Rear extension steels · Lisburn and Castlereagh
Rear extension steels in Lisburn and Castlereagh
Survey, engineer's design and installation of rear extension steels anywhere in Lisburn and Castlereagh.
- Survey, design and installation in one
- Covering BT16, BT17, BT26, BT27
- 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 Lisburn and Castlereagh
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.
Looking for rear extension steels in Lisburn and Castlereagh? Towns we cover include Lisburn, among other places in the area. Our teams handle the calculations, the building control approval, the propping and the steel itself, and leave the opening ready for plastering and decoration.
Things to plan for
- 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.
- 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.
- 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.
- The opening is usually formed once the extension walls and roof are up, so the house stays secure and dry. Leaving it too late can hold up plastering and floor screeding, so the steel date is agreed with the builder early on.
How the job runs in Lisburn and Castlereagh
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
A full plans application or building notice goes to Lisburn and Castlereagh City Council under the Building Regulations (Northern Ireland) 2012 before work begins.
Fit, inspect, finish
The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.
How much should I budget in Lisburn and Castlereagh?
As a guide, budget £2,150–£6,000 including VAT for opening into a rear extension in Lisburn and Castlereagh, based on published UK cost guides adjusted for prices in Northern Ireland (-14%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Opening into a rear extension | £2,150–£6,000 | Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build |
| Steel column or post | £430–£1,290 per column | Column supplied and fitted with base and cap plates on a pad foundation |
| Rear wall opening for bi-fold or sliding doors | £2,150–£6,000 | External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately) |
| Side return extension steelwork | £3,000–£7,300 | Beams and posts along the old side wall line, propping and approvals (extension build extra) |
Figures include our approximate regional adjustment for prices in Northern Ireland (-14%) and are rounded. How these figures are worked out.
Building rules for Lisburn and Castlereagh
Building control in Lisburn and Castlereagh is run by Lisburn and Castlereagh City Council. Beams and new openings are controlled work under the Northern Ireland regulations, so we apply before anything is removed and the steel is inspected before it is covered.
The Party Wall etc. Act does not extend to Northern Ireland. Shared walls are dealt with under your title and the general law, so we recommend agreeing access and the work with your neighbour before it starts.
Rear extension steels by town
Rear extension steels in Lisburn and Castlereagh: your questions
Do you cover Lisburn and Castlereagh for rear extension steels?
Yes. We carry out rear extension steels in Lisburn and Castlereagh. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.
How much do rear extension steels cost in Lisburn and Castlereagh?
As a guide, budget £2,150–£6,000 including VAT for opening into a rear extension in Lisburn and Castlereagh, based on published UK cost guides adjusted for prices in Northern Ireland (-14%). 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.
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.
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.
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.
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.