Reliable groundworks and structural building for homeowners, developers and architects across North London.
Hands-on in this trade since 2015, SJM handles everything from single-property extensions to full structural rebuilds — with direct contact with Sean throughout, not a call centre.
Comprehensive Construction Services
Extensions
Full domestic and commercial extension builds.
Demolition & Strip Outs
Safe demolition and complete internal strip outs.
Brickwork & Blockwork
Skilled brick and block laying with a clean finish.
Groundworks
Site preparation and groundworks for builds of every scale.
Drainage
Surface, foul and deep drainage systems installed to standard, including complex sites.
Foundations & Excavations
Precise, controlled excavation and engineered foundations — strip, raft, pile and ground beams to spec.
Concrete & Reinforced Slabs
Structural concrete and reinforced slabs poured to load.
Steel Erecting
Structural steel frame erection for residential and commercial builds.
Propping & Underpinning
Temporary structural support and propping solutions, plus structural underpinning to stabilise and strengthen.
Built On Trust And Capability
Over A Decade Of Hands-On Experience
Sean has been hands-on in the trade since 2015, and founded SJM in 2022 — experience you can see in the quality and detail of every project.
All Work Fully Insured
Public liability and employer's liability insurance as standard on every project.
No Job Too Complex
From domestic extensions to deep drainage and commercial foundations — we handle the difficult jobs others turn down.
Direct Contact With The Principal
You speak directly with Sean, the company director, from first enquiry to project completion.
Meet Sean
Sean grew up around the trade — his dad ran a construction business, and Sean joined him straight after leaving school, working hands-on for several years before founding SJM Building & Construction in 2022. He's been doing this work personally since 2015, and still oversees every project himself — from the first enquiry through to completion.
Recent Projects
Kensington Lower Ground Floor & Garden Structural Package
Full structural transformation of a Kensington LGF and garden. Heavy propping, foundations along with structural steel installation, underpinning, full drainage renewal and RC slab works throughout.
Cambridge New Build
A ground-up new build set in open grounds, complete with drainage, a wrap-around cantilevered patio overhanging a water feature, and installation of a natural swim pond.
Temple Fortune Basement & Pool
Large-scale basement dig-out with a reinforced concrete pool structure — RMD raking prop support, tied steel reinforcement, and staged concrete pours for the pool walls and slab.
Hampstead Strip-Out & Extension
Full property strip-out and extension, with structural propping throughout, demolition of the lower ground floor, and new structural steel installed. Drainage was renewed and extended, finished with a new beam and block floor.
Holly Croft Ave Steps & Retaining Wall Rebuild
Full demolition, a reduced dig and void former installation for tree root movement, then a reinforced concrete staircase and bases poured as one. Brickwork was rebuilt on top to replicate the original staircase, along with a new retaining wall, piers and landing.
Radlett Concrete Access Road
Full concrete access road installed for a unit yard — old tarmac broken out and replaced with a durable finished concrete surface.
Outdoor Seating Area, The Ox & Gate
Conversion of an unused outdoor area into a new seating space — the existing brick wall was demolished and rebuilt, with reinforced concrete poured to form the new base, levelled flush with the entrance for wheelchair access and finished with a railing surround.
Hendon Driveway Extension
Driveway extension and refresh with new herringbone block paving, an ACO drain channel, and a new brick wall.
Trusted By Homeowners And Developers
“A pleasure to see Sean and his team at work — their efficiency is second to none.”
Guy, Kensington
“We're delighted with our new home. The SJM team took all our worries and doubts on board, brought our dream to life — and we're over the moon with the swim pond!”
Rodger & Suzie, Cambridge
“Amazing job by Sean and his team — they got straight to work and installed the seating area. It turned out better than I could have imagined.”
Dez, Ox & Gate
Get A Free Quote
Tell us about your project and we'll get back to you within 24 hours.