What the job costs in Blackheath
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 Blackheath and nearby
Fitters travel to the job, so the address is what counts. In Blackheath that means postcode districts SE3, SE13 and SE10, and the same teams can just as easily take on work in Lewisham, about 1 mile away, or Greenwich at roughly 1 mile. Survey and fitting dates are offered according to fitter availability, and travel is built into the quote rather than added later.
What the job includes
- Frame rebate cleaned and checked for damage, corrosion or failed seals
- Old glass taken out safely and removed from site
- Measuring visit to size the glass and identify its make-up
- Condition of the frame — We look at the frame closely before committing to new glass.
- Condensation or a failed seal — We confirm whether the mist is inside the sealed unit or on the room-side surface.
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.
Regulations for Blackheath properties
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
To price the measuring visit, send a photo of the rooflight from inside showing the misting or crack, one from outside if you can reach a safe viewpoint, and the rough size of the glass. If you know the make or have the original paperwork, include that too, along with the postcode.
Common questions in Blackheath
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.
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.
Can you replace just the glass in my rooflight?
Often, yes. If the frame, gaskets and drainage are sound, a new sealed unit can go into the existing frame. If the frame has failed, is distorted or leaks around the edge, replacing the whole rooflight is usually the better answer, and we tell you that.
Got a leak or a misted unit in Blackheath? Send photos first and we will tell you what the visit costs before booking.

