Hardwood Floors April/May 2017

AT THE SITE

Starting from the Bottom (Continued)

• Existing glue-down floor: glue the new wood floor directly to the existing wood floor, running perpendicular or diagonal to the direction of the floor. If the thickness of the floor will allow, staple or nail the new floor to the existing floor. When installing new wood flooring parallel to an existing solid nail-down wood floor, add a minimum of 15/32” plywood underlayment over the existing floor to increase stability. • When installing new wood flooring at a 45-degree to 90-degree angle to the existing solid nail-down wood floor, additional underlayment may not be required. When installing over existing floors, including ceramic tile, terrazzo, marble, sheet vinyl, or cork tile, keep these things in mind: • Follow flooring and/or adhesive manufacturer instructions first and foremost. • New flooring installed over existing flooring will raise the floor elevation. This can pose issues with cabinets, appliances, exterior or interior doors, and stairs. • Be sure to check with local and federal Environmental Protection Agency (EPA) or Occupational Safety and Health Administration (OSHA) regulations for asbestos concerns. Violating these kinds of regulations can cost you tens of thousands of dollars in fines and expose you, your employees, and customers to the harmful effects of asbestos. • Glue-down parquet applications requiring Poly Vinyl Acetate (PVA) adhesives are not recommended over existing sheet vinyl, vinyl, or cork tile unless underlayment is put down first. Be sure to follow underlayment manufacturer recommendations if you choose to do this. • Other types of adhesives may require primer or vinyl blocker when installing over sheet vinyl, vinyl or cork tile flooring. Always follow adhesive manufacturer recommendations in these cases. • Nail-down applications over existing sheet vinyl or vinyl are acceptable when moisture from below is not a

concern, when fastener penetration is not significantly diminished, and when the subfloor meets all other requirements. Fasteners must penetrate into the subfloor by at least 5/8”. • When considering a glue down installation over ceramic tile, terrazzo, or marble check with the adhesive manufacturer for specific instructions. These floor coverings must be sound, secure and in-tact. They also must be flat to within tolerance (1/8” in 6’ or 3/16” in 10’). And finally, they must be properly prepared to receive adhesive, which may include scarification.

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