One of the biggest problems that we find in Illinois is dealing with an adequate quality of existing subfloors that were used. Most new builders in the area cheap out and use chip board instead of traditional plywood as the subfloor to save a few thousand dollars on a new house.
The problem is that we are usually dealing with the second owner of these homes and they are unaware of the subfloor issue. We explain to the customer the problems that have occurred such as loose boards and squeaks. With the poor subfloor, we offer our suggestions to improve the situation. Our first suggestion is to remove, glue, and replace the worst areas of loose pieces. Other times, if allowable, we will screw boards from below.
Living out West in a market where most of our homes have concrete subfloors, we see an immense amount of flatness issues. I am not saying “level,” but “flat.” There is a difference! On almost every home we work in, we will have to do concrete grinding to remove high spots and/or self-leveler/patch to address the low areas. We mark these at the start of the job using concrete markers: blue for the low areas and red for the high spots. This makes it easy to see and also identify that these problem areas have been addressed. These issues are often unforeseeable on a remodel and result in change orders. This can be a tough conversation to have with your customer, but I promise they want their floor installed properly. Have this conversation before the start of the project, and it will not be a total surprise.
Since most of my area in the Southeast is slab construction, the failures I am called out on are actually in two categories: moisture damage and being out of flat. These issues are seldom immediately visible. It could be weeks or months after the installer has been paid and no longer around when the homeowner is stuck with the failing floor. For moisture damage, the company/installer usually did not test for moisture, or did not apply a proper vapor barrier before installing. Installation over uneven, out-of-flat slabs is also a major failure. Typically, homeowners are not educated about this issue and the floor store or installer is afraid to bring up slab prep for fear of losing a sale/job. They do not recognize the loss of goodwill they suffer afterward. The owner isn’t going to have very nice things to say when they are among friends and family about a company that didn’t service them properly in either situation.
A common issue that I’ve seen in Western Canada is noisy floors as a result of nailing down flooring over subfloors with excessive deflection. Many installers believe that if a subfloor meets the minimum requirement for subfloor panel thickness and joist span, it is acceptable to nail down any type of hardwood flooring. Sometimes, even though the subfloor meets the minimum standard requirement to meet with local building codes, there may still be too much deflection to nail down certain types of flooring. Nailing down thin engineered over a subfloor with excessive deflection will often times lead to squeaking or popping floors. When faced with these issues, installers will either employ a glue-assist method of installation or adding more plywood to the subfloor to reduce board-to-board movement that may cause squeaking. Make sure that the end-user is aware of the extra cost associated with this type of installation since adhesive or plywood must be purchased, and the installation will take more time.
In the upper Midwest, the failures found in the subfloor are often related to the weather we experience. It depends on the construction of the subfloor (e.g., plywood or OSB), but these products are still comprised of wood, which makes them vulnerable to the elements. Most builders don’t understand the importance of protecting the subfloor from the elements, and if the subfloor is exposed to those elements, the products need to be dried out before the wood flooring is delivered or installed. The failure could occur in the plywood or OSB, which has the potential of delamination or will expand due to the absorption of the water with which it comes into contact. The contractor will not likely see these failures until his wood floor has been installed.