Fit-onlySupply & fitReplacementsTrade fitting
Fitting teams across England, Wales, Scotland & NI · Call 0800 088 6248
RooflightInstallers.co.uk
Lisburn · BT27 · County Antrim

Loft conversion roof windows in Lisburn

If the loft roof window on your roof now is misted, discoloured, cracked or letting water in, replacing it is often simpler than people expect. The old unit comes out, we inspect the kerb or frame underneath, and we decide with you whether it can be reused or needs rebuilding. Then the new one goes in, sealed to the roof covering and finished inside. We handle this kind of loft conversion roof windows in Lisburn and nearby, alongside new openings and fit-only work. Postcode BT27 and its neighbours are all within our cover.

Guide price from £1,795 · Supply & fit

Lisburn guide prices

Pair of windows

£1,795 – £2,745including VAT at 20%

Two roof windows into a loft room, flashings and linings

Three or four windows

£2,745 – £4,545including VAT at 20%

Bigger loft rooms or stairwells

Balcony or combination

£4,545 – £7,195including VAT at 20%

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.

Fitting across Lisburn and nearby

Looking at a property near Lisburn but not quite in it? We work across BT27, BT28 and BT17 and outwards to Belfast, Castlereagh and Newtownabbey. Give us the full postcode when you get in touch, because access, parking and the route for a large unit all depend on the exact street. Those details shape the quote for any job around Lisburn.

Your loft roof windows or ours

There are two ways to do this. Supply and fit means we source a loft roof window that suits your roof and install it, so one company answers for both the product choice and the fitting. Fit-only means you buy the unit and we install it. With fit-only, the product warranty stays with the maker or seller, and our written guarantee covers the fitting work. Both routes get the same checks on the opening, the upstand and the maker's instructions before anything is fixed.

What we do on the day

  • Insulation collars fitted so the room's insulation meets each frame
  • Rafters trimmed and doubled where the openings need them
  • Tiles or slates cut and refitted, with the roof left weathertight
  • Approved loft drawings — We work to the window positions on your approved loft drawings or agree changes with your builder first.
  • Balcony-style windows — We check the rafters and the roof pitch before recommending balcony-style windows.

A typical installation day

Arrive and agree the plan. Sheet the floor and furniture. Set up the ladder, tower or scaffold. Check the opening, the upstand or flashing, and the unit against the paperwork. Fix and pack a loft roof window level. Seal it into the roof. Line the reveal or fit the ceiling trim. Clean the glass, clear the waste, and talk you through it. That is the shape of most fitting days, and for this type of job it usually takes one to two days.

Planning, building control and Lisburn

Northern Ireland has its own rules. Permitted development for rooflights on a house requires the unit to sit below the highest part of the roof, project no more than 15 cm where the slope faces a road, and stay at least half a metre from the ridge, eaves, party wall and verge. It doesn't apply in conservation areas or within the grounds of a listed building. For building control, structural roof alterations need an application, and rooflights must meet WER Band C or 1.6 W/m²K.

Help us quote accurately

Start with your phone. Take a picture of the roof where the unit goes or already sits, then one from inside looking up. Measure what you can, even roughly. Tell us what the roof is covered with and how a fitter would reach it: ladder, garden access or scaffold. Bought it already? Send the link or spec. Add your full postcode, for example in BT27, and we can price it.

Common questions in Lisburn

Can you remove and dispose of the old rooflight?

Yes. Taking out the old unit is part of any replacement job, and it leaves with the rest of the waste unless you ask to keep it. Old domes, glass and frames go through proper waste routes. If removal turns up a rotten kerb or damaged decking, we show you what we have found and agree the repair with you before going any further.

Can you fit a rooflight in winter or when it is raining?

Yes, within limits. Cold is less of a problem than wet, because membranes, primers and sealants need a dry surface to bond. We plan fitting days around the forecast and may move a date if heavy rain is due. If the roof has to be opened up, it is not left overnight without a temporary weather seal, so the room below stays dry while the work is finished.

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.

Tell us your postcode, BT27 or close by, and what you want fitted. We will reply with the next steps and a quote.

Rear extension at dusk with lit rooflights and a roof lantern
Ready when you are

Loft roof windows in Lisburn

Send photos and rough sizes, or ask for a survey for install work. One fixed written price before anything starts.

CallGet a quote