Commercial Flooring: What Changes From Residential

Why this matters

A residential crew that is good at the work can lose money on its first commercial job without laying a single bad piece. The floor goes down well, and then the general contractor's superintendent asks for the moisture report that was never run, the architect rejects the wall base because it was not the submitted color, and the adhesive maker declines a warranty claim because the slab was never tested. Commercial flooring is the same trade with a paper trail attached, and most of what a residential shop has to learn is the paper, the sequence and the traffic.

The specification is the customer

On a house, the homeowner says what they want and the shop recommends how to do it. On a commercial job the decisions were made before you were called, in the project specification: a book of sections organized by CSI MasterFormat, with flooring mostly in Division 09 (tiling, resilient flooring, carpet and carpet tile, resinous flooring each under their own section numbers). The flooring section names the products, the adhesives, the substrate tests, the installation standard the work is judged against, the submittals, the attic stock and the warranty.

Three habits change:

• Read the whole section before bidding, including Part 1 (submittals, quality assurance, delivery and storage conditions, field conditions) and Part 3 (preparation and installation). Part 3 often names a substrate test method and an acceptance limit, or defers to the maker's, and that is a cost you carry.
• Substitutions go through the architect in writing. "Same thing, different brand" is a substitution request, not a field decision. An installed substitute that was never approved can be ordered out at your cost.
• Ask in writing. A question about the drawings is a Request for Information (RFI) through the general contractor (GC). A verbal answer from the superintendent is not a change to the documents.

Submittals come before material

Submittals are what you send for approval before ordering: product data sheets, color and pattern samples, the adhesive and its data sheet, a seam layout for sheet goods, maintenance instructions, the warranty form, and test reports the spec requires. Material is ordered after the approval comes back. The common failure is ordering on bid-day assumptions and submitting afterwards; when the architect picks a different wall-base color, the shop owns two pallets of the wrong one.

Track each submittal's status (sent, approved, approved as noted, revise and resubmit) in the job file. "Approved as noted" means read the notes; they often change a color or an accessory.

Moisture and pH reports are a deliverable, not a judgment call

On a house, a crew may meter a slab, look at the result and proceed. On a commercial slab the spec or the adhesive maker almost always demands a written test report before installation, by a named method. The shelf method is ASTM F2170 in-situ relative humidity or ASTM F1869 calcium chloride, with acceptance per the flooring and adhesive maker's limits; the procedure is in How to Run an In-Situ RH Test on a Slab and the background is in Slab Moisture Testing for Flooring. Two things change on a commercial job:

• Test count and conditions are prescribed. F2170 sets the number of probes by area, and both methods require the building to be at service conditions (enclosed, HVAC running) before and during testing. A test taken with the roof open answers nothing.
• Surface pH is commonly required too. ASTM F710, the practice for preparing concrete to receive resilient flooring, includes it, and the adhesive maker states the acceptable pH range.

The report goes to the GC. If a reading is over the maker's limit, the crew does not decide the fix. Mitigation, waiting and retesting, or changing products is an owner and architect decision, and the shop's job is to report it in writing and not install over it.

Materials a residential crew meets less often

Heat-welded sheet flooring. Healthcare, labs and food areas use sheet vinyl, linoleum or rubber with seams routed and filled with a melted weld rod so the floor is continuous and cleanable, often flash-coved up the wall over a fillet strip so there is no corner to hold dirt. The procedure is How to Heat Weld a Seam in Commercial Sheet Flooring.

Carpet tile. Laid in a pattern the spec names (monolithic, quarter-turn, ashlar or brick), usually over a pressure-sensitive release adhesive that holds tiles in place while letting a single tile come up for replacement. Arrows on the back show pile direction; the pattern decides whether they all point one way or rotate. Wrong adhesive or wrong open time and tiles slide under rolling chairs.

Rubber or vinyl wall base. Installed after the floor, before final paint touch-up. Outside corners are wrapped from one piece after scoring the back, inside corners are coped or mitered per the spec, and the toe sits tight to the floor. Coil base in long runs with few joints reads cleaner than 4 ft pieces.

Traffic a house never sees

Rolling loads. Pallet jacks, carts, hospital beds and rolling stools load a floor through a small wheel. Resilient makers publish rolling and static load limits, and the adhesive choice often changes for rolling-load areas (a permanent full-spread adhesive rather than a release adhesive). A floor rated for foot traffic under a supply cart dents, and the seams open.

Chair casters. Hard casters belong on carpet and soft (urethane) casters on hard surfaces. Office chairs on carpet tile with soft casters, or hard casters on vinyl, cause the wear and indentation complaints that come back at the shop. Chair mats are an owner decision, but the spec or the maker's maintenance data usually addresses them, and the crew can point it out at turnover.

Volume of foot traffic. Entry areas get walk-off carpet or entrance tiles to catch grit, and the maintenance program the maker publishes becomes part of the warranty.

The schedule belongs to the general contractor

Flooring on a commercial job usually goes in after ceilings and the first paint coat, before casework set on the floor, wall base and final paint, with the building enclosed and HVAC holding the conditions the maker requires. The GC's schedule decides the days; the trade decides whether conditions are acceptable. Occupied buildings add after-hours work: nights or weekends, with the space returned clean and usable by morning, which changes adhesive choice (fast-setting products), ventilation and how much can be opened in one shift.

The site is a construction workplace under 29 CFR 1926, and the GC runs site safety orientation, badging and its own rules. Grinding and cutting on concrete bring the silica standard; see related: Silica Dust in Flooring Work.

Worked example: one test report, two materials

A tenant fit-out for a 6,000 sq ft medical office on a slab on grade: 3,600 sq ft of carpet tile in offices, 1,900 sq ft of heat-welded sheet vinyl in exam rooms and the corridor, and 500 sq ft of luxury vinyl tile in a break room. 3,600 plus 1,900 plus 500 is 6,000.

Test count. F2170 calls for three tests in the first 1,000 sq ft and one more for each additional 1,000 sq ft, so 6,000 sq ft takes 3 plus 5, or 8 probes. The crew places them across all three areas, including the exam wing near an exterior wall, with the HVAC running at service conditions for the period the method requires.

The limits. Say the sheet vinyl adhesive maker's data sheet reads 85 percent RH maximum, and the carpet tile adhesive maker's reads 95 percent (illustrative values; read your own data sheets). The LVT adhesive in this example uses the same 85 percent as the sheet adhesive.

The readings. Six probes read between 78 and 84 percent. Two in the exam wing read 89 and 91 percent.

The call, area by area. The six probes are all at or under 85 percent, so every area they cover passes for every product. The exam wing is sheet vinyl at an 85 percent limit: 89 is 4 points over and 91 is 6 points over, so it fails. Had the same wing been carpet tile at 95 percent, both readings would pass with 6 and 4 points to spare. Same slab, same numbers, opposite answers, because acceptance belongs to the product going on top.

What the crew does. The report goes to the GC with all eight readings, the probe locations on a plan, test dates and conditions, and the two limits it was judged against, plus an RFI: the exam wing fails the sheet vinyl adhesive maker's limit; please advise. The offices and break room proceed on schedule. The exam wing waits for the owner and architect to choose among a maker-approved mitigation system, retesting after more drying time with HVAC running, or a product rated for the measured RH. Installing over 91 percent because the schedule is tight converts the GC's moisture problem into the flooring contractor's warranty problem.

What would change it. If the readings were taken with the building open and HVAC off, the whole report is invalid, passes included; the crew retests once conditions are at service levels. If the spec named F1869 calcium chloride instead of F2170, the result is an emission rate in pounds per 1,000 sq ft per 24 hours, not a percent RH, and the limit is the maker's for that method, not the RH number above.

What residential habits cost on a commercial floor

• Starting before the paper is back. Unapproved product, untested slab, no written direction. Each is defensible on a house and indefensible on a spec job.
• Fixing the GC's problem for free. Leveling a slab that is out of the specified flatness, patching a trench, or grinding someone else's overspray is extra work; get it directed in writing first. The flatness figures live in Floor Flatness Tolerances by Floor Type.
• Leaving no attic stock. The spec usually names extra material to be turned over at closeout, and it is easy to use it up on the job and discover the shortfall at the last inspection.
• Missing the closeout package. Maintenance data, warranty forms and attic stock receipts are often what releases retainage.

References

• CSI MasterFormat, Division 09 Finishes (the organization of the project specification)
• ASTM F2170 and ASTM F1869, concrete moisture test methods; ASTM F710, practice for preparing concrete to receive resilient flooring
• OSHA 29 CFR 1926, Safety and Health Regulations for Construction
• Flooring and adhesive manufacturers' installation instructions, load ratings and warranty terms
• See related: The Commercial Flooring Coordination SOP; How to Heat Weld a Seam in Commercial Sheet Flooring; Slab Moisture Testing for Flooring