Rear extension steels · Sunbury-on-Thames
Rear extension steels in Sunbury-on-Thames
Rear extension steels in Sunbury-on-Thames, from free survey to completion certificate.
- Itemised written quote
- Beam sized by a structural engineer
- Covering Sunbury-on-Thames and nearby
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
Planning rear extension steels in Sunbury-on-Thames
If you live in Sunbury-on-Thames, rear extension steels can usually be planned and priced after a single survey visit. We also work in nearby Woking, roughly 8.5 miles away. We cover KT8, KT12, KT13, TW15 and TW16, and we fix the price in writing once the layout and scope are agreed.
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
- 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.
- 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.
- 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.
- 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.
- In terraced and semi-detached houses one end of the beam often bears into the party wall. In England and Wales that is notifiable under the Party Wall etc. Act 1996, and the extension's own foundations near the boundary may need notices as well.
From survey to sign-off in Sunbury-on-Thames
Free visit
A short visit to Sunbury-on-Thames 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 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.
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 Sunbury-on-Thames
As a guide, budget £2,800–£7,850 including VAT for opening into a rear extension in Sunbury-on-Thames, based on published UK cost guides adjusted for prices in the South East (+12%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Opening into a rear extension | £2,800–£7,850 | Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build |
| Structural calculations for a beam | £280–£840 | Site measure or photos, beam and padstone design and calculations for building control |
| Rear wall opening for bi-fold or sliding doors | £2,800–£7,850 | External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately) |
| Party wall surveyor (agreed surveyor, per neighbour) | £1,000–£2,250 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) |
Figures include our approximate regional adjustment for prices in the South East (+12%) and are rounded. How these figures are worked out.
Approvals in Sunbury-on-Thames
In England, taking out a load-bearing wall or putting in a beam is building work under the Building Regulations 2010. It needs approval from building control, either the local council's building control team or a registered building control approver, through a full plans application or a building notice. Part A covers the structure and Part B covers fire safety, which is why steel in homes is usually fire protected.
Terraced and semi-detached homes often need party wall notices, because cutting into a shared wall to take a beam end is notifiable under the Party Wall etc. Act 1996. Allow at least two months for the notice period unless your neighbour agrees sooner.
Questions about rear extension steels in Sunbury-on-Thames
How soon can rear extension steels start in Sunbury-on-Thames?
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.
How much do rear extension steels cost in Sunbury-on-Thames?
As a guide, budget £2,800–£7,850 including VAT for opening into a rear extension in Sunbury-on-Thames, based on published UK cost guides adjusted for prices in the South East (+12%). 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.
How wide can a rear extension opening be?
There is no fixed limit, and openings across the full width of a house are common with the right steel. The engineer sizes the beam or frame for the span and the loads above. Wider spans need deeper or heavier steel and possibly columns, which affects headroom and cost.
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.
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.
Do I need a party wall agreement for rear extension steels in Sunbury-on-Thames?
Yes, if the beam bears into a shared wall: the Party Wall etc. Act 1996 applies in England and Wales, and a party structure notice must be served at least two months before that work starts. We arrange it through a party wall surveyor.