Removing an internal wall to open up a living space is one of the most common structural alterations carried out in UK housing. It is also one of the most frequently underestimated. This guide explains how load-bearing walls behave, what has to be considered when one is removed, and what a structural engineer will normally need and produce. It deliberately does not offer beam sizes or construction instructions, because those depend entirely on the loads and construction of the individual building.
What a load-bearing wall is
A load-bearing wall is any wall that carries load from the structure above and transfers it downwards to a supporting element or, ultimately, to the foundations. That load may come from floor joists bearing onto the wall, from a roof structure, from a wall on the storey above, or from a combination of all three.
A non-load-bearing wall, by contrast, carries only its own weight. It divides space, and can normally be removed without structural consequence — provided that assessment is correct.
Why appearance alone does not establish whether a wall is structural
It is a common assumption that a stud wall is non-structural and a masonry wall is structural. Neither is reliable. Timber stud walls are routinely used to support floors and roofs, particularly in loft conversions and in post-war construction, while some internal masonry walls carry nothing at all beyond their own weight.
Establishing the role of a wall requires evidence rather than inference. That usually means looking at the direction the floor joists span, what stands directly above the wall on the storey above, whether the wall continues through the floor construction, whether the wall is founded, and whether there is any sign that the roof structure is propped from it.
- Floor joist direction — a wall parallel to the joists may still carry a wall above, and a wall perpendicular to them almost certainly carries floor load
- Walls above — a wall on the storey above must be supported by something, and it is frequently the wall being considered for removal
- Roof structure — purlin struts and binders are often supported off internal walls that appear to be partitions
- Continuity to foundation level — a wall that stops at floor level is being carried by the floor below and changes the problem entirely
- Services and previous alterations — earlier work may have already modified the load path in ways that are not visible
Load paths
Structural design of an opening is fundamentally about re-establishing a load path. Removing a wall does not remove the load it was carrying; it simply requires that load to be collected and taken to new points of support.
The engineer will therefore carry out a load take-down: identifying every load arriving at the wall — floors, roof, walls above, and any imposed loading — and following that load from the new beam, through its bearings, into the supporting masonry or columns, and down to the foundations. A design that stops at the beam is incomplete, because it is very often the supporting construction below, not the beam itself, that governs.
Beam design
Where an opening is formed, the load is normally picked up by a beam. Steel is common in domestic alterations, but timber, flitch beams and reinforced concrete are all used where appropriate.
The beam is designed for bending, shear and deflection. Deflection frequently governs domestic beams, because excessive movement causes cracking to plaster, sticking doors and distress to any masonry supported above, even where the beam is comfortably strong enough. Where the beam is not restrained along its length, lateral-torsional buckling must also be considered.
Fire resistance, the connection of any secondary members, and how the beam will be encased and finished are all part of the design rather than afterthoughts.
Bearings and supporting construction
The point where the beam lands is one of the most common sources of problems on site. The bearing must be long enough, and the masonry or concrete beneath it must be able to carry a concentrated load that did not previously exist at that point.
This normally leads to a padstone or spreader designed to distribute the reaction, and sometimes to strengthening of the masonry below. Where the load is high or the existing masonry is poor, a column may be required instead.
Columns, where applicable
Where a beam cannot be supported directly on existing walls — for example where an opening extends the full width of a room, or where two beams meet — columns are used. A column introduces a highly concentrated load at a single point, which must then be carried by the structure and foundation beneath it.
Columns also affect the finished space, because they cannot generally be moved or trimmed on site to suit joinery. Their position is best resolved during design rather than during construction.
Foundations and the existing structure
Concentrating load at a small number of points frequently means that the existing foundation at those points is being asked to carry more than it was. Whether that matters depends on the ground conditions, the existing foundation type and depth, and the magnitude of the new load.
Trial holes are sometimes required to establish what is actually there. This is more often necessary in older properties, where foundations may be shallow, and in properties where earlier alterations have already redistributed load.
Temporary support
Before a load-bearing wall can be removed, the load it carries must be supported temporarily. Needling, propping and strongboys are all used, but the arrangement has to suit the loads, the construction and the sequence of work.
Temporary support is normally the contractor's responsibility, and it is a common cause of damage when it is treated casually. On larger openings, on multi-storey load paths, or where masonry above is in poor condition, a specific temporary works design is appropriate.
Construction sequencing
The order of operations matters. Padstones normally need to be installed and to gain strength before the beam is loaded. Beams are often installed before the wall below is fully removed. Where two openings are being formed on different levels, the sequence must ensure that the building is stable at every intermediate stage.
Sequencing questions are best raised before work starts. Once a wall is partially demolished, the options narrow considerably.
Building Regulations
Forming an opening in a load-bearing wall is notifiable building work. Building control will expect structural calculations demonstrating the adequacy of the new arrangement, and will normally inspect the beam and its bearings before they are concealed.
Other parts of the Regulations may also apply — for example fire protection to the beam, ventilation, and, where the wall separates dwellings, sound insulation and party wall considerations. The Party Wall etc. Act 1996 is a separate legal process from Building Regulations, and may apply where work affects a shared wall.
Information normally required
- Photographs of the wall, the rooms either side, the ceiling and any relevant external elevations
- Approximate dimensions: opening width, wall thickness, storey heights and room sizes
- The direction the floor joists span above and below, where known
- What is directly above the wall on the storey above, including any chimney breasts
- The age and construction of the property, and any known previous alterations
- Existing and proposed layout drawings, where they exist
- Any information about foundations, ground conditions or nearby trees
Typical structural engineer deliverables
- Structural calculations for the new beam, its bearings and any affected supporting construction
- A structural sketch or drawing showing the arrangement, sizes and key details
- Specification of padstones, columns and connections as required
- Comment on temporary support requirements and on sequencing where relevant
- Responses to building control and contractor queries during construction
Key considerations
- The beam is rarely the whole problem — bearings, supporting masonry and foundations frequently govern.
- Deflection, not strength, often controls the design of domestic beams.
- A wall's structural role must be established from evidence, not from its material or appearance.
- Temporary support and sequencing should be agreed before demolition begins.
- Forming an opening in a load-bearing wall is notifiable work and will require calculations.
Related BES tools and services
Related guidance
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Important limitations
This publication provides general information only and does not constitute structural engineering advice, design or assessment. Project-specific engineering requirements should be established by an appropriately qualified structural engineer.
BES-TG-002 · Version 1.0 · Reviewed August 2026 · Next scheduled review August 2027