What the job costs in Barnet
Pair of windows
Two roof windows into a loft room, flashings and linings
Three or four windows
Bigger loft rooms or stairwells
Balcony or combination
Balcony-style or stacked window combinations
Guide ranges for supply & fit. Your price is fixed in a written quote after we have seen photos or surveyed. 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.
Areas around Barnet we cover
Our fitters come to you. For Barnet that covers EN5, EN4 and N20, plus nearby East Barnet and Friern Barnet. We do not keep a yard or showroom in the area, and you do not need to visit one. The survey happens at your property or, for fit-only work, from the photos you send. Dates follow fitter availability, which we confirm when you accept the quote.
Already bought your unit?
Supply and fit tends to suit people who would rather not pick a unit from a catalogue. We look at the roof, the opening and how you use the room, then put a loft roof window on the quote that fits all three. Fit-only suits people who already know what they want, or have one on site. We are happy with either. The difference is who stands behind what: on fit-only, the maker or retailer covers the product, and our workmanship guarantee covers the installation.
Included in the work
- Insulation collars fitted so the room's insulation meets each frame
- Window positions set out on the slope to line up inside and out
- Underlay dressed and taped around every frame
- Balcony-style windows — We check the rafters and the roof pitch before recommending balcony-style windows.
- Energy performance in a loft — We check every window meets the energy limit for roof windows in existing homes.
Fitting your loft roof window, step by step
On the day, you need to be in at the start and at the end. In between, the fitters get on with it. They will want the room below cleared where possible, a parking spot if you have one, and somewhere to set the unit down safely. After checking the opening and the upstand or flashing, they fix a loft roof window, seal it and finish the inside. Packaging and any old unit leave with them unless the quote says otherwise.
Regulations for Barnet properties
Replacing a rooflight in an English home is a controlled fitting: it has to be self-certified by a scheme-registered installer or notified to building control. We are not registered with a competent person scheme, so replacements we fit are notified with a building notice, and the new unit has to meet current energy limits. Adding a new one usually means a building regulations application, because joists or rafters are trimmed. On the planning side, most house rooflights are permitted development if they project 0.15 m or less; on a side slope the glass must be obscured and fixed unless the opening part is over 1.7 m above the floor.
Details that speed up your quote
A fast quote needs five things: a photo of the roof from outside, one from the room below, rough sizes of the opening or the space, the roof covering (felt, single-ply, fibreglass, tiles, slate or metal), and a note on access. If you have already bought the unit, add the product link or spec sheet. And give us the postcode, EN5 or a neighbouring district.
Common questions in Barnet
Will my new loft roof window leak?
A correctly fitted unit should not. Leaks usually trace back to the detail around the frame: an upstand that is too low, a membrane or flashing that is not dressed properly, sealant applied to a damp surface, or water ponding against the kerb. We fit to the maker's instructions and check each of those points. The fitting carries a written workmanship guarantee, with its terms set out on your quote.
What if my roof opening is the wrong size for the loft roof window?
We find out before the fitting day, not on it. If the opening is slightly out, it can usually be adjusted by trimming or by packing out the upstand. If it is a long way off, the choice is between altering the opening and changing the unit. Bear in mind that rooflights are often sold by builder's opening size rather than external size, so check which one your measurement refers to.
Does a rooflight need building regulations approval?
A new opening usually needs building regulations approval. A replacement is a controlled fitting: it must be self-certified by an installer registered with a competent person scheme or notified to building control. We are not registered with a scheme, so replacements we fit are notified to building control with a building notice, and the council's fee is shown on your quote.
Questions before you commit? Send them over with your Barnet postcode and we will answer them plainly, with a quote alongside.

