From the Technical Expert

Mold beneath vinyl


Telegraphing, bubbles and stains are what I see as the callback itch: painful, obvious and, in most cases, totally avoidable. I have spoken many times, over the years, about the necessity for good floor preparation. To stay in business and be profitable, our goal should be zero callbacks. There is no money to be made in fixing your callback situations. In addition, that reinstallation or repair time is irreplaceable. Those productive hours are gone forever and so are the profits.

Telegraphing is an image "transfer" to the surface of a condition existing below the vinyl. The following are some of the conditions that may cause telegraphing:

• Use of particle board

• Oriented strand board (OSB) is acceptable, but under smooth vinyl with little embossing, OSB may telegraph somewhat.

• Vinyl not sufficiently rolled

• Staples/nails not long enough

• Underlayment not being held down while installed to ensure contact

• Gun pressure too high

• No perimeter expansion joint

• Excessively cold materials including glue, underlayment and vinyl

• Incorrect stapling and nailing pattern

• Failure to sand underlayment joints

• Installation over wet patching

• Installation over existing embossed vinyl with no embossing leveler used (old pattern shows)

• Deflection or movement of subfloor causing underlayment joints to open

• Installing over broom finish concrete

• Installing over hot spots and pop-outs in concrete

• Failure to sand latex Portland cement patching and levelers

• Failure to remove drywall overspray

• Installing over framer's markings on the concrete

Incidents of vinyl staining have decreased substantially in the past few years. The fact that many of the stains from below generally indicated a mold/mildew issue created concerns. Many stains were not or are not of bacterial origin. Many are the result of improper adhesive being used, tracking from asphalt driveways and excessive heat.

The bacterial stains are the result of a moisture and food source. At one time, some gypsum patching compounds were known to provide the food source. These formulations have since been corrected.

In many instances, installing a new floor on top of the old was the choice of repair. Unfortunately, this is only a visual repair unless the source of moisture is curtailed. The most common sources of moisture are dishwashers, refrigerators, clothes washers and toilets. When the water source is removed, the mold will die. Returning to previously mentioned telegraphing, I would like to point out that there have been instances where trowel size was incorrect (too large) and consequently, with beads not being crushed out, became too hard, and with subsequent buffing became visible. In instances where this becomes an issue, a simple procedure is to lay a piece of 81/2-by-11-inch tablet paper over the beads and trace gently with a soft pencil. That way, spacing and bead height can be determined.

Another "itch" in regard to telegraphing and callbacks is when your underlayment or subfloor is not adequately fastened (for some of the reasons spelled out above) and squeaking develops from live load pressures after installation.

Contracting is a game, and money is how you keep score. So, do not get penalties, and run up the score.