The greatest enemy of any wood materials, but particularly of hardwood flooring, is high and varying moisture levels. It makes the wood fibers shrink and swell and, over time, can actually cause the wood itself and the surface finish to deteriorate.
Your brief description of the flooring problem in your current house indicates you probably experienced edge crush. The hardwood flooring pieces probably absorbed moisture before the surface was finished and sealed. This allowed moisture to enter the wood, causing it to swell.
Most hardwood flooring uses a tongue-and-groove edge design to lock the pieces together. Although the edge appears to be perpendicular to the surface that you walk on, it is actually slightly tapered. This allows room for imperfections and pieces cannot be laid tightly together.
If the floor is laid and moisture causes it to expand even a little, this tapered edge gets crushed. When the floor finally dries out and shrinks back to its normal, stable size, a gap between the pieces is created. The only way to fix it is to fill the gap with wood filler.
Proper installation of your new hardwood floor can eliminate this problem. If you are going to try to lay the floor yourself, contact the following two organizations to request their hardwood flooring installation guides: National Wood Flooring Association (800-422-4556) and National Oak Flooring Institute (901-526-5016).
Careful handling of the hardwood flooring material is critical, especially during new construction, to avoid any moisture problems. Hardwood is kiln-dried to a precise moisture content before it is milled to size.
The stability of the moisture content is more important than the moisture content level itself. Keep in mind that the wood does not have to get wet for problems to occur. Water vapor in the air can be absorbed into the kiln-dried hardwood material.
The key to a long-lasting, attractive hardwood floor is not to install it until the moisture levels in the rooms in your new house have stabilized. Concrete, framing lumber, drywall, and even paint will elevate the moisture level indoors.
Once the moisture (humidity) level indoors becomes somewhat stable, stack the hardwood in the various rooms where it will be installed for at least five days. This allows its moisture level to match that of each room. Do not move the hardwood from the store to your house on rainy or extremely humid days.
It is important to install hardwood flooring over only rigid, approved subflooring. If the furnace or water heater (warmer areas) is located under the hardwood flooring, install some insulation above them. This will keep the wood from drying out in those areas and shrinking.
Even after your hardwood flooring is sealed with glossy, tough urethane, never use water to clean it. Do not mop it with cleaners, solvents, oil soaps, etc. These can damage the surface. If you have wipe up a spot, wipe it with a well-wrung washcloth and then immediately with a towel.
Do not use wax on your flooring because it makes it difficult to refinish it in the future. You might consider screening it every two years. Screening basically just roughs up the old surface and removes imperfections. Apply a new finish and you can avoid ever having to do an expensive complete re-sanding/finishing job.
