Rear extension steels · Gelligaer
Rear extension steels in Gelligaer
Rear extension steels for homes in CF81, CF82, NP12, designed by a structural engineer.
- Itemised written quote
- Beam sized by a structural engineer
- Covering Gelligaer and nearby
- 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 Gelligaer
Planning rear extension steels in Gelligaer? Our team covers CF81, CF82 and NP12 and the streets around them. Our coverage runs across Caerphilly, so nearby villages are included too. You get one written quote for the calculations, approvals, propping, steel and making good.
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.
Things to plan for
- 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.
- 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.
- 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.
- 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.
- Two-storey rear extensions add a second level of loads to think about. Steels at first-floor level may carry the existing rear wall of the bedrooms or tie the new roof into the old one, so the engineer looks at both floors together.
From survey to sign-off in Gelligaer
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.
Design and price
Calculations come back from the engineer and we confirm your fixed written price, line by line.
Building control
We submit the application or notice to Caerphilly County Borough Council under the Building Regulations as they apply in Wales, before work starts.
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 Gelligaer
As a guide, budget £2,300–£6,350 including VAT for opening into a rear extension in Gelligaer, based on published UK cost guides adjusted for prices in Wales (-9%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Opening into a rear extension | £2,300–£6,350 | Original 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 | £2,300–£6,350 | External 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 column | Column supplied and fitted with base and cap plates on a pad foundation |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building control |
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 Gelligaer
Removing a load-bearing wall in Wales needs approval under the Welsh building regulations before work starts. For Gelligaer the application goes to Caerphilly 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.
Rear extension steels in Gelligaer: your questions
Do you cover Gelligaer for rear extension steels?
Yes. We carry out rear extension steels in Gelligaer and the CF81, CF82 and NP12 postcode districts. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.
What happens at the survey visit in Gelligaer?
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.
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 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.
Who approves rear extension steels in Gelligaer?
Structural work in Gelligaer needs a building control application to Caerphilly 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.