BASEMENT CONVERSIONS & DIGS

Structural basement digs, conversions and extensions — fully project-managed from party wall agreement through to final finish. Serving North & East London, Essex and Hertfordshire.

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ADDING A WHOLE NEW STOREY, BELOW GROUND

Basements are some of the most technically demanding projects in construction — party wall agreements, underpinning, waterproofing and structural engineering all have to come together long before you see a finished surface. RJS Innovative Building project-manages the whole basement job from first structural survey through to final decoration, whether that’s a new-build basement dig under an existing home, a basement extension out under the garden, or converting an existing cellar into proper living space. Fully insured and fully project-managed — no job is too big or too complex for us to plan and deliver properly.

NEW BASEMENT DIGS

Full structural excavation beneath an existing property, underpinned and tanked to create a genuine new storey of usable space.

BASEMENT EXTENSIONS

Extending out beneath the garden to add a self-contained basement extension, connected back into the main house.

CELLAR CONVERSIONS

Converting an existing cellar or crawl space into a fully habitable, damp-proofed room.

WATERPROOFING & TANKING

Structural waterproofing to full British Standard tanking specification, so the finished space stays dry for good.

HOW WE RUN A BASEMENT PROJECT

01

Survey & party wall

Engineer’s survey, soil report and any party wall agreements sorted before design begins.

02

Design & itemised quote

Full structural design agreed with you, quoted section by section.

03

Excavation & structural works

Underpinning, excavation and tanking carried out to specification, project-managed throughout.

04

Fit-out & sign-off

First and second fix through to final finish, signed off together.

BASEMENT PROJECTS ACROSS NORTH & EAST LONDON, ESSEX AND HERTFORDSHIRE

We regularly carry out basement digs and conversions for clients in Woodford, Wanstead, Chingford, Ilford, Loughton, Chigwell and across Redbridge, Waltham Forest and Epping Forest — everywhere inside the A406, and further out into Essex and Hertfordshire. Wherever you’re based, get in touch to talk through your project.

READY TO START YOUR BASEMENT PROJECT?

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Working Hours

Mon-Fri: 8:30am – 7:00pm

Saturday: 9:00 – 5:00pm

Sunday: closed

Office

5 Chigwell Road, London, England, E18 1LR (non-postal address)

Serving North & East London, Essex & Hertfordshire

raphael.sappa@rjsinnovativebuilding.com

Get in touch

RJS Innovative Building Ltd © 2026. All rights reserved.

Company No. 10012712 | VAT No. GB 288 4229 64 | Registered office (non-postal): 5 Chigwell Road, London, E18 1LR