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

Rear extension steels · Pembroke

Rear extension steels in Pembroke

Rear extension steels for homes in SA71, SA72, designed by a structural engineer.

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

Free survey in Pembroke

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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 Pembroke: how it works

Planning rear extension steels in Pembroke? Our team covers SA71 and SA72 and the streets around them. The wider Pembrokeshire area is covered as well. You get one written quote for the calculations, approvals, propping, steel and making good.

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.

Things to plan for

  • 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.
  • During the opening, props stand both inside the house and within the extension footprint. Where props bear on a newly laid slab, the propping plan checks that the slab can take those point loads, using spreaders where needed.
  • The opening is usually formed once the extension walls and roof are up, so the house stays secure and dry. Leaving it too late can hold up plastering and floor screeding, so the steel date is agreed with the builder early on.
  • 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.
  • 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.

Four stages, one team

  1. Look and measure

    We check the wall, the span you want and what the wall is carrying, and photograph anything the engineer needs to see.

  2. Design and price

    Calculations come back from the engineer and we confirm your fixed written price, line by line.

  3. Building control

    We submit the application or notice to Pembrokeshire County Council under the Building Regulations as they apply in Wales, before work starts.

  4. Fit, inspect, finish

    The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.

Guide prices for rear extension steels in Pembroke

As a guide, budget £2,300–£6,350 including VAT for opening into a rear extension in Pembroke, based on published UK cost guides adjusted for prices in Wales (-9%).

JobTypical guide rangeWhat it usually covers
Opening into a rear extension£2,300–£6,350Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build
Side return extension steelwork£3,200–£7,750Beams and posts along the old side wall line, propping and approvals (extension build extra)
Steel column or post£460–£1,360 per columnColumn supplied and fitted with base and cap plates on a pad foundation
Steel goalpost frame£1,800–£5,450Two posts and a beam bolted as a frame, pad foundations, base plates and fitting

Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.

Building rules for Pembroke

In Wales, structural alterations come under the Building Regulations 2010 as they apply in Wales. Pembrokeshire County Council handles building control for Pembroke. For work started or approved from 1 July 2026, the Welsh system uses an application to building control, dutyholders appointed in writing, a commencement notice before work starts and a compliance statement at the end.

The Party Wall etc. Act 1996 applies in Wales as well as England, so a beam bearing into a shared wall needs a party structure notice at least two months before work starts. We arrange notices through a party wall surveyor.

Building rules in Wales

Rear extension steels near Pembroke

Rear extension steels in Pembroke: your questions

Do you also work near Pembroke?

Yes. We also cover nearby towns including Pembroke Dock, Milford Haven, Haverfordwest and Tenby.

Can you work on older or listed homes in Pembroke?

Yes. Older homes often have lime mortar, timber lintels or shallow footings, which the engineer allows for. Listed buildings need listed building consent for internal structural changes as well as building regulations approval, and that must be in place first.

Will my kitchen be out of action while the rear wall is opened?

For a few days, usually. The kitchen often sits against the rear wall, so units, sinks or appliances near the opening may need disconnecting while the wall is propped and removed. The work area is sheeted off and the rest of the house stays in use.

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.

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 rear extension steels in Pembroke?

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.

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.