Steel BeamInstallers
Rear wall opened for wide doors with a galvanised steel beam and props, garden beyond

Bi-fold & sliding door openings · Larne

Bi-fold & sliding door openings in Larne

Bi-fold & sliding door openings for homes in BT40, designed by a structural engineer.

  • Free survey visit in Larne
  • Engineer's calculations arranged
  • Building control handled for you

Free survey in Larne

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  • Free survey visit
  • Engineer's calculations arranged
  • Building control handled
  • Fixed written price once scope is agreed
  • England, Wales, mainland Scotland & NI

Bi-fold & sliding door openings in Larne: how it works

For homes in Larne and the BT40 district, we handle bi-fold & sliding door openings from survey to sign-off. We also cover the surrounding towns and villages in Mid and East Antrim. The beam is sized by a structural engineer and inspected before it is boxed in.

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

  • Width, what sits above, whether columns or a goalpost are needed, outer leaf support, threshold works and how much brickwork needs matching all affect the price. The doors themselves are normally supplied separately unless agreed otherwise.
  • 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.
  • Level or flush thresholds are popular with bi-fold doors, but the floor inside and the patio outside need planning together. Drainage at the threshold and a proper damp-proof detail stop water running in when the outside is close to floor level.
  • Door suppliers quote a structural opening size, which allows for the frame and fixing tolerances. Agreeing that size before the steel is designed avoids reveals that are too tight or gaps that have to be packed out later.
  • 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.

What happens, step by step

  1. Look and measure

    We check the wall, the span you want and what the wall is carrying, and photograph anything the engineer needs to see.

  2. Design and price

    Calculations come back from the engineer and we confirm your fixed written price, line by line.

  3. Building control

    A full plans application or building notice goes to Mid and East Antrim Borough Council under the Building Regulations (Northern Ireland) 2012 before work begins.

  4. Fit, inspect, finish

    The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.

How much should I budget in Larne?

As a guide, budget £2,150–£6,000 including VAT for rear wall opening for bi-fold or sliding doors in Larne, based on published UK cost guides adjusted for prices in Northern Ireland (-14%).

JobTypical guide rangeWhat it usually covers
Rear wall opening for bi-fold or sliding doors£2,150–£6,000External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
RSJ supply and fit (single beam)£690–£2,150 per beamBeam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced separately)
Lintel replacement£340–£1,030 per lintelPropping, removing the old lintel, new lintel set on beds and brickwork made good
Opening into a rear extension£2,150–£6,000Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build

Figures include our approximate regional adjustment for prices in Northern Ireland (-14%) and are rounded. How these figures are worked out.

Approvals in Larne

Building control in Larne is run by Mid and East Antrim Borough Council. Beams and new openings are controlled work under the Northern Ireland regulations, so we apply before anything is removed and the steel is inspected before it is covered.

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.

Building rules in Northern Ireland

Bi-fold & sliding door openings near Larne

Questions about bi-fold & sliding door openings in Larne

Who approves bi-fold & sliding door openings in Larne?

Structural work in Larne needs a full plans application or building notice to Mid and East Antrim Borough Council. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.

What happens at the survey visit in Larne?

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.

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.

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 wide can a bi-fold door opening be?

There is no fixed limit, as it depends on the loads above and what the beam can bear on. The engineer designs the steel and, for very wide openings or ones near a corner, may specify columns or a goalpost frame. The door system's own maximum panel sizes and configurations also need checking.

Can I stay at home while the work is done in Larne?

Usually, yes. The work area is screened and floors are protected. The rooms either side of the opening are out of action for a few days, and there is some noise and dust while the masonry comes out.

Planning to take a wall out?

Book a free survey visit. You get an itemised written quote covering calculations, building control, steel and making good.