Vertical Extension and Cantilevered Staircase at Cowcross St, London

Stoneforce commissioned the LSJ Engineering team to build a vertical extension in Cowcross Street, London, in 2018. We fitted a cantilevered staircase on the same job.

  • Client: Stoneforce
  • Structural detail by: Mark Ebbs
  • Job Duration: September 2018-January 2020

This was another vertical extension, at Cowcross Street in Farringdon, central London.

We supplied and erected a two story extension, on top of a building already three stories high. The building needed its roof removed to complete the works, so the main contractor put a full scaffold lid on it. This made erecting our frame with a mobile crane very difficult! Thankfully, we were provided with a hoist to get all the steel sections to roof level. We erected the frame using Genie lifts and gantry frames for the heavier sections.

On the same contract, we supplied and fitted an unusual cantilevered staircase from the basement level to ground floor. The stair flight formed continuous 20mm steel plate treads and risers, with non-slip nosing strip slots milled into the treads. The whole stair cantilevered off a concrete wall. To hide the fixing points, a stud wall was built a few inches in front of it, and the treads and risers fully welded together. Because some welding and grinding were involved in the fitting process, the stair was painted on-site.

What do you think of the finished work?

Note: you can click on the images to enlarge them.

Interested in commissioning steel work from LSJ Engineering?

We are open for commercial steel work! If you like the look of our work, we’d love to hear from you. Get in touch here or email You can also phone us on 01702 290 585. Find write ups of our other staircase projects here, and our structural steel work projects (including more vertical extensions!) here. We look forward to hearing from you.

Published by LSJ Engineering

LSJ Engineering provides premium structural steel, architectural steel and staircases for businesses in Essex, London and the South East, from our base in Shoeburyness.

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