job needs them, and building control fees, where a job needs them, are shown as their own line.
Fitting across Friern Barnet and nearby
Covering Friern Barnet means covering the people who live and work there, not a single postcode. We take on domestic and commercial jobs in N12, N11 and N20, and are happy to quote further out in Muswell Hill and Finchley. If your address sits between towns, tell us and we will confirm whether it falls in our normal area or needs travel set out separately on the quote.
On the day, we cover
- Old glass taken out safely and removed from site
- New glazing tapes, gaskets or sealant fitted to suit the frame
- Joints water tested and the glass cleaned inside and out
- Condensation or a failed seal — We confirm whether the mist is inside the sealed unit or on the room-side surface.
- Can the glass come out? — We check whether your rooflight has removable glass or a bonded unit before booking a fitting visit.
How the glass is replaced
On the fitting visit, the room below is protected first. The beads or cappings come off, the old unit is lifted out with suction lifters, and the rebate is cleaned and checked for damage or blocked drainage. The new sealed unit goes in on fresh packers and gaskets, the cappings are refitted and sealed, and the glass is cleaned. Most glass swaps take half a day once the new glass is made.
Planning and building rules in England
In England, a new rooflight opening generally needs building regulations approval because the roof structure is altered and the glazing must meet energy rules: 2.2 W/m²K for a rooflight in an existing home, or 1.4 W/m²K (or WER Band B) for a roof window. Planning is often not needed on a house: permitted development covers rooflights that stand no more than 0.15 m proud of the roof slope and sit below the highest part of the roof. Flats, listed buildings and areas with an Article 4 direction are different, so we check your address first.
What to send us
Photos of the problem glass from inside and out, a rough width and length, and whether the rooflight opens or is fixed are enough to price the first visit. Add the postcode and how the roof is reached, and tell us if more than one unit has misted.
Common questions in Friern Barnet
Can I upgrade the glass while it is being replaced?
Usually. Solar-control, self-cleaning, toughened or laminated glass can be specified as long as the frame can take the thickness and weight. We check that on the measuring visit and price the options side by side.
How long does new rooflight glass take?
The new sealed unit is made to the measured size, so there is a gap between the measuring visit and the fitting visit while it is produced. We give you the expected timing when we price the glass, and book the fitting once it has arrived.
Is new glass or a new rooflight better value?
If the frame, gaskets and drainage are sound, new glass is usually the cheaper fix. If the frame is cracked, distorted or leaking at the kerb, a full replacement is better value. After the measuring visit we price both so you can compare.
Got a leak or a misted unit in Friern Barnet? Send photos first and we will tell you what the visit costs before booking.

