Structural engineer in Lewisham

Structural engineering in Lewisham

Lewisham runs from Deptford (SE8) and New Cross (SE14) near the river, through Brockley (SE4) and Lewisham, Hither Green and Lee (SE13), to Catford and Bellingham (SE6) and Forest Hill and Honor Oak (SE23). It is a hilly borough of Victorian terraces and big villas, interwar cottage estates and riverside regeneration, and the housing changes noticeably from one hill to the next. We have worked on 13 projects in Lewisham since 2019.

Many of Lewisham's period houses have been divided into flats, and its slopes mean rear extensions often meet changes in level, retaining walls and steps between gardens. Those details, together with clay soils and mature trees, tend to drive the structural design more than the size of the extension itself. This page outlines what to expect across the borough and when it helps to involve an engineer.

Brockley terraces, Forest Hill villas and cottage estates

Brockley, Ladywell and Hither Green are known for Victorian terraces and pairs of villas, many with three floors including a lower ground level, many converted into flats. Forest Hill, Honor Oak and Sydenham have large late Victorian houses on steep streets. Deptford has older Georgian buildings and a great deal of post-war rebuilding.

Bellingham and Downham were built between the wars as cottage estates, with simple brick houses in short terraces and pairs, many now privately owned. Catford and Lee have Edwardian terraces and interwar semis. Shops with flats above line Lewisham High Street, Deptford High Street and Brockley Road.

Clay hills, river valleys and steep gardens

The hills of Brockley, Hilly Fields, Honor Oak and Forest Hill are largely London Clay, with slopes steep enough in places for retaining walls and slope stability to matter. Clay shrinkage from trees is a common cause of seasonal cracking across these areas. Toward Blackheath in the east, pebbly sands and gravels cap the higher ground.

The Ravensbourne and Quaggy rivers run through the borough and meet in Lewisham town centre, with alluvium and gravels along their valleys and some land in flood zones. Deptford and New Cross near the Thames have softer alluvium and made ground. For hillside gardens, a slope stability assessment is worth considering before cutting into the bank.

Structural projects common in Lewisham

Side return and rear extensions on Brockley and Hither Green terraces, loft conversions, conversions of large houses into flats and alterations to cottage estate houses are typical here. Sloping sites add retaining walls and stepped foundations to otherwise simple projects.

• Side return extensions on Victorian terraces
• Lofts and dormers on cottage estate houses
• Retaining walls on Forest Hill slopes
• Conversions of large villas into flats
• Stepped foundations on sloping plots
• Crack and movement investigations on clay

Lewisham Council, conservation areas and flood zones

Lewisham has conservation areas including Brockley, Ladywell, Deptford High Street and parts of Forest Hill and Blackheath, and some have Article 4 directions affecting windows, roofs and front gardens. Lewisham Council can confirm what applies to your property. Near the Ravensbourne and Quaggy, a planning application may have to deal with flood risk.

Splitting a large Lewisham house into flats brings fire separation, sound insulation and extra loads, which our guide to house-to-flat conversions explains. Building a rear extension against a boundary also means serving notices on the neighbours.