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

Rear extension steels · Colwyn Bay

Rear extension steels in Colwyn Bay

Steelwork, approvals and making good for rear extension steels in Colwyn Bay and nearby.

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

Free survey in Colwyn Bay

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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 Colwyn Bay: how it works

Need rear extension steels in Colwyn Bay? The wider Conwy area is covered as well. We survey the property, arrange the engineer's design, deal with Conwy County Borough Council, fit the steel and make good, all under one quote for LL28 and LL29 addresses.

Building a rear extension is only half of the open-plan result. The original back wall still holds up the first floor and the rear wall of the bedrooms above, so opening it needs steel. Depending on the width and what is left to bear on, that could be a single beam on padstones, a beam on columns, or a full goalpost frame.

What to expect

  • 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 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.
  • 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.
  • In older houses the rear wall may be solid brick in lime mortar, with timber lintels and shallow footings beneath. The engineer may ask for trial holes to see what the wall stands on before deciding where the steel will bear.
  • 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.

What happens, step by step

  1. Free visit

    A short visit to Colwyn Bay 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 the application or notice to Conwy County Borough Council under the Building Regulations as they apply in Wales, before work starts.

  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.

Guide prices for rear extension steels in Colwyn Bay

As a guide, budget £2,300–£6,350 including VAT for opening into a rear extension in Colwyn Bay, 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
Steel goalpost frame£1,800–£5,450Two posts and a beam bolted as a frame, pad foundations, base plates and fitting
Rear wall opening for bi-fold or sliding doors£2,300–£6,350External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately)
Steel column or post£460–£1,360 per columnColumn supplied and fitted with base and cap plates on a pad foundation

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

Building control and neighbours in Colwyn Bay

Removing a load-bearing wall in Wales needs approval under the Welsh building regulations before work starts. For Colwyn Bay the application goes to Conwy County Borough Council or a registered building control approver, with the engineer's calculations, and a completion certificate follows the final inspection.

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 Colwyn Bay

Questions about rear extension steels in Colwyn Bay

Who approves rear extension steels in Colwyn Bay?

Structural work in Colwyn Bay needs a building control application to Conwy County Borough Council under the Welsh regulations, with a commencement notice before work starts. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.

Do you also work near Colwyn Bay?

Yes. We also cover nearby towns including Llandudno, Abergele, Rhyl and Prestatyn.

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.

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.

What is a goalpost frame in an extension?

A goalpost frame is two steel columns with a beam across the top, bolted together and standing on their own foundations. It is used where the opening is so wide that little masonry is left to bear on, or where the existing corners cannot take the load. The engineer decides whether one is needed.

How soon can rear extension steels start in Colwyn Bay?

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.