Steel BeamInstallers
Rear extension under construction with a steel beam over the opening into the house

Rear extension steels · Wembley

Rear extension steels in Wembley

Rear extension steels in Wembley, from free survey to completion certificate.

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

Free survey in Wembley

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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

Planning rear extension steels in Wembley

For homes in Wembley and the HA0, HA1, HA3, HA9 and NW10 districts, we handle rear extension steels from survey to sign-off. The wider London area is covered as well. The beam is sized by a structural engineer and inspected before it is boxed in.

We work alongside your builder or as the steel package within the wider build. We arrange the engineer's design, coordinate building control, prop and open the rear wall at the right stage of the programme, and fit and pack the steels so the extension can be finished around them.

Worth knowing before you start

  • In terraced and semi-detached houses one end of the beam often bears into the party wall. In England and Wales that is notifiable under the Party Wall etc. Act 1996, and the extension's own foundations near the boundary may need notices as well.
  • Opening the rear wall is usually the dustiest stage of an extension project. The work face is sheeted off from the rest of the house, and the kitchen is often out of use for a few days while the opening is formed and the steel goes in.
  • The steelwork forms part of the extension's building regulations approval, and the engineer's calculations go in with it. Planning for the extension itself is separate; many rear extensions to houses in England fall within permitted development, subject to size limits and conditions.
  • Where the extension ceiling and the house ceiling should run through at one level, the steel may need setting higher into the floor zone or tying in with the extension roof structure. That choice changes the steel design, so it is settled before calculations.
  • Soil stacks, waste pipes, boiler flues and gas meters are often fixed to the back wall. These are moved before the wall opens, and any work on gas pipework must by law be carried out by a Gas Safe registered engineer.

What happens, step by step

  1. Free visit

    A short visit to Wembley 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 rear extension steels cost in Wembley?

As a guide, budget £3,200–£8,950 including VAT for opening into a rear extension in Wembley, based on published UK cost guides adjusted for London prices (+28%).

JobTypical guide rangeWhat it usually covers
Opening into a rear extension£3,200–£8,950Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build
Rear wall opening for bi-fold or sliding doors£3,200–£8,950External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
Structural calculations for a beam£320–£960Site measure or photos, beam and padstone design and calculations for building control
Steel column or post£640–£1,920 per columnColumn supplied and fitted with base and cap plates on a pad foundation

Figures include our approximate regional adjustment for London prices (+28%) and are rounded. How these figures are worked out.

Building rules for Wembley

For Wembley, building control is provided by the local council's building control team, or by a registered building control approver if preferred. We send them the engineer's calculations with a building notice or full plans application and book the inspections. Work done without approval can cause problems at sale and is far dearer to put right later.

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

Rear extension steels near Wembley

Rear extension steels in Wembley: your questions

How much do rear extension steels cost in Wembley?

As a guide, budget £3,200–£8,950 including VAT for opening into a rear extension in Wembley, based on published UK cost guides adjusted for London prices (+28%). 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 you cover Wembley for rear extension steels?

Yes. We carry out rear extension steels in Wembley and the HA0, HA1, HA3, HA9 and NW10 postcode districts. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.

How wide can a rear extension opening be?

There is no fixed limit, and openings across the full width of a house are common with the right steel. The engineer sizes the beam or frame for the span and the loads above. Wider spans need deeper or heavier steel and possibly columns, which affects headroom and cost.

Who designs the steels for a rear extension?

A structural engineer. Your architect's drawings show the layout, but the engineer calculates the beams, columns, connections and foundations. We arrange those calculations, or work from an engineer's design you already have, and make sure the details suit the builder's programme.

Do I need a party wall agreement for extension steels?

In England and Wales, if a beam bears into a wall shared with a neighbour, or the extension foundations are dug close to theirs, notice under the Party Wall etc. Act 1996 is usually required. We can arrange the notices through a party wall surveyor. There is no equivalent legislation in Scotland or Northern Ireland.

Who approves rear extension steels in Wembley?

Structural work in Wembley needs a building notice or full plans application to the local council's building control team or a registered building control approver. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.

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.