| A Class Windows Ltd | Sheerness | 2007 |
| A Class Zinc Roofing Ltd | Welling | 2025 |
| A Classic Improvements Limited | Great Yarmouth | 2024 |
| A Clyne Limited | Weymouth | 2008 |
| A Coakley Heating & Plumbing Ltd | Burscough | 2012 |
| A Cochrane Limited | Caldicot | 2009 |
| A Coffin UK Limited | Hayward'S Heath | 2019 |
| A Coldwell Tiling Limited | Rotherham | 2022 |
| A Colley Plumbing & Heating Limited | Plymouth | 2005 |
| A Colley Plumbing & Heating Services Ltd | Holmfirth | 2020 |
| A Collins Ltd | Aylsham | 2010 |
| A Collins Surveying and Estimating Ltd | Walsall | 2019 |
| A Complete Window and Door Service Ltd | Norwich | 2021 |
| A Connolly Commercial Limited | Wigan | 2017 |
| A Connolly Developments Limited | Wigan | 2017 |
| A Connors Electrical Ltd | Cardiff | 2022 |
| A Conroy Building & Development Ltd | Leigh-On-Sea | 2014 |
| A Construct Ltd | Dagenham | 2017 |
| A Construction Limited | St Agnes | 2017 |
| A Construction Professional Builds Limited | Rainham | 2022 |
| A Construction Services Limited | Birmingham | 1998 |
| A Contracts Ltd | London | 2018 |
| A Coombe Plumbing Contractors Ltd | Sutton-In-Ashfield | 2020 |
| A Cooper Complete Solutions Ltd | Leicester | 2014 |
| A Copeland Electrical Limited | Lancashire | 2007 |
| A Copeland Group Limited | Ashton-Under-Lyne | 1974 |
| A Cordery Limited | Hook | 2007 |
| A Cornick Contracting Ltd | Basingstoke | 2026 |
| A Couple of Decorators Ltd | Great Yarmouth | 2024 |
| A Courtney Electrical Services Ltd | Waterlooville | 2019 |
| A Cowen Groundworks Limited | Middlesbrough | 2017 |
| A Crabtree Electrical Limited | Bacup | 2009 |
| A Craftsman's Workshop Ltd | London | 2007 |
| A Cranmer Roofing Ltd | Purfleet | 2022 |
| A Crawford Electrical (Ace) Ltd | Wigton | 2018 |
| A Creighton Plant Hire Limited | Barnsley | 2013 |
| A Crombie Ltd | Banff | 2016 |
| A Cromie Limited | Newtownards | 2026 |
| A Cronshaw Ltd | Lancaster | 2026 |
| A Crosby Construction Limited | Durham | 2016 |
| A Crown Building Engineering Services Limited | Hornchurch | 2024 |
| A Crown Roofing Ltd | Croydon | 2025 |
| A Curnow & SON Construction Ltd | London | 2023 |
| A Curran Electrical Services Limited | Nottingham | 2016 |
| A Curtis Ltd | Romford | 2024 |
| A Custom Home Ltd | Plymouth | 2019 |
| A CUT Above Builders Ltd | Richmond Upon Thames | 2025 |
| A CUT Above Carpentry & Renovations Ltd | Snodland | 2020 |
| A D Adam & Sons Property Developement Ltd | Peterhead | 2019 |
| A D B Flooring Services Limited | Whitstable | 2009 |
| A D B Maintenance Service Ltd | Coventry | 2025 |
| A D B Plastering Ltd | Oxted | 2016 |
| A D Bacon Plastering Limited | Nottinghamshire | 2007 |
| A D Bleasdale & SON Ltd | Lancaster | 2007 |
| A D BLY Construction Limited | Hertfordshire | 2003 |
| A D Booth & Sons Cheshire Limited | Newcastle Under Lyme | 2021 |
| A D Booth & Sons Limited | Newcastle Under Lyme | 2004 |
| A D Brick Work Ltd | Harrow | 2020 |
| A D Bricklaying Limited | Derby | 2018 |
| A D Brickwork Contractors Limited | Basildon | 2025 |
| A D Brookes Electrical Services Limited | Redditch | 2021 |
| A D Build Limited | Halstead | 2023 |
| A D Builders Limited | Warks | 2003 |
| A D Building & Maintenance Services Ltd | London | 2020 |
| A D Building & Renovations Limited | London | 2025 |
| A D Building (Property) Services Ltd | Dereham | 2018 |
| A D C Builders Limited | Farnborough | 2013 |
| A D Carpentry & Building Limited | Ware | 2009 |
| A D Carpentry & Joinery Ltd | Swansea | 2019 |
| A D Carpentry Limited | Bournemouth | 2017 |
| A D Construction & Development Limited | Hassocks | 2014 |
| A D Construction UK Ltd | London | 2003 |
| A D Contracts (2026) Ltd | Belfast | 2025 |
| A D Contracts Limited | Leigh-On-Sea | 1998 |
| A D D Enterprises Limited | Yorkshire | 2000 |
| A D Dale Construction Ltd | Near Alsager | 2023 |
| A D Dhillon Construction Limited | Romford | 2016 |
| A D Electrical Contracting Ltd | Dereham | 2007 |
| A D Electrical NE Ltd | Middlesbrough | 2023 |
| A D Electrical Services (Midlands) Limited | Stafford | 2012 |
| A D Enterprise Heating & Plumbing Limited | Birmingham | 2019 |
| A D Environmental Limited | London | 2010 |
| A D F Building Contractors Limited | Scarborough | 2005 |
| A D Field Plumbing and Heating Ltd | Bude | 2015 |
| A D Finishes Limited | Shaftesbury | 2010 |
| A D Gillespie Limited | Clydebank | 2016 |
| A D Glassworks Limited | Chislehurst | 2015 |
| A D Grantham Limited | Doddington | 2016 |
| A D Green Building Ltd | Waterlooville | 2025 |
| A D H Developments Limited | Luton | 2021 |
| A D H Electrical (Essex) Limited | Billericay | 2008 |
| A D H Plumbing Ltd | Chatham | 2011 |
| A D H Services Limited | Benfleet | 2015 |
| A D Hawes Consultancy Ltd | Rochford | 2010 |
| A D Heating & Plumbing Ltd | Rayleigh | 2018 |
| A D Heating and GAS Ltd | High Wycombe | 2017 |
| A D Heating Limited | Turriff | 2008 |
| A D Hemmings Building Services Ltd | Hockley | 2016 |
| A D Hicks Carpentry and Building Limited | Braintree | 2017 |
| A D Home Improvements Limited | Wooler | 2003 |