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

Rear extension steels · Dunstable

Rear extension steels in Dunstable

Rear extension steels for homes in LU5, LU6, designed by a structural engineer.

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

Free survey in Dunstable

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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

Rear extension steels in Dunstable: how it works

We cover rear extension steels in Dunstable (LU5, LU6) and the streets around it. We also work in nearby Luton, roughly 4.5 miles away. Each job is designed by a structural engineer and approved through Central Bedfordshire Council before work begins.

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.

Key points for your project

  • The original rear wall of most houses is load-bearing because it supports first-floor joists and the bedroom wall above. Even where the joists run parallel to it, the masonry overhead still needs carrying, so steel is almost always part of opening it up.
  • A single beam works where solid masonry is left at both ends of the opening. Where the opening runs nearly the full width or the corners are weak, the engineer may use columns or a goalpost frame, which is two posts and a beam bolted together.
  • 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.
  • When bi-fold or sliding doors sit directly beneath the new steel, the beam has to stay stiff enough not to bind the door panels. The engineer sets a tighter deflection limit, which can mean a deeper or heavier section than strength alone would need.
  • 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.

Four stages, one team

  1. Free visit

    A short visit to Dunstable 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 Central Bedfordshire Council, 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 Dunstable?

As a guide, budget £2,650–£7,400 including VAT for opening into a rear extension in Dunstable, based on published UK cost guides adjusted for prices in the East of England (+6%).

JobTypical guide rangeWhat it usually covers
Opening into a rear extension£2,650–£7,400Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build
Steel column or post£530–£1,590 per columnColumn supplied and fitted with base and cap plates on a pad foundation
Structural calculations for a beam£260–£800Site measure or photos, beam and padstone design and calculations for building control
Party wall surveyor (agreed surveyor, per neighbour)£950–£2,120 per neighbourSchedule of condition and award where a neighbour dissents; serving notice alone, where the neighbour consents, costs far less (England and Wales only)

Figures include our approximate regional adjustment for prices in the East of England (+6%) and are rounded. How these figures are worked out.

Building rules for Dunstable

Structural openings in English homes need building regulations approval before work starts. Central Bedfordshire Council 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

Rear extension steels near Dunstable

Questions about rear extension steels in Dunstable

What happens at the survey visit in Dunstable?

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.

How soon can rear extension steels start in Dunstable?

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.

Can I have a flat ceiling between the house and the extension?

Often, yes, but it depends on the floor depth above and the loads involved. The steel can sometimes be set up into the floor zone so the ceiling runs through level, which usually means more work to the joists. This needs deciding before the engineer designs the steel.

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.

Do I need a steel beam for my rear extension?

If the original back wall is being opened up into the extension, almost certainly yes. That wall normally carries the first floor and the wall above, so a beam, columns or a goalpost frame takes over the job. A structural engineer confirms exactly what is needed once the opening width and loads are known.

How much do rear extension steels cost in Dunstable?

As a guide, budget £2,650–£7,400 including VAT for opening into a rear extension in Dunstable, based on published UK cost guides adjusted for prices in the East of England (+6%). 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.

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.