Structural alterations cover more than knock throughs. Widening openings, removing chimney breasts, forming new doorways in external walls, and strengthening floors for a loft all fall into the same category, and all follow the same basic sequence.
Is the wall load bearing?
Clues include walls running at right angles to the floor joists, walls that sit directly above another wall on the floor below, and walls that support the ends of joists or a roof purlin. Solid masonry internal walls in older houses are often doing more work than they appear to.
The only reliable answer comes from lifting some floorboards and looking, and then having an engineer confirm it. Guessing from the sound a wall makes when tapped is not a method.
Engineer calculations and building regulations
For a load bearing wall, a structural engineer works out the loads coming down and specifies a beam, the bearings at each end and any padstones or new foundations needed under them. Those calculations go to building control, either the council or an approved inspector, before work starts.
Building control will usually inspect at key points, such as when the beam is in place before it is boxed in. At the end you receive a completion certificate, which matters when you sell the house.
- Structural calculations and beam specification
- Building control application
- Party wall notice if the work affects a shared wall
- Inspection before boxing in
- Completion certificate
How the work is done on the day
Temporary props and needles are installed above the wall to carry the load. Then the masonry is removed from the top down, bearings are prepared, and the steel or timber beam is lifted into place and packed tight. Only once it is carrying the load are the props removed.
Dust sheets and sealed doorways contain as much mess as possible, but removing a wall is dusty work. Plan to clear the rooms either side completely.
Making good after the structure is in
The beam is fire protected, usually with plasterboard, and the ceiling, walls and floor are patched where the old wall stood. Often the floor finishes on either side do not match in level or material, so a threshold or a new floor across both rooms needs planning in.
Services are the other thing to plan. Radiators, sockets and pipes that ran in the old wall need moving before it goes, not after.
Chimney breasts, openings and older buildings
Removing a chimney breast downstairs while leaving it upstairs needs proper support for the remaining masonry, and the neighbour's side of a shared stack must be considered. In older timber framed and listed buildings, alterations may need listed building consent and a lighter, more sympathetic approach.
With more than 40 years of carpentry and building behind us, we are used to working in older houses where nothing is quite square.
Questions to ask before you knock through
Ask what the finished room will be used for, whether the heating will cope with a bigger open space, and whether any pipes, cables or flues run in the wall. Check with neighbours if the wall is shared, and ask who holds the building control paperwork at the end. A clear answer to each of those avoids the surprises that usually push a knock through past its programme.
Getting a price
Every structural alteration is different, which is why we start with a free site visit. We look at what the wall carries, what sits in it and what will need making good, then provide a fixed-price written quote so the cost is settled before any demolition starts.
Common questions
Do I need planning permission to remove an internal wall?
Usually not for an internal wall in an ordinary house, but you will need building regulations approval if it is load bearing, and listed building consent if the property is listed.
Steel or timber beam?
It depends on the span and the load. The engineer specifies what is needed; steel is common for wider openings and heavier loads.
How long does it take to remove a wall?
The structural part is often done in a few days, but making good, plastering and drying add time before decoration.
Do you arrange the engineer?
We can work with your engineer or arrange calculations as part of the job, and handle building control inspections.