One hundred and eighteen firms, 71 limited companies and 11 sole traders. Specialisation weighted toward new builds (26), renovation (25), and extensions (22), with 19 firms in general building and 19 in project management. Fifteen belong to the GBTEA. The oldest, C.A. Duquemin, has been trading since 1924. —
Sixty-three builders on the island — mostly limited companies, weighted toward renovation (23) and new-build (21) work.
Fifteen practices — RIBA-chartered architects alongside MCIAT technologists — the oldest trading since 1980, the newest 2023.
Thirteen firms laying driveways and patios — asphalt contractors, block-paving specialists, and resin-bonded stone installers.
Nine firms handle site enabling — three trade as pure groundworkers, six fold drainage and footings into wider building trades.
Seven firms — structural formwork, pre-cast products, sprayed-concrete pools, road surfacing, driveways, and readymix delivery.
Five firms across five parishes — Paul Rouget (1996) to Guernsey Demolition Contractors (2024), plus asbestos, drilling and plant-hire.
Five extension builders — four limited companies and one sole trader, all five also working new-build or renovation lines.
Five firms handling construction programme delivery — the oldest PlanB (2005), the newest Concept 360 (2017).
Four firms — Timber Treatments (1979) anchors with BS8102 tanking and Delta Membrane accreditation; three based in Vale.
Four electrical contractors on the island — the oldest trading since 1985, three limited companies, two NICEIC-registered.
Three diamond-drilling and cutting specialists — The Drill Squad (2002), Ryan's (2019), and Diamond Drilling & Cutting Specialists.
One firm per niche, picked for editorial depth.
City & Guilds Qualified member of GBTEA; specialises in decking, roofing
RIBA Chartered Practice since 2003; architectural design, feasibility studies
Road contracting services for trade and public; ISO 9001 and 14001 certified
Building company; residential new builds, renovations, extensions, groundworks
Civil engineering contractor; reinforced concrete works, formwork, steel fixing
Specialist contractor for licensed asbestos removal across all Channel Islands
Building contractor with 50+ years' experience; commercial and residential
Building design, planning, project delivery; business consulting
Damp proofing & waterproofing; Certified Structural Waterproofing Surveyor
NICEIC Approved Contractor; electrical, solar PV, EV charger installations
Diamond drilling company; non-percussive techniques for concrete, stone, metal
Tagged in Building & Construction but not in one of the specific niches above.