Structural Carpentry Across Berkshire and South Buckinghamshire

Structural carpentry is the carpentry that holds a house up, rather than the carpentry you notice once it is decorated. It covers four areas: floor joists and timber floor structures, stud walls and timber partitions, trimmers and noggins around stair openings, and the replacement of rotten or damaged structural timber. All four share the same discipline — the work has to be sized and specified correctly before a saw is picked up, because a wrong decision here is a safety issue, not a cosmetic one.

We treat that discipline as non-negotiable. Spans, joist sizes and spacing are calculated per TRADA span tables (or equivalent) for the specific timber grade and loading involved — they vary by species, grade, spacing and load in ways that make one job a poor guide to the next, even in houses built in the same street in the same decade. Structural alterations — removing or altering a load-bearing wall, forming a new opening, strengthening an undersized floor — need a structural engineer’s calculation and, in almost every case, Building Regulations sign-off before work starts. We build to that specification; we do not calculate loads or design structural solutions ourselves.

Floor Joists & Timber Floor Structures

Timber floor structures come to us in two states: new, where a floor is being formed for an extension or a loft conversion, and failing, where existing joists have begun to sag, bounce underfoot, or were never adequate for a new load — a bathroom added above a room that was not built to carry one, or a loft floor being converted into habitable space. Either way, joist size, spacing and span are confirmed against the published span tables for the exact grade specified, or against a structural engineer’s calculation where the load is unusual or the span is long. Sistering an existing joist, fitting joist hangers, noggining at the specified centres, and decking are all carried out once that specification exists — not before. See our floor joists & timber floor structures page for the fuller picture on diagnosis, sistering and replacement.

Stud Walls & Timber Partitions

Most stud walls we build are straightforward partitions — splitting a room, forming an en suite, closing off a landing — and the carpentry there is about setting out square, plumb, and noggined at the right centres for whatever fixes to the wall later. A stud wall that actually carries load — supporting a floor or roof above, or standing where removing it would need a new beam — is a different job. Whether a wall is load-bearing, and what has to replace it if it is altered or removed, is a structural engineer’s assessment, not something we judge by eye on site. We frame to the engineer’s drawing; we do not take the decision on whether a wall can be safely altered. See our stud walls & timber partitions page for more on new partitions versus load-bearing alterations.

Trimmers, Noggins & Stair Openings

Forming an opening in a timber floor — for a stairwell, a loft hatch, or around a chimney breast — means cutting through joists that were carrying load continuously, and replacing that continuity with trimmer joists around the opening. Trimmers carry the load of every joist they interrupt, so they are typically doubled or tripled timbers, hung on proper joist hangers rather than simply nailed through, and sized to the specification for the opening in question. Stair openings bring their own requirement: Building Regulations Part K governs stair rise, going and headroom, and we build the opening to the dimensions set out on the stair supplier’s or architect’s drawing rather than estimate clearance ourselves. We coordinate trimmer position directly with whoever is supplying the staircase, so the two pieces of work meet correctly. See our trimmers, noggins & stair openings page for the full detail.

Rotten & Structural Timber Replacement

Rot in a structural timber rarely announces itself where the damage actually is — a spongy floor near an external wall, a door frame that has swollen and split, a joist end that has lost its bearing under a leaking gutter. Before anything is replaced we establish how far the rot actually extends, since it is almost always further than the visible damage suggests. The affected section is then cut back to sound timber and either spliced with a matching section or replaced with a complete new structural member, sized to match the original or to an engineer’s specification where the repair needs to carry more load than before. We also flag the underlying moisture source — a failed seal, a blocked gutter, rising damp — because replacing timber without fixing what caused the rot is only a temporary repair. See our rotten & structural timber repairs page for how we assess and carry out this work.

Structural carpentry rarely stands alone on site — it is usually part of a wider first fix stage alongside timber framing and door linings, and the same discipline applies to the structural timber in a door frame as it does to a floor joist. See our first fix carpentry page for how the two connect, or our burglary damage repairs page where a door frame has split from a forced entry rather than rot.