The next step is to allow the floor and all underfloor construction to dry thoroughly. The process by which hardwood floors take on moisture and expand takes many weeks, unless water in liquid form has been in the picture. By the same token, its removal may also take several weeks, or even months. Once a program of drying has been set up, evidence that it is working can be seen within a short time. Its progress should be monitored by taking moisture readings on a bi-weekly or monthly basis, and no repairs should be attempted until the readings have remained balanced between face and back for 30 days to be sure that cupped floors have flattened as far as they are going to. (Floors with a surface finish react much more slowly to moisture changes.)

WHEN THE FLOOR RE-FLATTENS: If cupped floors flatten when they have dried, new considerations of a complete repair may arise:

Fastenings -- nail installation: The cupping action may have loosened nails to some extent. If so, this will express itself by squeaks or looseness when the floor is walked on. Face nailing or fastening from underneath with wood screws will correct the problem.

Adhesion -- mastic installation: Some types of wood floor mastic have re-tack properties which will allow the mastic to re-adhere even after the floor has been pulled loose and reset. If walking on the floor produces popping sounds, or the floor sounds "hollow" when tapped, adhesion has probably been lost. In this event the affected parts of the floor must be removed and replaced to accomplish an effective repair.

If an asphalt cut-back mastic was used originally, the dried-out floor can be removed and replaced (a few pieces at a time), as the mastic can be reactivated with a light spray of kerosene. Headless pins of hardened steel can be used also where mastic adhesion has been lost. These pins can be driven into either wood or concrete subfloors.

Once fastenings are secure, the floor can be filled where cracks exist, and either given a new coat of finish, after screening, or buffed with No. 00 steel wool, cleaned, and re-waxed. If the original finish was a surface type (i.e., Polyurethane), it can be re-coated only if it has not been waxed.

WHEN THE FLOOR REMAINS CUPPED after thoroughly drying it has most likely set new stresses and most boards will remain cupped indefinitely. In this case the only practical repair is a complete resanding and finishing job. Cracks should be filled as a normal part of the finishing process and fastenings checked and repaired before sanding.

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