Rear extension steels · West Dunbartonshire
Rear extension steels in West Dunbartonshire
Survey, engineer's design and installation of rear extension steels anywhere in West Dunbartonshire.
- Survey, design and installation in one
- Covering G60, G81, G82, G83
- Inspected before it is covered
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
What rear extension steels involve in West Dunbartonshire
Rear extension steels are the beams, columns and frames that let the original back wall of a house be opened up into a new extension. Sized by a structural engineer, they pick up the floor, wall and roof loads that the old wall carried and pass them into bearings or foundations, so the new and old spaces join as one open room.
Rear extension steels are one of the most common structural jobs in homes across West Dunbartonshire. We can survey in places such as Dumbarton, Clydebank and Vale of Leven and the villages around them. Every job starts with a survey visit, then calculations from a structural engineer, so the steel suits the house in front of us rather than a rule of thumb.
Key points for your project
- 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.
- 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.
- 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.
- 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.
What happens, step by step
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 warrant
A building warrant is applied for from West Dunbartonshire Council, and work starts only once the warrant has been granted.
Fit, inspect, finish
The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.
What do rear extension steels cost in West Dunbartonshire?
As a guide, budget £2,300–£6,350 including VAT for opening into a rear extension in West Dunbartonshire, based on published UK cost guides adjusted for prices in Scotland (-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 |
| Side return extension steelwork | £3,200–£7,750 | Beams and posts along the old side wall line, propping and approvals (extension build extra) |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building standards |
| Steel column or post | £460–£1,360 per column | Column supplied and fitted with base and cap plates on a pad foundation |
Figures include our approximate regional adjustment for prices in Scotland (-9%) and are rounded. How these figures are worked out.
Building rules for West Dunbartonshire
Steel beam work in West Dunbartonshire needs a building warrant from West Dunbartonshire Council. The structural design is part of the application, and the council's building standards team accepts the completion certificate once the work is done as approved.
Scotland has no Party Wall Act. Work affecting a shared wall is governed by your title deeds and the general law, and in flats by the Tenements (Scotland) Act 2004, so it is sensible to agree the work with neighbours in writing before starting.
Rear extension steels by town
Local questions answered
What happens at the survey visit in West Dunbartonshire?
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 cover West Dunbartonshire for rear extension steels?
Yes. We carry out rear extension steels in West Dunbartonshire. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.
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.
Is the steel included in the extension's building regulations?
Yes. The steelwork is part of the extension, so the engineer's calculations go to building standards with the extension application and the steel is inspected before it is covered. The completion certificate issued for the extension then covers the structural work to the rear wall.
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 standards inspects it, and the builder then carries the floors and ceilings through.
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.