Basement & cellar steels · London
Basement & cellar steels in London
Basement & cellar steels across London, designed by a structural engineer and signed off by building control.
- Price fixed in writing once scope is agreed
- Building control arranged
- Temporary works and making good included
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
Planning basement & cellar steels in London
Basement and cellar steels are the beams and columns that hold up the house above when walls are removed, openings are formed or new space is dug out below ground level. They carry the ground floor and walls down to new foundations, and are installed in a sequence set out by a structural engineer, alongside underpinning, excavation and waterproofing.
Looking for basement & cellar steels in London? Towns we cover include Bexley, Barking and Enfield Town, 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.
Worth knowing before you start
- Basements can stay damp even with waterproofing in place, so steel used below ground is protected against corrosion as the engineer specifies. That might mean an upgraded paint system or galvanising, particularly where steel sits close to external walls.
- Basement steel frames often rely on columns because there is nowhere else to land the load. Each column sits on its own foundation or a thickened part of the slab, and its position needs agreeing early so it does not end up in the middle of a room.
- In terraced and semi-detached homes, basement work nearly always affects shared walls. Excavating near a neighbour's foundations and underpinning a party wall are both notifiable under the Party Wall etc. Act 1996 in England and Wales.
- Below-ground rooms need a waterproofing design, often a cavity drain membrane, a tanking system or both. Column bases and beam bearings that pass through the waterproofing are detailed so they do not become a route for water.
- Basement projects run for weeks rather than days, and the steel goes in at set points during the dig. Noise, spoil removal and deliveries peak during excavation, and with careful planning the house above can often stay occupied.
Four stages, one team
Survey in London
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 basement & cellar steels cost in London?
As a guide, budget £3,200–£8,300 including VAT for basement or cellar steelwork in London, based on published UK cost guides adjusted for London prices (+28%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Basement or cellar steelwork | £3,200–£8,300 | Beams and columns with pad foundations under the floor above (excavation and waterproofing extra) |
| Party wall surveyor (agreed surveyor, per neighbour) | £1,150–£2,550 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) |
| Building control fees | £320–£830 | Building notice or full plans fee and inspections; varies by council or approver |
| Fire protection to a steel beam | £190–£770 per beam | Fire-rated board boxing or an intumescent coating system as specified |
Figures include our approximate regional adjustment for London prices (+28%) and are rounded. How these figures are worked out.
Building control and neighbours in London
Structural openings in English homes need building regulations approval before work starts. The local council's building control team can deal with it, or you can use a registered building control approver. Either way the steel is inspected before it is covered, and a completion certificate is issued at the end. Keep it safe for when you sell.
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.
Basement & cellar steels by town
- Brent
- Islington
- Westminster
- Bexley
- Barking
- Archway
- Sutton
- Croydon
- Ilford
- Enfield Town
- Harrow
- Tottenham
- Walthamstow
- Dagenham
- Becontree
- Romford
- Hayes
- Wembley
- Fulham
- Edmonton
- Southall
- Putney
- Battersea
- Purley
- Peckham
- Chingford
- Uxbridge
- Wimbledon
- Stamford Hill
- Brixton
- Hounslow
- Finchley
- Cricklewood
- Mitcham
- Feltham
- Acton
- Beckenham
- Chelsea
- Streatham
- South Croydon
Basement & cellar steels in London: your questions
Who approves basement & cellar steels in London?
Structural work in London needs a building notice or full plans application to the local council's building control team or a registered building control approver. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.
Can I stay at home while the work is done in London?
Usually, yes. The work area is screened and floors are protected. The rooms either side of the opening are out of action for a few days, and there is some noise and dust while the masonry comes out.
Do I need a party wall notice for basement work?
In England and Wales usually yes, if you are excavating near a neighbour's foundations within the distances the Party Wall etc. Act 1996 sets, or underpinning a shared wall. Notice periods apply before that work starts. We arrange a party wall surveyor to handle the notices, though we do not give legal advice.
Do I need steel beams for a cellar conversion?
Often, yes. If any cellar walls are being removed or opened up, or the ground floor above is being altered for a stair or lightwell, steel beams and columns are usually needed to carry the house above. A structural engineer looks at the layout and loads and specifies the steelwork.
What paperwork will I get for basement steelwork?
You should end up with the engineer's calculations and drawings, the building control completion certificate, the waterproofing details and, where it applied, the party wall paperwork. Keep them together, as surveyors and solicitors usually ask for them when the property is sold or remortgaged.
Will columns be needed in my basement?
Quite often. Below ground there may be no suitable wall to support the end of a beam, so a column carries the load down to a foundation. The position can usually be agreed with you at design stage so the column sits within a wall line, a kitchen island or a storage area.
What happens at the survey visit in London?
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.