Steel BeamInstallers
Victorian through-lounge with a boxed beam where the dividing wall used to be

Through-lounge knock-throughs · Mitcham

Through-lounge knock-throughs in Mitcham

Through-lounge knock-throughs 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

Through-lounge knock-throughs in Mitcham: how it works

Planning through-lounge knock-throughs in Mitcham? Our team covers CR4, SM1, SM4, SM5 and SW16 and the streets around them. The wider London area is covered as well. You get one written quote for the calculations, approvals, propping, steel and making good.

Many period terraces and semis were built with a front parlour and a back sitting room divided by a solid brick wall. Opening them into one through-lounge brings light from both ends of the house, but that wall commonly carries the floor joists, the wall between the bedrooms above and sometimes part of the roof load too.

Key points for your project

  • Ornate cornicing often runs around both rooms and stops at the wall being removed. Where practical, the run is extended across the opening by matching the profile, either run in place or cast, so the joined room looks original rather than patched.
  • Victorian brickwork is usually laid in soft lime mortar and the internal walls may be only one brick thick. The engineer allows for this when designing the bearings, and padstones are often used to spread the beam's load over the weaker masonry.
  • Chimney breasts on the party wall in each room often sit close to the dividing wall. The beam may need to bear near them or avoid them, so the engineer checks how the breasts and flues relate to the new bearing before the opening width is fixed.
  • If the house is listed, internal structural alterations need listed building consent as well as building regulations approval. Conservation area status does not usually affect internal work, but flats within converted period houses normally need the freeholder's consent.
  • Many owners leave short nibs of wall at each end of the opening rather than going fully wall to wall. Nibs can give the beam a bearing, line up with the chimney breasts and keep the feel of two linked rooms, but the engineer decides whether they are adequate.

From survey to sign-off in Mitcham

  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

    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. 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 Mitcham?

As a guide, budget £3,200–£7,050 including VAT for through-lounge knock-through in Mitcham, based on published UK cost guides adjusted for London prices (+28%).

JobTypical guide rangeWhat it usually covers
Through-lounge knock-through£3,200–£7,050Wall between front and back reception rooms, steel beam, approvals, plastering and floor infill
Kitchen-diner knock-through£3,200–£7,700Internal structural wall between kitchen and dining room, steel beam, approvals and making good (kitchen fitting extra)
Plastering and making good£380–£1,540Boxing the beam, bead and skim, reveals, floor infill where the wall stood and tidy-up
Temporary works and propping£190–£640Props, spreaders, needles and sole plates for a typical opening, installed and struck

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

Approvals in Mitcham

For Mitcham, building control is provided by the local council's building control team, or by a registered building control approver if preferred. We send them the engineer's calculations with a building notice or full plans application and book the inspections. Work done without approval can cause problems at sale and is far dearer to put right later.

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

Through-lounge knock-throughs near Mitcham

Local questions answered

How much do through-lounge knock-throughs cost in Mitcham?

As a guide, budget £3,200–£7,050 including VAT for through-lounge knock-through in Mitcham, based on published UK cost guides adjusted for London prices (+28%). 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.

What happens at the survey visit in Mitcham?

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.

What happens to the floor where the wall was?

A strip of exposed joists, or a footing in a solid floor, is left where the wall stood. Timber floors are patched with matching or reclaimed boards, and solid floors are filled and levelled. If you are fitting a new floor across both rooms, it is simply prepared level for the new finish.

Is the wall between two reception rooms load-bearing?

In most period terraces and semis it is, because it carries the floor joists and the wall between the bedrooms above. Some later houses have lighter partitions in this position, so the only way to be sure is an engineer's inspection. We arrange this during the survey and design stage.

Can I keep the cornicing when the wall comes down?

Usually yes. The existing cornice in each room is protected during the work, and a matching profile can be run or cast to bridge the opening once the beam is boxed and plastered. How closely it matches depends on the original design and its condition, which we check at the survey visit.

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.