A21 Building & Electrical Services is a Glasgow-based team of builders and electricians covering extensions, conversions, new builds and all trades — with jobs undertaken right across the UK.
From a single-room extension to a full new build, our in-house team and trusted trade partners cover every stage of the job.
Single & double-storey extensions designed and built to add space and value to your home.
Learn more →Loft, garage and basement conversions that turn unused space into rooms you'll actually use.
Learn more →Domestic and commercial electrical work, rewires, fault-finding and certification.
Learn more →Plumbers, joiners, plasterers and roofers — one point of contact for the whole job.
Learn more →We plan, schedule and manage every trade on site so you don't have to.
Learn more →A sample of extensions, conversions and electrical jobs completed around Glasgow. Full gallery and photos coming soon.
Single-storey rear extension with bi-fold doors, Bearsden.
Dormer loft conversion adding a bedroom & en-suite, Newton Mearns.
Complete rewire and consumer unit upgrade on a Victorian terrace, Shawlands.
"Sample testimonial — A21 were on time, tidy and the extension looks brilliant. Would use again."
"Sample testimonial — Rewired our whole house with no fuss, explained everything clearly."
"Sample testimonial — Managed the whole loft conversion project start to finish, great communication."
These are placeholder examples — replace with real customer reviews before launch.