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

Bi-fold & sliding door openings · Greater Manchester

Bi-fold & sliding door openings in Greater Manchester

Calculations, approvals, propping, steel and making good for bi-fold & sliding door openings across Greater Manchester.

  • Survey, design and installation in one
  • Covering BL0, BL1, BL2, BL3
  • Inspected before it is covered

Free survey in Greater Manchester

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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 Greater Manchester: how it works

Bi-fold and sliding door openings are wide gaps formed in an external wall, usually at the back of the house, to take a run of folding or sliding glazed doors. A steel beam carries the wall, floor and roof loads above, and it is designed stiff enough that its movement does not press on the glass or stop the doors running.

If you are planning bi-fold & sliding door openings in Greater Manchester, the order of work matters as much as the steel: survey, calculations, approval, propping, installation, inspection and making good. We work in Middleton, Rochdale and Stockport and the surrounding villages. We run that sequence for you as one job with one point of contact.

What to expect

  • 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.
  • 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.
  • 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.
  • 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.

What happens, step by step

  1. Free visit

    A short visit to Greater Manchester to see the job, agree what you want and check the bearings, floors and services that affect the design.

  2. Calculations

    The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.

  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. 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 Greater Manchester?

As a guide, budget £2,400–£6,700 including VAT for rear wall opening for bi-fold or sliding doors in Greater Manchester, based on published UK cost guides adjusted for prices in the North West (-4%).

JobTypical guide rangeWhat it usually covers
Rear wall opening for bi-fold or sliding doors£2,400–£6,700External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
RSJ supply and fit (single beam)£770–£2,400 per beamBeam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced separately)
Steel goalpost frame£1,900–£5,750Two posts and a beam bolted as a frame, pad foundations, base plates and fitting
Lintel replacement£380–£1,150 per lintelPropping, removing the old lintel, new lintel set on beds and brickwork made good

Figures include our approximate regional adjustment for prices in the North West (-4%) and are rounded. How these figures are worked out.

Building rules for Greater Manchester

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 in Greater Manchester: your questions

How soon can bi-fold & sliding door openings start in Greater Manchester?

Start dates depend on the engineer's calculations, the building control approval and, where needed, party wall notice periods. We give you a realistic timetable after the survey and keep you updated as each approval comes through.

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

As a guide, budget £2,400–£6,700 including VAT for rear wall opening for bi-fold or sliding doors in Greater Manchester, based on published UK cost guides adjusted for prices in the North West (-4%). 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.

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.

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.

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.

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.