Open Plan Living in London: What's Involved in Knocking Through Walls

Creating open-plan living spaces by removing internal walls is one of the most common renovation commissions in London, and one of the most misunderstood. The idea — knock out a wall or two, get a bigger space — sounds simple. The reality involves structural engineering, building regulations, service rerouting, and a construction programme that needs to be managed carefully to avoid expensive problems.

This guide explains what actually happens when you open up a ground floor in a London terraced or semi-detached house, what the decisions are, and how to do it properly.

Is the wall load-bearing?

The first question is always the same: is the wall structural? In London's Victorian and Edwardian terraced housing stock, the answer is almost always yes — the internal walls run perpendicular to the street and carry the floor and roof loads above them. Removing them entirely requires a structural engineer's specification and a steel beam or reinforced concrete lintel to carry the loads the wall was taking.

A wall that is not load-bearing — a partition added at some point in the building's history — can in principle be removed more simply, without steel. But in practice, even non-structural walls often contain services (pipes, cables), and you cannot determine with certainty whether a wall is load-bearing from looking at it. This requires a structural engineer's assessment.

Do not trust a contractor who tells you a wall "looks fine to take out" without an engineer's involvement. Failed or inadequate structural support after wall removal is a serious and expensive problem, and it can take months to manifest as cracks, movement, or door frames that no longer close.

The structural solution

For a typical through-room in a Victorian terraced house — removing the wall between a front reception room and a rear kitchen — the structural solution typically involves one or more of the following:

A steel RSJ (rolled steel joist) spanning the opening, supported on padstones or steel columns at each end. The steel is specified by a structural engineer, who will calculate the required size based on the span and load. A typical single-span through-room in a two-storey Victorian terrace might require a 127x76 to 203x133 RSJ — but the only person who can determine this is the engineer.

Padstones — reinforced concrete or stone bearing plates — are installed at each end of the beam to distribute the load from the steel into the masonry below. These are load-critical elements that must be correctly specified and installed.

Temporary propping during the works. While the structural support is installed, the loads above need to be carried by temporary acrow props and spreader boards. This is a specialist operation — propping done incorrectly causes partial collapse, and in a connected terrace, the risks extend to neighbouring properties.

The steel installation sequence is typically:

1. 1.Temporary propping installed to carry loads above the wall
2. 2.Wall demolished in sections, working away from the ends
3. 3.Padstones formed at bearing positions
4. 4.Steel lifted and positioned (often requiring specialist lifting equipment in tight London terrace conditions)
5. 5.Steel made good to the ceiling level — either boxed in or expressed, depending on the design
6. 6.Temporary propping removed once the steel is fully bearing

This is not a DIY operation, and in a terraced house with party wall considerations, it needs to be carefully planned.

What else is in the wall?

The structural question is the biggest, but it is not the only one. Most internal walls in Victorian and Edwardian properties also contain:

Electrical cables. Circuit routes typically run through wall cavities. When a wall comes down, these circuits need to be identified, safely isolated, rerouted, and reconnected by a qualified electrician. This is a building regulations requirement — new electrical work must be notified and inspected.

Gas and water pipes. Less common in internal walls, but not unusual — especially where a kitchen or bathroom adjoins the space. Any services in the wall need to be identified before demolition starts.

Chimney breasts. Many Victorian rooms have chimney breasts projecting from the walls. If the wall to be removed incorporates or adjoins a chimney breast, the structural implications are more complex — the chimney stack above needs to continue to be supported, which often requires a separate support structure.

A proper pre-demolition survey should identify all of these. Your structural engineer and M&E consultant (or an experienced main contractor) should produce a plan for handling services before any wall comes down.

Planning and building regulations

Does removing a wall need planning permission?

In most cases, no. Removing an internal wall in a residential property is not a change of the external appearance and does not require planning permission. Exceptions apply to:

• —Listed buildings — any structural alteration, including internal wall removal, requires listed building consent
• —Permitted development conditions — some properties have conditions attached to their planning permission that restrict internal alterations (unusual but worth checking)

Do you need building regulations approval?

Yes, in virtually all cases where structural work is involved. Building regulations cover:

• —The structural adequacy of the new configuration
• —The fire safety implications — removing a wall often affects compartmentalisation and escape routes
• —The electrical work involved in rerouting services

A Full Plans application is the appropriate route for this type of work. Building control will inspect the structural works and, once satisfied, issue a completion certificate. This is a document you will need when you sell the property.

For more on the distinction between planning permission and building regulations, see our full guide to building regulations vs planning permission.

Party wall implications

If your property is a terraced or semi-detached house, structural work near the party wall (the shared wall with your neighbour) may trigger the Party Wall etc. Act 1996. This applies when:

• —Notifiable works are carried out to the party wall itself
• —Excavation occurs within 3 or 6 metres of the neighbouring structure (relevant for accompanying underpinning)
• —A new wall is built at or astride the boundary

Removing an internal wall that does not adjoin the party wall typically does not trigger the Act. But if the works involve any underpinning, excavation, or structural alterations to the party wall, notices will be required. See our Party Wall Act guide for the full process.

Designing the new space

Opening up a ground floor creates an opportunity that needs to be designed carefully. The questions are:

How does light work in the new space? Victorian terraces have front-facing and rear-facing rooms, separated by a wall and a staircase. Removing the wall creates a longer space, but may produce a dark middle section if natural light from the front and rear cannot reach it. Roof lights, over-door glazing, and careful specification of internal surfaces are all tools for addressing this.

Where does the kitchen go? In a knocked-through ground floor, the kitchen is typically placed at the rear — closest to the garden, with a direct connection to outdoor space if there is a rear extension or bifold doors. The dining area bridges kitchen and living, and the front room becomes a more formal sitting area. This layout suits most Victorian terrace plans well.

What happens to the staircase? The staircase typically runs alongside the through room. If the staircase wall is being removed as part of the opening, the structural implications extend to the staircase itself, and the redesign needs to include how the staircase reads within the new open space.

How are the services — heating, ventilation, electrical — distributed in the new layout? A knocked-through kitchen-diner-living space needs heating provisions throughout, ventilation for the cooking zone, and electrical provisions designed for the new layout, not adapted from the original room configurations.

These are all design decisions that are much better made before work starts than resolved on site.

If you are planning to open up your ground floor and want advice on what is involved and what it is likely to cost, contact us to arrange a site visit. You can also see examples of our extension and renovation projects in our portfolio.