Steel BeamInstallers
Garage conversion with the old door opening being bricked up around a new window

Garage conversion openings · Mitcham

Garage conversion openings in Mitcham

Garage conversion openings for homes in CR4, SM1, SM4, designed by a structural engineer.

  • Price fixed in writing once scope is agreed
  • Building control arranged
  • Temporary works and making good included

Free survey in Mitcham

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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

About our garage conversion openings service in Mitcham

Planning garage conversion openings in Mitcham? Our team covers CR4, SM1, SM4, SM5 and SW16 and the streets around them. We also cover the surrounding towns and villages in London. You get one written quote for the calculations, approvals, propping, steel and making good.

For integral garages with a bedroom above, the beam over the garage door matters even more, because it carries the front wall of the room upstairs. We arrange the survey visit, engineer's calculations, building control, propping, any steel and making good, with the structural items set out in one itemised written quote.

Worth knowing before you start

  • Garages built before 2000 can contain asbestos cement in roof sheets, wall panels or the garage door itself. A survey of the materials being disturbed is needed before work starts, so any asbestos can be removed or managed correctly.
  • The structural part of a garage conversion, covering the infill foundation, the wall and any new opening, typically takes one to two weeks. The full conversion with insulation, electrics, plastering and flooring takes longer, depending on the scope.
  • The price depends on whether the garage door beam needs replacing, the foundation needed for the infill, whether a new opening is formed into the house, the brick or cladding finish, and any fire separation work that has to be kept or added.
  • Most garage conversions do not need planning permission, but some estates have conditions removing permitted development rights for garages, and listed buildings or flats need consent. Changing the front elevation can also need permission in some areas.
  • Once the garage becomes a habitable room, the energy efficiency requirements of the building regulations apply. Walls, floor and roof normally need insulating to current standards, so the structural design and the thermal upgrade are planned together.

Four stages, one team

  1. Free visit

    A short visit to Mitcham to see the job, agree what you want and check the bearings, floors and services that affect the design.

  2. Calculations

    The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.

  3. 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.

  4. 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.

What do garage conversion openings cost in Mitcham?

As a guide, budget £1,300–£3,850 including VAT for garage door opening infill (structural part) in Mitcham, based on published UK cost guides adjusted for London prices (+28%).

JobTypical guide rangeWhat it usually covers
Garage door opening infill (structural part)£1,300–£3,850Beam or lintel checked or replaced, foundation and infill wall for the old door opening (window and finishes extra)
Widening an internal doorway£1,300–£3,200Opening widened with a new lintel or short beam, approval where structural, and making good
Steel beam replacement£2,550–£7,050Propping, removing the failed beam, new steel on proper bearings, approval and making good
RSJ supply and fit (single beam)£1,000–£3,200 per beamBeam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced separately)

Figures include our approximate regional adjustment for London prices (+28%) and are rounded. How these figures are worked out.

Building control and neighbours in Mitcham

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.

If the beam bears into a wall you share with a neighbour, the Party Wall etc. Act 1996 applies, and a party structure notice must be served at least two months before that work starts. We arrange this through a party wall surveyor.

Building rules in England

Garage conversion openings near Mitcham

Local questions answered

Do I need a party wall agreement for garage conversion openings in Mitcham?

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.

Do you also work near Mitcham?

Yes. We also cover nearby towns including Morden, Wimbledon, Streatham and Carshalton.

Does the infill wall need foundations?

Yes. A new masonry wall across the garage door opening needs a proper footing, as the existing garage slab is usually not designed to carry it. A trench is dug across the opening and a foundation is formed to the engineer's and building control's requirements, then inspected before the wall is built.

How long do the structural works for a garage conversion take?

Typically one to two weeks for the structural stage: digging and concreting the infill foundation, building the infill wall, and forming any new opening into the house. Building control inspections fit around these stages, and the insulation, electrics, plastering and flooring of the conversion follow on afterwards.

Can I knock through from my garage into the kitchen?

Usually, yes. The wall between an attached or integral garage and the house is often load-bearing, so the opening needs a lintel or steel beam designed by a structural engineer and approved by building control. If any of the garage stays as storage, the opening needs fire separation, such as a fire door.

Can I stay at home while the work is done in Mitcham?

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.

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.