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Basement conversion with steel beams and a steel column on a concrete floor

Basement & cellar steels · Belfast

Basement & cellar steels in Belfast

Basement & cellar steels across Belfast, designed by a structural engineer and signed off by building control.

  • Itemised written quote
  • Beam sized by a structural engineer
  • Covering Belfast and nearby

Free survey in Belfast

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  • Free survey visit
  • Engineer's calculations arranged
  • Building control handled
  • Fixed written price once scope is agreed
  • England, Wales, mainland Scotland & NI

Basement & cellar steels in Belfast: how it works

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.

Basement & cellar steels in Belfast follows the same careful process wherever the property is: a survey, an engineer's design, the right approval and safe temporary works. We can survey in places such as Castlereagh and the villages around them. We price it all up front so there are no surprises once the wall is open.

Key points for your project

  • 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.
  • A basement room needs a safe way out in a fire, which affects the stair, the doors and sometimes an escape window into a lightwell. Steel in the basement ceiling also commonly needs fire protection to the standard building control asks for.
  • 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.
  • Victorian and Edwardian cellars often have shallow brick walls, vaulted coal stores extending under the front garden or pavement, and little or no damp protection. The engineer checks whether vaults and walls can stay and what new support they need.
  • Converting a cellar into a habitable room is building work needing building regulations approval, covering structure, fire escape, ventilation and damp protection. Digging out a new basement may also need planning permission, depending on the council and the scale of the work.

What happens, step by step

  1. 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.

  2. Design and price

    Calculations come back from the engineer and we confirm your fixed written price, line by line.

  3. Building control

    A full plans application or building notice goes to Belfast City Council under the Building Regulations (Northern Ireland) 2012 before work begins.

  4. 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 Belfast?

As a guide, budget £2,150–£5,600 including VAT for basement or cellar steelwork in Belfast, based on published UK cost guides adjusted for prices in Northern Ireland (-14%).

JobTypical guide rangeWhat it usually covers
Basement or cellar steelwork£2,150–£5,600Beams and columns with pad foundations under the floor above (excavation and waterproofing extra)
Steel column or post£430–£1,290 per columnColumn supplied and fitted with base and cap plates on a pad foundation
Fire protection to a steel beam£130–£520 per beamFire-rated board boxing or an intumescent coating system as specified

Figures include our approximate regional adjustment for prices in Northern Ireland (-14%) and are rounded. How these figures are worked out.

Building control and neighbours in Belfast

In Northern Ireland, structural work comes under the Building Regulations (Northern Ireland) 2012 and is approved by the local council's building control. For Belfast that is Belfast City 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.

Building rules in Northern Ireland

Basement & cellar steels by town

Questions about basement & cellar steels in Belfast

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.

How long does it take to fit steels in a basement?

Each stage of steelwork usually takes a few days, but it happens at several points through a basement project rather than all at once. The overall programme is set by the excavation, underpinning and waterproofing, and the steel is installed whenever the sequence reaches it.

How much headroom do I need for a basement conversion?

Enough for the finished room to be comfortable and for the stair to meet the building regulations headroom rules. Steel depth affects that, so the engineer may choose a shallower section or set beams within the floor above. Where headroom is too tight, lowering the floor with underpinning may be an option.

Do I need planning permission to convert a cellar?

Converting an existing cellar into living space usually does not need planning permission if the outside of the house is unchanged, though listed buildings need consent. Digging a new basement, extending under the garden or adding lightwells may need planning permission, and building regulations approval is needed either way.

Planning to take a wall out?

Book a free survey visit. You get an itemised written quote covering calculations, building control, steel and making good.