The subfloor must be sufficiently dry before hardwood is installed. Moisture levels may be determined, as pictured, by using an electronic moisture meter with pin-probe attachment.

The ultimate durability of hardwood flooring definitely has been a contributing factor in the product's sales growth over the last two decades. The sweet reward associated with the closing of a sale can also turn extremely sour if it is followed by an inappropriate, weak installation. Product performance can and will be encumbered in the wake of a thoughtless installation.

A knowledgeable salesperson must determine the appropriate hardwood flooring product for the job site and be ready, willing and able to pass on -- not over -- the specification requirements for a long-lasting installation rather than merely opting for a quick sale. With the vast array of hardwood flooring products in today's market, a suitable option will be available. The consumer deserves the value that only an appropriately specified product can provide.

The hardwood flooring industry continues to explore and implement specifications and procedures for the potential control of the job site. Obviously, there are two completely different job sites for hardwood flooring installations. They are commercial and residential, and they include existing dwellings and new construction.

Unfavorable job site conditions are easier to detect in new construction. Existing structures, on the other hand, require that the contractor or installer perform a significant investigation on the history and structural integrity of the subfloor and surrounding environment. As with all installations, the relative humidity and moisture content of the subfloor constitute only the beginning of a complete job site analysis.

In addition to verifying that the moisture content and relative humidity fall within accepted parameters, the installer must note the grade and location of the subfloor in relation to the exterior ground level. To determine the grade of the subfloor, whether it is concrete or wood, physically inspect the outside perimeter of the structure and determine its point of contact with the slab and/or foundation. If any point of contact on the exterior is at a higher level than the subfloor on which the hardwood flooring is to be installed, engineered hardwood flooring is the only acceptable and recommended product for the situation.

The longevity of a hardwood installation could be placed at risk if all subfloor residues and contaminants are not removed from the subfloor.
Engineered floors can accommodate any grade classification, unlike solid-hardwood flooring which can only be installed on grade or suspended. For a solid wood on-grade installation, additional approved underlayment must be installed, according to industry standards, to provide the depth requirements for a moisture-protected nailing surface. This particular procedure, rather than an engineered wood installation, is a more common practice in the sun-belt region of North America.

That said, new construction will have its own hidden secrets. You'll need to determine when the basement concrete was poured. A good rule of thumb is that concrete curing requires a minimum of 60 days and as long as 90 days, depending on weather conditions and the average relative humidity during the curing period.

The weather patterns of various regions can come into play when it comes to concrete curing. Being a native of the Midwest, I can say with authority that the weather in my area can be unseasonable in any season. Weather extremes in my region are quite common, which can make even the most simple installation a challenge.

Other areas in new construction that need the flooring contractor's attention are the window panes that may have been broken during construction or by vandalism. Thresholds at all exterior doors should be placed and the installer should verify that no water has seeped into the interior of the home. Until the new home is under roof, subfloors maybe subjected to excessive moisture from torrential downpours. Although exterior grade moisture-resistant materials typically are used, delamination still can occur.

I will always remember a classic problem that existed prior to one particular hardwood flooring installation but went undetected. The installation commenced and was completed. Several weeks had passed before a complaint came to the attention of the hardwood flooring contractor.

The contractor, hardwood flooring manufacturer and the builder inspected the installation. The final walk-through with the homeowner had been conducted, escrow closed successfully and the structure was occupied. Initially, there were no apparent signs of the moisture-related problem that was about to plague the hardwood flooring installation.

The problem was brought to my attention by the local distributor who had supplied the hardwood flooring to the contractor. Sometime between the initial delivery of the flooring material and the installation, a basement window had allowed water to seep in over the sill, down the foundation wall to the concrete floor where it became a pool of standing water for an undetermined period.

The property had not been final graded at that point and the terrain sloped toward the basement window. If only the hardwood floor installer had gone down into basement, he would have noticed the standing water. Spring rains in the Midwest can be heavy and frequent. Of course, several weeks later, the water had time to evaporate and migrate into the subfloor directly beneath the hardwood installation.

Underlayment panel edges should be sanded to ensure a smooth substrate for a wood floor installation.
I recommended that they conduct a moisture test below the subfloor from the basement. Their readings came in at greater than 15 percent moisture content -- more than enough to cause expansion in the hardwood followed by cupping. I further recommended that the floor be allowed to thoroughly dry and, if the cupping was not too severe, it might revert to the acceptable flat surface that both the manufacturer and the contractor delivered and installed.

With regard to existing homes, the contractor needs to conduct the same moisture and relative-humidity tests. In addition, he should walk the outside perimeter of the home and check the slope, which should run away from the foundation and or slab. Gutters and downspots should operate correctly and drain tile should be used to transport water a safe distance from the home.

When the subfloor is not exposed because it is covered with existing carpet, moisture readings should be taken from the basement below the subfloor at joist level. Where water-supply lines are installed -- such as areas around as the dishwasher, ice maker, or the kitchen and bathroom sink connections, etc. -- check for leaks. Do so even if these particular areas are not part of the installation site. Remember, water can travel and it may do so unbeknownst by the homeowner.

And as always, acclimating the hardwood flooring material to the job site prior to the start of installation can minimize shrinkage during the dry heating season. A word of caution: don't acclimate until the job site is considered sealed from outside elements and the interior conditions are consistently dry.

Hopefully, Wood or Wood Knot has conveyed on to you just a few "eye opening" suggestions. Never become "blind" to the fact that two-thirds of the world is covered with water. All we ask is that you take the time to shore up your future installations.