Internal structural alterations

Cutting an opening in a floor for a new staircase or a double-height space removes joists that were carrying load, so the joists either side have to pick up what the cut ones were doing. We design the trimmer and trimming joists around the opening, size them for the extra load and detail the joist hangers and connections. Where the opening is wide, the trimmer may become a steel or a doubled timber to keep deflection and bounce under control.

Changing a floor use, turning a loft store into a room, putting a heavy stone bathroom over a bedroom, or laying a screed on a timber floor, adds load the original floor may not have been designed for. We check the existing joists against the new imposed load, and where they fall short we design strengthening, sistering the joists, adding a mid-span beam, or replacing them. The point is that the floor is checked for its new job, not assumed to cope because it looks solid.

A refurbishment often involves several small structural changes at once, a new opening here, a moved wall there, a trimmed floor for a stair. Handling them as one coordinated package is cleaner than a scatter of separate calculations, because the load paths interact and Building Control can see the whole altered structure in one submission. We set out each element and how it connects to the next, so the builder has a single consistent set of information.

The calculations are prepared to the Eurocodes, the UK National Annex and Approved Document A, and issued with drawings the builder can price and build from. We coordinate with your architect or designer so the structure follows the layout you want and revise once if the plan moves. We serve homeowners, builders and developers across the UK, delivering calculations and drawings anywhere and arranging site visits by region where the existing structure needs to be seen.