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

Bi-fold & sliding door openings · Llandeilo

Bi-fold & sliding door openings in Llandeilo

Steelwork, approvals and making good for bi-fold & sliding door openings in Llandeilo and nearby.

  • Price fixed in writing once scope is agreed
  • Building control arranged
  • Temporary works and making good included

Free survey in Llandeilo

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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 Llandeilo: how it works

For homes in Llandeilo and the SA19 district, we handle bi-fold & sliding door openings from survey to sign-off. The wider Carmarthenshire area is covered as well. 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.

Worth knowing before you start

  • 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.
  • The structural work for a typical bi-fold opening usually takes three to five working days. Doors are often made to order, so the steel goes in once opening sizes are confirmed and the doors are fitted soon after.
  • 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.
  • 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.
  • Both leaves of a cavity wall need support over the opening. Depending on the design, the outer brickwork may sit on a plate fixed to the beam or on a separate external lintel, and the engineer specifies which suits the loads and the look.

What happens, step by step

  1. Survey in Llandeilo

    We visit, look at the wall and what sits above it, measure the opening and note services, access and how the steel can be brought in.

  2. Engineer's design

    A structural engineer sizes the beam, padstones and any posts, and sets out the temporary support needed while the wall is out.

  3. Building control

    We submit the application or notice to Carmarthenshire County Council under the Building Regulations as they apply in Wales, before work starts.

  4. Install and sign-off

    Props go in, the opening is formed, the steel is set and packed, building control inspects it, and we make good.

What do bi-fold & sliding door openings cost in Llandeilo?

As a guide, budget £2,300–£6,350 including VAT for rear wall opening for bi-fold or sliding doors in Llandeilo, based on published UK cost guides adjusted for prices in Wales (-9%).

JobTypical guide rangeWhat it usually covers
Rear wall opening for bi-fold or sliding doors£2,300–£6,350External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
RSJ supply and fit (single beam)£730–£2,280 per beamBeam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced separately)
Lintel replacement£360–£1,090 per lintelPropping, removing the old lintel, new lintel set on beds and brickwork made good
Steel goalpost frame£1,800–£5,450Two posts and a beam bolted as a frame, pad foundations, base plates and fitting

Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.

Building rules for Llandeilo

Removing a load-bearing wall in Wales needs approval under the Welsh building regulations before work starts. For Llandeilo the application goes to Carmarthenshire County Council or a registered building control approver, with the engineer's calculations, and a completion certificate follows the final inspection.

Where the steel bears into a wall shared with next door, notice must be served under the Party Wall etc. Act 1996. If your neighbour dissents, surveyors agree how the work is done before it starts.

Building rules in Wales

Bi-fold & sliding door openings near Llandeilo

Local questions answered

Do I need a party wall agreement for bi-fold & sliding door openings in Llandeilo?

Yes, if the beam bears into a shared wall: the Party Wall etc. Act 1996 applies in England and Wales, and a party structure notice must be served at least two months before that work starts. We arrange it through a party wall surveyor.

How much do bi-fold & sliding door openings cost in Llandeilo?

As a guide, budget £2,300–£6,350 including VAT for rear wall opening for bi-fold or sliding doors in Llandeilo, based on published UK cost guides adjusted for prices in Wales (-9%). 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.

Should I order my doors before the opening is made?

It helps to choose them first. The supplier's structural opening size and threshold detail feed into the steel design, so the opening is formed to suit the doors exactly. Many people order once the engineer has confirmed the opening, then time the structural work so the gap is weathered for as short a time as possible.

Why does the beam need to be stiffer for glazed doors?

Because glazed doors tolerate very little movement. Every beam bends slightly under load, and with bi-folds or sliders that movement can make panels bind, tracks drag or glass crack. The engineer sets a stricter deflection limit for these openings, which often means a heavier section than strength alone would need.

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.

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.