Performance Standard:

The installation contractor must insure that concrete slabs, plywood, and OSB floors are clean, dry, smooth, flat and sound (i.e. free from structural defects) before installation of hard surface floor coverings.

Specifications:

Cleanliness Make sure no surface contamination remains which would interfere with proper adhesive bonding or the final appearance of the finish floor covering. This includes dirt, paint, sheet-rock mud, or any other foreign matter, either loose or stuck to the subfloor surface.

Dryness Subfloors should appear visually dry and have a normal color. Suspicious looking subfloors should be checked with a moisture meter to verify that moisture content does not exceed 14% for plywood/OSB surfaces, and does not exceed 4.5% for concrete surfaces.

Smoothness No subfloor surface irregularities remain which would likely interfere with proper adhesive bonding or the final appearance of the finished floor covering. This includes swollen or uneven panel joints, raised grain or wafers, ripples, waves, rough textures, and exposed aggregate concrete.

Flatness Subfloors must be checked for humps and dips with a 6′ straight edge. Any vertical deviation in the subfloor profile exceeding 3/16″ within a 6′ horizontal radius must be removed by grinding and/or using a cement-based leveling compound.

Soundness No subfloor sections are missing or otherwise unstable (i.e., loose, flexing, crumbling, soft, delaminated, flaking, peeling, cracked, or broken).

Standard Procedures:

Hand scrape or mechanically scour the subfloor surface to remove dirt, paint, sheet-roc,k mud, and all other foreign matter and substances.

Thoroughly sweep or vacuum the subfloor surfaces, and under baseboards.

Carefully inspect the subfloor condition and measure for flatness.

Re-nail occasional loose subfloor panels and countersink protruding nail heads.

Sand plywood or OSB joints.

Apply up to 15 pounds of a cement-based floor patch to skimcoat superficial surface rough spots, depressions, uneven joints, and other minor defects. Also, fill minor surface cracks, pits, and divots.

Place aluminum foil over suspicious surface contamination (vinyl installations only).

Fine sweep or vacuum the subfloor a final time to remove all small debris (vinyl installations).

Extra-Cost Procedures

When repair to a subfloor is necessary, it is considered out of the scope of normal floor preparation and incurs extra cost. The following are examples of extra cost procedures:

Skimcoating over 25% of subfloor surface;
Sanding the entire plywood or OSB panel surfaces;
Applying over 15 pounds of cement-based floor patch correct various subfloor defects;
Re-nailing all plywood or OSB subfloor panels;
Installing underlayment;
Grinding down concrete humps to flatten subfloor profile;
Grinding down or removing concrete overfill from earlier slab repairs;
Grinding down subfloor humps caused by Framing crowns or high joints;
Replacing sections of plywood or OSB subfloor panels, or installing support blocking from underneath;
Repairing or replacing missing portions of concrete slabs;
Leveling subfloors with self-leveling compounds