BWIC Meaning in Construction (Builders Work in Connection)
BWIC stands for Builders Work In Connection. It covers the builder’s work needed to accommodate mechanical and electrical (M&E) services in a building: cutting holes, forming openings, chasing walls, building plinths for plant, providing fixings and making good afterwards. The main contractor normally carries out BWIC, and it is measured and priced as its own item in the bills of quantities. Key facts BWIC = Builders Work In Connection (with M&E services) Covers holes, chases, openings, plinths, fixings, sealing and making good Normally carried out by the main contractor, not the M&E subcontractor Measured under NRM2 work section 41 in UK bills of quantities Early cost plans often allow 1% to 5% of the M&E package value for BWIC What does BWIC mean in construction? BWIC is short for Builders Work In Connection, sometimes written out in full as “builder’s work in connection with mechanical and electrical services”. Every building needs holes for pipes, openings for ductwork, chases for cables and solid bases for plant. Adapting the building fabric like this is the builder’s job, not the M&E installer’s, and BWIC is the label the industry gives that work. You will meet the term in tender documents, bills of quantities, M&E specifications and on drawings1. In UK bills of quantities it has its own work section: NRM2 section 41, builder’s work in connection with mechanical, electrical and transportation installations. Under the older SMM7 rules the equivalent was section P31, holes, chases, covers and supports for services2. Watch out for wrong definitions floating about online. BWIC does not mean “best work in construction”, “built work in charge” or “by others”. If a UK construction document says BWIC, it means builders work in connection, full stop. The term comes from commercial contracting, but the same idea applies on a house extension or rewire. The electrician wants chases cut and the plumber wants holes through joists, and someone has to do that work and make good afterwards. On small domestic jobs it is often the same builder or the individual trades, but the work is still builders work in connection, whether or not anyone writes BWIC on a document. Construction drawings are full of abbreviations like this. If you have also spotted SVP on a plan, our guide to SVP meaning in construction explains that one. What are typical BWIC examples? BWIC covers dozens of small jobs, but they all follow the same pattern: adapt the building so the services fit, then put the finishes back. The table below lists the items you will see most often on a BWIC schedule. BWIC item What it involves Typical trade Holes and penetrations Cutting or forming holes through walls, floors and roofs for pipes, ducts and cables Builder / main contractor Openings Forming larger openings for ductwork, risers, grilles and access panels, with lintels where needed Main contractor Chases Cutting channels in blockwork, brick or plaster for cables and pipework Builder (M&E trade marks out) Plinths and bases Concrete bases for boilers, tanks, chillers, air handling units and switchgear Main contractor Fixings and supports Bearers, brackets, noggins and framing for equipment, cable tray and pipe runs Main contractor / carpenter Trenches and ducts Excavating and ducting for incoming gas, water, electricity and drainage Groundworker Sealing penetrations Sealing around pipes and cables where they pass through walls and floors, including fire-rated sealing on compartment lines Main contractor / firestopping specialist Making good Filling chases and patching plaster and finishes once services are installed and tested Plasterer / decorator Note making good at the bottom of that list. Once the electrician and plumber have finished, somebody has to fill the chases and patch the walls, and on most jobs that is a reliable local plasterer working behind the M&E trades. What are BWIC drawings? BWIC drawings, also called builders work drawings, tell the builder exactly what holes, openings, chases and plinths the M&E installation needs, with sizes, levels and setting-out dimensions. The M&E contractor or building services engineer produces them, usually one drawing per floor or per service. A good BWIC drawing uses a simple legend. Each symbol tells the builder the type of penetration, its size, and whether it needs fire-rated sealing afterwards. Ductwork, pipework and electrical containment are often shown in different colours so clashes stand out at a glance. Timing is everything. An opening formed in blockwork as the wall goes up costs little more than the lintel over it. The same opening diamond-drilled through a finished, decorated wall costs many times more and holds up two trades while it happens. BWIC drawings are meant to be issued and checked before each phase of the build, not after, so openings are formed rather than cut. On site the usual sequence is: the M&E contractor marks out from the BWIC drawings, the builder cuts or forms the work, the services go in, the penetrations are sealed, and the plasterer makes good. Miss a step and the snagging list grows fast. Who pays for BWIC? The client pays for BWIC in the end, through the main contract price. The practical question is where it is priced and who carries the risk if it gets missed. On a traditional contract, BWIC is measured in the bills of quantities under NRM2 section 41 and priced by the main contractor. Where the M&E design is not complete at tender stage, it often goes in as a provisional sum and is firmed up once the builders work drawings are issued. M&E subcontract packages vary. Some include the subcontractor’s own builder’s work, most exclude it and leave it with the main contractor. The subcontract documents should say which, in plain words. Disputes almost always come from gaps in that paperwork. The M&E subcontractor assumes the builder will cut and seal every hole. The builder has priced only what was shown at tender. Months later somebody has to pay for 200 unpriced penetrations. The fix is boring but simple: define BWIC clearly in the contract documents, state who cuts, who seals
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