Builder's work in connection
The term ‘builder’s work in connection’ (BWIC) refers to builder's work that is necessary as a result of other works, typically mechanical and electrical services but also specialist installations, such as lifts, escalators, roller shutters, hoists and cleaning cradles, and so on.
For example, the installation of mechanical and electrical services might require:
- Cutting, forming or drilling through walls, floors or ceilings to allow services to pass.
- Ensuring structural integrity is not compromised.
- Chasing block and brickwork for conduits or pipes.
- Lifting and replacing floors.
- Asbestos removal.
- Plant moving services.
- Sealing holes.
- Reinstating fire, thermal or acoustic separation.
- Constructing plinths.
- Making good plaster and other finishes.
- Maintenance access requirements such as access panels, decking, platforms, cat ladders and handrails.
This may involve works that require building regulations approvals and possibly testing certificates (for example, cleaning cradle restraining bolts).
Builder's work in connection is generally carried out by the main contractor for a mechanical and electrical sub-contractor and other such specialist trades. However, sometimes, the mechanical and electrical works might be part of the main contract and the builders work in connection sub-contracted.
Builder’s work in connection should not be confused general site preliminaries such as; welfare provisions, site offices, plant, site waste clearance, and so on, which are priced separately.
Estimators typically price builder's work in connection as 7% of the specialist work value.
[edit] Related articles on Designing Buildings
Featured articles and news
Inspiring the next generation to fulfil an electrified future
Technical Manager at ECA on the importance of engagement between industry and education.
Repairing historic stone and slate roofs
The need for a code of practice and technical advice note.
Environmental compliance; a checklist for 2026
Legislative changes, policy shifts, phased rollouts, and compliance updates to be aware of.
UKCW London to tackle sector’s most pressing issues
AI and skills development, ecology and the environment, policy and planning and more.
Managing building safety risks
Across an existing residential portfolio; a client's perspective.
ECA support for Gate Safe’s Safe School Gates Campaign.
Core construction skills explained
Preparing for a career in construction.
Retrofitting for resilience with the Leicester Resilience Hub
Community-serving facilities, enhanced as support and essential services for climate-related disruptions.
Some of the articles relating to water, here to browse. Any missing?
Recognisable Gothic characters, designed to dramatically spout water away from buildings.
A case study and a warning to would-be developers
Creating four dwellings... after half a century of doing this job, why, oh why, is it so difficult?
Reform of the fire engineering profession
Fire Engineers Advisory Panel: Authoritative Statement, reactions and next steps.
Restoration and renewal of the Palace of Westminster
A complex project of cultural significance from full decant to EMI, opportunities and a potential a way forward.
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this.





















