Structural Alterations

What Are Structural Alterations?

Structural alterations involve modifying or removing load-bearing elements of a building — walls, floors, roof structures or foundations. The most common residential structural alteration is removing an internal load-bearing wall to create an open-plan living space, with a steel beam (RSJ — rolled steel joist) installed above to carry the load. Other common projects include chimney breast removal, widening door openings, raising or lowering floor levels, underpinning foundations, and creating new openings in external walls for windows or doors. Structural alterations are frequently carried out as part of a larger extension, renovation or loft conversion project, but can also be standalone works to modernise the layout of an existing home.

Structural Alteration Costs

Removing a single load-bearing wall and installing a steel beam typically costs between £2,500 and £6,000 depending on the span of the opening, the size and weight of the beam, and the finishing required. Longer spans or walls supporting upper floors may require larger beams with padstone foundations, increasing the cost. Chimney breast removal on a single floor costs £1,500 to £3,500, with additional cost if the stack above needs supporting steelwork. Creating a new opening in an external wall for a window or door — including lintel installation and making good — typically costs £1,500 to £4,000. Underpinning costs £1,000 to £3,000 per linear metre depending on depth and ground conditions.

Structural Engineering and Building Regulations

All structural alterations require calculations by a qualified structural engineer to specify the correct beam sizes, support details and construction method. The structural engineer produces drawings and specifications that the builder follows on site. Building regulations approval is required for all structural work — this ensures the alterations meet safety standards for load-bearing capacity, fire resistance and stability. A building control inspector will visit the site at key stages to check the work. MTD Building Contractors work with trusted structural engineers and manage the full regulatory process, including initial calculations, building control applications and inspections.

Common Structural Projects

The most requested structural alteration is removing the wall between a kitchen and dining room to create an open-plan kitchen-diner. This typically involves installing a steel beam (150mm to 250mm deep depending on span), supported by steel posts or padstones at each end, with temporary support (Acrow props) in place during the work. Other common projects include removing a chimney breast to free up floor space (the stack above must be supported or removed), lowering a floor to increase ceiling height in basements or older properties, and creating wider openings between rooms to improve flow and natural light.

How Long Do Structural Alterations Take?

A straightforward wall removal and beam installation takes 3–5 days including temporary support, demolition, beam installation, making good and plastering. More complex structural work — multiple openings, underpinning, or chimney removal across several floors — may take 1–3 weeks. If the structural alteration is part of a larger project such as an extension or renovation, it is integrated into the overall programme. We typically carry out structural work early in the project sequence so that other trades can follow without delay.