Structural calculations in Lewisham

Surveys for older and heritage buildings

Lewisham has 30 conservation areas, 57 Article 4 directions and 21 Heritage at Risk entries. The borough also contains 1 World Heritage Site.

The council's validation lists ask for a structural survey in two situations. For a listed or non-designated heritage building, the survey is Listed / heritage assets, and it describes condition, structural problems and repair options. For major schemes, the list reads Includes basements. That includes basements.

We prepare the measured drawings and the beam calculations for ordinary alterations. A heritage survey describing the condition of old fabric belongs to a suitably qualified professional, and we say so at the first call if your building needs one.

Houses and flats in a mixed borough

42.2 per cent of Lewisham households live in a house and 41.9 per cent own their home, so the borough splits fairly evenly between houses and flats. The houses tend to need a wide rear opening or a loft room. The flats need a wall or chimney breast taken out of a reception room.

In a flat the floor above may belong to someone else, so we trace the load path first and check the lease for landlord consent. Our loft conversion drawings in Lewisham show how a new floor and stair are drawn over the steel beneath.

Householder decisions in Lewisham

In its latest year Lewisham decided 578 householder applications, granted 89.4 per cent and decided 95.2 per cent in time. Its larger home extension prior approvals tell a different story, with 2 granted and 46 refused.

For structure, the timing is what counts. Permission comes first on schemes that need it, and the beam schedule can be prepared in parallel. Our planning drawings in Lewisham cover that stage.

A Lewisham calculation in four steps

We visit and measure the room and the wall, noting construction, thickness, what bears on it and what sits below. We then take the loads from the floors and roof above and size the beam for bending, shear and deflection. The padstones are checked against the brickwork beneath them. Finally the temporary support is specified for the builder, with the order of work.

The output is a numbered schedule that the examiner, the builder and a future buyer's solicitor can all read. If a wall turns out to hold a flue or a services run, we flag it at that point, before the builder prices the job on the wrong assumption. Where the building is old, we also say which parts of the calculation rest on an assumption, such as the thickness of a wall we could not open up, so the inspector knows what to confirm on site.

What we charge and what you get

The fee starts at £295 including VAT, fixed after a constraints check. You receive the calculations, a beam and padstone schedule and a marked-up layout about a week after the survey. A second technologist checks the set before it leaves us, and we revise it at no charge if building control asks.

The sizes feed our building regulations drawings in Lewisham. For the wider service see architectural drawings in Lewisham, or compare the neighbouring rules in Bromley and Southwark.