Rear extension steels · Derry/Londonderry
Rear extension steels in Derry/Londonderry
Steelwork, approvals and making good for rear extension steels in Derry/Londonderry and nearby.
- Survey, design and installation in one
- Covering BT47, BT48
- 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
About our rear extension steels service in Derry/Londonderry
Rear extension steels in Derry/Londonderry are planned around the house, not a standard kit. We also cover the surrounding towns and villages in Derry City and Strabane. We visit, measure and check what the wall carries, then arrange calculations and building control approval before any steel is ordered.
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
- 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.
- 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.
- 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.
- 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.
Four stages, one team
Survey in Derry/Londonderry
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
A full plans application or building notice goes to Derry City and Strabane District Council under the Building Regulations (Northern Ireland) 2012 before work begins.
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.
How much should I budget in Derry/Londonderry?
As a guide, budget £2,150–£6,000 including VAT for opening into a rear extension in Derry/Londonderry, 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 |
| Structural calculations for a beam | £220–£640 | Site measure or photos, beam and padstone design and calculations for building control |
Figures include our approximate regional adjustment for prices in Northern Ireland (-14%) and are rounded. How these figures are worked out.
Approvals in Derry/Londonderry
In Northern Ireland, structural work comes under the Building Regulations (Northern Ireland) 2012 and is approved by the local council's building control. For Derry/Londonderry that is Derry City and Strabane District Council. We submit a full plans application or building notice before work starts and book the inspections.
Northern Ireland has no Party Wall Act, so there is no statutory notice to serve. Where the steel bears into a shared wall, the title deeds and the general law apply, and agreeing the work with your neighbour in writing first is good practice.
Local questions answered
Do you cover Derry/Londonderry for rear extension steels?
Yes. We carry out rear extension steels in Derry/Londonderry and the BT47 and BT48 postcode districts. 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 Derry/Londonderry?
As a guide, budget £2,150–£6,000 including VAT for opening into a rear extension in Derry/Londonderry, 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.
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.