Bi-fold & sliding door openings · Derry/Londonderry
Bi-fold & sliding door openings in Derry/Londonderry
Bi-fold & sliding door openings for homes in BT47, BT48, designed by a structural engineer.
- Free survey visit in Derry/Londonderry
- Engineer's calculations arranged
- Building control handled for you
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
Planning bi-fold & sliding door openings in Derry/Londonderry
Our bi-fold & sliding door openings service in Derry/Londonderry covers everything from the first visit to the completion paperwork. Our coverage runs across Derry City and Strabane, so nearby villages are included too. Postcode districts we cover here include BT47 and BT48.
Replacing a window or narrow patio door with a full run of bi-fold or sliding doors opens a room to the garden. Because it is an external wall, the opening usually carries the first floor, the wall above and sometimes roof loads, and the new steel has to work with the doors as well as hold the house up.
Things to plan for
- In cavity walls a cavity tray above the new head directs any water in the cavity out through weep vents. Without it, damp can show inside above the doors, so the tray is lapped and sealed correctly as the brickwork is rebuilt.
- A wide glazed opening changes the security of the back of the house. During the works the opening is boarded at night if the doors are not yet fitted, and it is worth checking the locking and glass specification of the doors you choose.
- Replacing a rear window with doors in a house is usually permitted development, but front elevations, listed buildings, flats and homes where permitted development rights have been removed may need planning permission or another consent.
- Very wide openings, or ones that run close to the corner of the house, may leave too little wall for the beam to bear on. In that case the engineer may specify steel columns or a goalpost frame standing on its own foundations.
- Glazed doors need a stiffer beam than a plain opening of the same width. If the steel bends even slightly under load, folding panels can bind, sliders can stick and glass can be stressed, so the engineer sets a tighter deflection limit for door openings.
From survey to sign-off in Derry/Londonderry
Free visit
A short visit to Derry/Londonderry to see the job, agree what you want and check the bearings, floors and services that affect the design.
Calculations
The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.
Building control
A full plans application or building notice goes to Derry City and Strabane District Council under the Building Regulations (Northern Ireland) 2012 before work begins.
Steel in, made good
On site we prop, open up, fit and pack the steel, then fire protect, box in and plaster once the inspection is done.
How much should I budget in Derry/Londonderry?
As a guide, budget £2,150–£6,000 including VAT for rear wall opening for bi-fold or sliding doors in Derry/Londonderry, based on published UK cost guides adjusted for prices in Northern Ireland (-14%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Rear wall opening for bi-fold or sliding doors | £2,150–£6,000 | External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately) |
| Widening an internal doorway | £860–£2,150 | Opening widened with a new lintel or short beam, approval where structural, and making good |
| Lintel replacement | £340–£1,030 per lintel | Propping, removing the old lintel, new lintel set on beds and brickwork made good |
| Steel goalpost frame | £1,700–£5,150 | Two posts and a beam bolted as a frame, pad foundations, base plates and fitting |
Figures include our approximate regional adjustment for prices in Northern Ireland (-14%) and are rounded. How these figures are worked out.
Building control and neighbours in Derry/Londonderry
Removing a load-bearing wall in Northern Ireland needs building control approval from the council. Derry City and Strabane District Council covers Derry/Londonderry. The engineer's calculations support the application, and a completion certificate is issued after the final inspection.
Northern Ireland has no Party Wall Act, so there is no statutory notice to serve. Where the steel bears into a shared wall, the title deeds and the general law apply, and agreeing the work with your neighbour in writing first is good practice.
Questions about bi-fold & sliding door openings in Derry/Londonderry
How much do bi-fold & sliding door openings cost in Derry/Londonderry?
As a guide, budget £2,150–£6,000 including VAT for rear wall opening for bi-fold or sliding doors in Derry/Londonderry, based on published UK cost guides adjusted for prices in Northern Ireland (-14%). The exact figure depends on the span, what the wall carries, access and the finish, and is fixed in writing once the scope is agreed.
What happens at the survey visit in Derry/Londonderry?
We look at the wall, the floor and ceiling either side and what sits above, measure the opening you want, and note cables, pipes and access for the steel. It usually takes under an hour and there is no charge.
Do I need planning permission for bi-fold doors?
Usually not for a rear opening in a house, as this generally falls within permitted development. Planning or another consent may be needed for front elevations, flats, listed buildings, conservation areas with extra controls, or homes where permitted development rights have been removed. We flag this at survey so you can check before work is booked.
What does a bi-fold opening quote include?
Our itemised written quote covers the survey, calculations, building control, propping, removing the wall, steel and padstones, outer leaf support, cavity trays and closers, temporary weather protection and making good. Doors, threshold drainage and patio work are shown separately unless agreed. The price is fixed in writing once the opening size and specification are agreed.
How long does it take to make an opening for bi-fold doors?
The structural opening usually takes three to five working days, including propping, cutting out the wall, fitting the steel and outer leaf support, and forming the reveals. The doors can then be fitted, with inside making good and outside brickwork finishing following on. Lead times on made-to-order doors affect the overall timeline more than the steelwork.