Structural Engineering
in St John's Wood, NW8

Where a new or wider opening is formed in an existing external wall, the wall above must be supported, typically by one or two beams.

A steel beam should normally be protected against fire, most often with two or more layers of plasterboard.

Inside a villa, opening the ground floor rooms usually means a steel or timber beam carried on padstones, with temporary props while the wall is removed.

Source: Planning Portal: Extensions, Building Regulations: Structural Opening

Before a wall comes out, the floors and the wall above are held up on adjustable props, with steel needles through the brickwork where the load is heavy. The temporary works are designed with the permanent beam, so the sequence on site is agreed in advance.

Ceilings and cornices in the rooms around are protected, and props stand on spreader boards so they do not mark original floors.

A building owner proposing work covered by the Party Wall etc Act 1996 must give adjoining owners notice in the way the Act sets down.

GOV.UK says notice is needed before building on the boundary, working on a party wall or digging below and near a neighbour's foundations.

If the owners cannot agree, surveyors settle the work in writing; that agreement is separate from planning permission and building regulations.

Sources: GOV.UK: Party Wall etc. Act 1996 guidance, GOV.UK: Party walls and building work

Westminster's Policy 44 looks for listed buildings to keep their special interest, protecting original detail and historic fabric and restoring it where that is appropriate.

So in a listed villa we repair before we replace: a split joist is strengthened with a new timber bolted beside it, a decayed beam end is cut back and spliced, and a cracked arch is stitched rather than rebuilt. Where steel is unavoidable, it is hidden behind existing plaster, and the change goes to Westminster for listed building consent.

Source: Westminster City Plan 2019-2040 (2026, adopted January 2026)

Cracks in a St John's Wood house are often old and settled, but some come from tree roots, leaking drains or recent work next door. We record their width and pattern, fix tell-tales across the worst of them and read them over a period before deciding whether underpinning is needed at all.

Often the answer is to repair a drain or manage a tree and then stitch the brickwork, a much smaller job than new foundations.

Basements may encroach no more than 1.8 metres under the highway, with at least 900mm between the road surface and the vault.

Before skips or heavy equipment are placed, structures such as vaults beneath the pavement need careful consideration.

Many St John's Wood houses have coal vaults under the front path; we survey them before any heavy plant arrives.

Sources: Westminster City Plan 2019-2040 (2026, adopted January 2026), Westminster City Council: Code of Construction Practice (May 2026)

Westminster does not allow demolition, excavation or piling on Saturdays unless special permission has been granted.

Otherwise building work is allowed from 8am to 6pm on weekdays and 8am to 1pm on Saturdays.

We schedule breaking out and steel lifts for weekdays, and tell neighbours the days in advance.

Source: Westminster City Council: noise problems we can investigate