Rear extension steels · Chiswick
Rear extension steels in Chiswick
Rear extension steels in Chiswick, from free survey to completion certificate.
- Free survey visit in Chiswick
- Engineer's calculations arranged
- Building control handled for you
- 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 Chiswick
We carry out rear extension steels in Chiswick, covering the SW13, SW14, TW8, W3 and W4 postcode districts. The wider London area is covered as well. The job starts with a free survey visit so the engineer's calculations are based on your actual walls, floors and loads.
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.
Worth knowing before you start
- 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.
- 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.
- The steelwork forms part of the extension's building regulations approval, and the engineer's calculations go in with it. Planning for the extension itself is separate; many rear extensions to houses in England fall within permitted development, subject to size limits and conditions.
- 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.
From survey to sign-off in Chiswick
Survey in Chiswick
We visit, look at the wall and what sits above it, measure the opening and note services, access and how the steel can be brought in.
Engineer's design
A structural engineer sizes the beam, padstones and any posts, and sets out the temporary support needed while the wall is out.
Building control
We submit a building notice or full plans application to the local council's building control team, so approval is in place before the wall is touched.
Install and sign-off
Props go in, the opening is formed, the steel is set and packed, building control inspects it, and we make good.
What do rear extension steels cost in Chiswick?
As a guide, budget £3,200–£8,950 including VAT for opening into a rear extension in Chiswick, based on published UK cost guides adjusted for London prices (+28%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Opening into a rear extension | £3,200–£8,950 | Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build |
| Steel column or post | £640–£1,920 per column | Column supplied and fitted with base and cap plates on a pad foundation |
| Structural calculations for a beam | £320–£960 | Site measure or photos, beam and padstone design and calculations for building control |
| Rear wall opening for bi-fold or sliding doors | £3,200–£8,950 | External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately) |
Figures include our approximate regional adjustment for London prices (+28%) and are rounded. How these figures are worked out.
Building control and neighbours in Chiswick
For Chiswick, building control is provided by the local council's building control team, or by a registered building control approver if preferred. We send them the engineer's calculations with a building notice or full plans application and book the inspections. Work done without approval can cause problems at sale and is far dearer to put right later.
If the beam bears into a wall you share with a neighbour, the Party Wall etc. Act 1996 applies, and a party structure notice must be served at least two months before that work starts. We arrange this through a party wall surveyor.
Rear extension steels near Chiswick
- Acton 1.4 mi
- Barnes 1.4 mi
- Shepherds Bush 1.8 mi
- Notting Hill 2.6 mi
- Fulham 2.7 mi
- Putney 2.8 mi
Questions about rear extension steels in Chiswick
What happens at the survey visit in Chiswick?
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.
How much do rear extension steels cost in Chiswick?
As a guide, budget £3,200–£8,950 including VAT for opening into a rear extension in Chiswick, based on published UK cost guides adjusted for London prices (+28%). The exact figure depends on the span, what the wall carries, access and the finish, and is fixed in writing once the scope is agreed.
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.
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.
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 control 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.