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

Bi-fold & sliding door openings · Horsham

Bi-fold & sliding door openings in Horsham

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

  • Itemised written quote
  • Beam sized by a structural engineer
  • Covering Horsham and nearby

Free survey in Horsham

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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

About our bi-fold & sliding door openings service in Horsham

Our bi-fold & sliding door openings service in Horsham covers everything from the first visit to the completion paperwork. Horsham is around 7.2 miles from Crawley, and we cover both. Postcode districts we cover here include RH12 and RH13.

We coordinate the structure with your door supplier's sizes, so the finished opening matches the frame. The survey visit, structural calculations from a qualified engineer, building control, propping, steel, cavity trays, weather protection while the wall is open and making good are all covered in one itemised written quote.

What to expect

  • New brickwork at the reveals and above the opening should match the existing in colour, size and bond. Sound bricks from the wall being removed are often cleaned and reused, and the mortar colour is matched as closely as possible.
  • 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.
  • 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.
  • 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.
  • 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.

Four stages, one team

  1. Survey in Horsham

    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 a building notice or full plans application to the local council's building control team, so approval is in place before the wall is touched.

  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.

Guide prices for bi-fold & sliding door openings in Horsham

As a guide, budget £2,800–£7,850 including VAT for rear wall opening for bi-fold or sliding doors in Horsham, based on published UK cost guides adjusted for prices in the South East (+12%).

JobTypical guide rangeWhat it usually covers
Rear wall opening for bi-fold or sliding doors£2,800–£7,850External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
Opening into a rear extension£2,800–£7,850Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build
Steel goalpost frame£2,250–£6,700Two posts and a beam bolted as a frame, pad foundations, base plates and fitting
Structural calculations for a beam£280–£840Site measure or photos, beam and padstone design and calculations for building control

Figures include our approximate regional adjustment for prices in the South East (+12%) and are rounded. How these figures are worked out.

Approvals in Horsham

Structural openings in English homes need building regulations approval before work starts. The local council's building control team can deal with it, or you can use a registered building control approver. Either way the steel is inspected before it is covered, and a completion certificate is issued at the end. Keep it safe for when you sell.

Terraced and semi-detached homes often need party wall notices, because cutting into a shared wall to take a beam end is notifiable under the Party Wall etc. Act 1996. Allow at least two months for the notice period unless your neighbour agrees sooner.

Building rules in England

Bi-fold & sliding door openings near Horsham

Local questions answered

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

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.

Do you also work near Horsham?

Yes. We also cover nearby towns including Crawley, Horley, Haywards Heath and Burgess Hill.

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.

Do I need a steel beam for bi-fold doors?

Usually, yes. Bi-fold and sliding doors need wide openings, and in a load-bearing external wall that span is normally carried on steel. The engineer designs it for strength and stiffness, because glazed doors can stick or be damaged if the beam deflects. A small opening under light loads might only need a lintel, but that is the engineer's call.

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.

Do you cover Horsham for bi-fold & sliding door openings?

Yes. We carry out bi-fold & sliding door openings in Horsham and the RH12 and RH13 postcode districts. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.

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.