Welder Capacity and Monday Turnover in an Occupied Clinic
An occupied medical office building needs 36,000 sf of heat-welded sheet vinyl and 6,000 lf of rubber wall base in 12 weeks. The owner will take turnover of six exam rooms every Monday beginning in week 2 and will not allow adhesive odor in open clinical areas during weekday hours. Your crew is five installers, but only one is certified to heat-weld seams; that welder averages 150 lf of seam per day. Each exam room is 400 sf and contains about 120 lf of welded seam; corridors total 8,000 sf with 1,800 lf of seam. The only freight elevator is reserved for flooring from 7:00 to 8:00 a.m. daily; after that, other trades have priority. Deliveries arrive weekly on Wednesdays. Sheet vinyl adhesive requires 24 hours before foot traffic, and the owner requires 48 hours of cure before patient use. The five-person crew can install 1,200 sf per day when material is staged on the floor. The general contractor has just moved completion up one week.
1. Calculate the installation and welding workload, and determine whether the crew and welder can meet the 11-week completion. What is the controlling constraint?
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Installation. 36,000 sf / 1,200 sf per day = 30 crew-days. Eleven weeks x 5 days = 55 working days, so the five installers have float on square footage alone.
Welding. Rooms = 28,000 sf / 400 sf = 70 rooms. Room seam = 70 x 120 lf = 8,400 lf. Add 1,800 lf of corridor seam = 10,200 lf. At 150 lf per day, one welder needs 68 working days, which exceeds the 55 available days. The welder is the controlling constraint, before elevator access and cure time.
Weekly turnover. Six rooms = 2,400 sf = 2 crew-days, but 720 lf of seam = 4.8 welder-days. One welder cannot complete six rooms plus corridors in a normal week. The schedule needs a second certified welder, planned overtime, or resequencing that begins welding as each room is finished. The 24-hour foot-traffic and 48-hour patient-cure rules also mean rooms must be installed by Wednesday and welded by Thursday for a Monday turnover.
2. Sequence the first four weeks to meet the Monday turnovers and protect clinical areas.
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Week 1: stage materials on the floor, protect corridors, complete a mock-up, and confirm HVAC and elevator access. Week 2: install six rooms Monday and Tuesday; weld Wednesday and Thursday; cure Friday through Sunday; complete base and detail. Corridors should be installed in weekend or night blocks to keep adhesive odor out of open clinical areas. With one welder, split the six rooms into early and late groups, but recognize the Monday turnover is at risk. A second welder should start in week 2.
Deliveries arrive Wednesday, so move rolls to the floor Thursday at 7:00 a.m., not Friday. Keep one empty room as a buffer for cure or punch work. Hold a daily huddle with the GC on elevator use, HVAC status, and room release. Do not let other trades store materials in rooms scheduled for adhesive that day.
3. The welder calls in sick for three days in week 4, and the GC refuses the cost of a second welder. What do you do?
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Do not use uncertified installers for heat welding. Reassign the crew to fitting, adhesive, base, and corridor preparation while the welder is out. Borrow a certified welder from another crew or subcontract the welding, and confirm certification and insurance before he starts. Notify the GC in writing the same day if a Monday turnover or completion date is at risk; provide a recovery plan and state the cost of the second welder against the cost of delay.
Use available float and targeted overtime before adding unapproved cost. If the GC still refuses, document the direction and preserve a time-impact claim under the contract notice provision. Do not substitute an unapproved seaming method or let an uncertified installer weld to save a day; that risks failed seams and warranty rejection.