Through-lounge knock-throughs · Cardiff
Through-lounge knock-throughs in Cardiff
Through-lounge knock-throughs across Cardiff, designed by a structural engineer and signed off by building control.
- Itemised written quote
- Beam sized by a structural engineer
- Covering Cardiff and nearby
- 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 Cardiff: how it works
Through-lounge knock-throughs join a front and back reception room into one long living space by removing the dividing wall and putting a steel beam in its place. It is most common in Victorian and Edwardian terraces, where the dividing wall usually carries the floor above and often meets the party wall close to the chimney breasts.
We carry out through-lounge knock-throughs throughout Cardiff, for homeowners, landlords and builders who need the structural part done properly. We cover the whole area, from the centre out to the suburbs. You get an itemised written quote that shows the calculations, approvals, steel, labour and finishing as separate lines.
What to expect
- The steel commonly needs fire protection to meet building regulations, usually by boxing it in fire-rated plasterboard and skimming it. In period rooms the box can be finished with a matching cornice so it reads as part of the original ceiling.
- 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.
- With the wall gone, the floorboards on each side may run in different directions or sit at slightly different heights. Matching reclaimed boards can be fitted across the old wall line, or the floor can be levelled for a new continuous finish.
- In most terraced houses the wall between the front and back rooms runs across the house and carries the floor above, plus the wall between the front and back bedrooms. It is normally load-bearing, but the engineer still checks before any design is drawn up.
- 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.
From survey to sign-off in Cardiff
Free visit
A short visit to Cardiff to see the job, agree what you want and check the bearings, floors and services that affect the design.
Calculations
The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.
Building control
We submit the application or notice to Cardiff Council under the Building Regulations as they apply in Wales, before work starts.
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 through-lounge knock-throughs cost in Cardiff?
As a guide, budget £2,300–£5,000 including VAT for through-lounge knock-through in Cardiff, based on published UK cost guides adjusted for prices in Wales (-9%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Through-lounge knock-through | £2,300–£5,000 | Wall between front and back reception rooms, steel beam, approvals, plastering and floor infill |
| Kitchen-diner knock-through | £2,300–£5,450 | Internal structural wall between kitchen and dining room, steel beam, approvals and making good (kitchen fitting extra) |
| Plastering and making good | £270–£1,090 | Boxing the beam, bead and skim, reveals, floor infill where the wall stood and tidy-up |
| Chimney breast removal (ground floor) | £1,350–£2,750 | Ground-floor breast removed, steel to support the breast above, building control and making good |
Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.
Building rules for Cardiff
Removing a load-bearing wall in Wales needs approval under the Welsh building regulations before work starts. For Cardiff the application goes to Cardiff Council or a registered building control approver, with the engineer's calculations, and a completion certificate follows the final inspection.
The Party Wall etc. Act 1996 applies in Wales as well as England, so a beam bearing into a shared wall needs a party structure notice at least two months before work starts. We arrange notices through a party wall surveyor.
More in Cardiff
Local questions answered
Can I stay at home while the work is done in Cardiff?
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.
Who approves through-lounge knock-throughs in Cardiff?
Structural work in Cardiff needs a building control application to Cardiff Council under the Welsh regulations, with a commencement notice before work starts. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.
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.
Should I keep the chimney breasts when knocking through?
Most people do, because the breasts frame the opening and support the stack above. Removing a chimney breast is a separate structural job needing its own design and approval, and it affects your neighbour if the stack is shared. Keeping them usually simplifies the steelwork and preserves the character of the room.
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.
Do I need consent to knock through in a listed building?
Yes, you need both listed building consent and building regulations approval. Listed building consent from the local planning authority covers internal structural changes to the building's fabric, and building control covers the structural safety. Carrying out works to a listed building without consent is an offence, so it must be in place before anything is booked.