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

Bi-fold & sliding door openings · Andover

Bi-fold & sliding door openings in Andover

Bi-fold & sliding door openings in Andover, from free survey to completion certificate.

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

Free survey in Andover

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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 Andover

For homes in Andover and the SP10 and SP11 districts, we handle bi-fold & sliding door openings from survey to sign-off. The wider Hampshire 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.

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.
  • 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.
  • 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.
  • External walls can have gas meters, boiler flues, soil pipes, outside taps or cables near the new opening. These are found at survey and moved by the right trade, with any gas pipework done by a Gas Safe registered engineer as the law requires.
  • 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.

What happens, step by step

  1. Free visit

    A short visit to Andover 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.

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

As a guide, budget £2,800–£7,850 including VAT for rear wall opening for bi-fold or sliding doors in Andover, 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)
Structural calculations for a beam£280–£840Site measure or photos, beam and padstone design and calculations for building control
RSJ supply and fit (single beam)£900–£2,800 per beamBeam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced 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

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

Building rules for Andover

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.

If the beam bears into a wall you share with a neighbour, the Party Wall etc. Act 1996 applies, and a party structure notice must be served at least two months before that work starts. We arrange this through a party wall surveyor.

Building rules in England

Bi-fold & sliding door openings near Andover

Questions about bi-fold & sliding door openings in Andover

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

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

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.

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.

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.

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.