Rear extension steels · Bangor
Rear extension steels in Bangor, Gwynedd
Rear extension steels in Bangor, Gwynedd, from free survey to completion certificate.
- Price fixed in writing once scope is agreed
- Building control arranged
- Temporary works and making good included
- 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 Bangor, Gwynedd: how it works
Our rear extension steels service in Bangor, Gwynedd covers everything from the first visit to the completion paperwork. We also cover the surrounding towns and villages in Gwynedd. Postcode districts we cover here include LL57.
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
- 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 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.
- 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.
- Soil stacks, waste pipes, boiler flues and gas meters are often fixed to the back wall. These are moved before the wall opens, and any work on gas pipework must by law be carried out by a Gas Safe registered engineer.
How the job runs in Bangor, Gwynedd
Free visit
A short visit to Bangor, Gwynedd to see the job, agree what you want and check the bearings, floors and services that affect the design.
Calculations
The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.
Building control
We submit the application or notice to Cyngor Gwynedd under the Building Regulations as they apply in Wales, before work starts.
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 Bangor, Gwynedd
As a guide, budget £2,300–£6,350 including VAT for opening into a rear extension in Bangor, Gwynedd, 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 |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building control |
| Party wall surveyor (agreed surveyor, per neighbour) | £820–£1,820 per neighbour | Schedule of condition and award where a neighbour dissents; serving notice alone, where the neighbour consents, costs far less (England and Wales only) |
| Side return extension steelwork | £3,200–£7,750 | Beams and posts along the old side wall line, propping and approvals (extension build extra) |
Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.
Building rules for Bangor, Gwynedd
In Wales, structural alterations come under the Building Regulations 2010 as they apply in Wales. Cyngor Gwynedd handles building control for Bangor, Gwynedd. 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.
Rear extension steels near Bangor
- Menai Bridge 1.5 mi
- Llangefni 7.8 mi
- Caernarfon 8.6 mi
- Llandudno 14.0 mi
- Amlwch 15.4 mi
- Colwyn Bay 17.3 mi
Questions about rear extension steels in Bangor, Gwynedd
What happens at the survey visit in Bangor, Gwynedd?
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 you also work near Bangor, Gwynedd?
Yes. We also cover nearby towns including Menai Bridge, Llangefni, Caernarfon and Llandudno.
When does the back wall come out during an extension build?
Usually once the extension walls and roof are up and the new space is weathertight. That keeps the house secure and dry while the opening is formed. The steel goes in, building control inspects it, and the builder then carries the floors and ceilings through.
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.
Can I use my own builder for the extension and you for the steels?
Yes. We can supply and fit the steel package while another builder handles the extension shell and finishes. Dates are agreed with them so the rear wall is opened at the right stage, and the engineer's details are shared so levels, padstones and foundations line up.
Who approves rear extension steels in Bangor, Gwynedd?
Structural work in Bangor, Gwynedd needs a building control application to Cyngor Gwynedd 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.