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

Rear extension steels · Horsham

Rear extension steels in Horsham

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

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

Free survey in Horsham

Tell us about the rear extension steel job in Horsham.

Please enter your name.
Please enter a UK phone number.
Please enter a valid email.
Please enter a UK postcode.
Please tell us a little about the job.
  • Free survey visit
  • Engineer's calculations arranged
  • Building control handled
  • Fixed written price once scope is agreed
  • England, Wales, mainland Scotland & NI

About our rear extension steels service in Horsham

If you live in Horsham, rear extension steels can usually be planned and priced after a single survey visit. Horsham is around 7.2 miles from Crawley, and we cover both. We cover RH12 and RH13, and we fix the price in writing once the layout and scope are agreed.

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.

What to expect

  • Columns carry concentrated loads, so each normally sits on a pad foundation designed by the engineer. Digging these inside an existing kitchen or through a solid concrete floor takes planning, especially where drains run close to the back wall.
  • 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.
  • The building control completion certificate for the extension covers the steelwork to the old rear wall. Keep it with the engineer's calculations and drawings, as a buyer's solicitor will expect to see the structural paperwork for the extension.
  • 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.
  • 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.

From survey to sign-off in Horsham

  1. Free visit

    A short visit to Horsham 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 Horsham?

As a guide, budget £2,800–£7,850 including VAT for opening into a rear extension in Horsham, based on published UK cost guides adjusted for prices in the South East (+12%).

JobTypical guide rangeWhat it usually covers
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
Steel column or post£560–£1,680 per columnColumn supplied and fitted with base and cap plates on a pad foundation

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 Horsham

For Horsham, 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.

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

Rear extension steels near Horsham

Local questions answered

Do I need a party wall agreement for rear extension steels 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.

What happens at the survey visit in Horsham?

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 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.

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.

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.

How soon can rear extension steels start in Horsham?

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.

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.