Contrary to popular belief, squeaky floors are not just an ‘old home’ problem. Most squeaks originate in the finished flooring (especially from poor installation of hardwood) but
occasionally they can be in the sub-floor system if the proper care is not taken during installation. Sub-flooring systems built to minimum code requirements are more susceptible to squeaking over time.
Minimum code can allow for joists depths to be smaller and thinner sub-floor panels but the cost to build to higher than minimum code requirements is not a lot. Keep in mind that finished flooring like ceramic and hardwood require thicker sheathing and sometimes closer joist spacing to carry the dead loads. Ensuring an effective sub-floor system that doesn’t result in noisy floors takes some care and attention to detail both before construction starts and with the installation of materials.
Nailing
Take care that the joists are nailed correctly and if joist hangers are used that they are installed and fastened completely (those holes are there for a reason). There have been many inspections for squeaky floors that turned out to have missing nails in the hangers that allowed the joist to move. Nail guns are great, but only when they are adjusted properly and used correctly. Nail guns not adjusted properly can overdrive or under driven fasteners and that results in the sheathing not being secure. Under driven nails can also cause issues when it comes to installing the finished flooring. When nail guns are used you can’t tell when a nail has missed or partially missed a joist. Panels that can move up and down on that nail are very likely to cause squeaking when walked on. Check for shiners and refasten all required areas and, if possible, remove the shiner.
It is extremely important to follow the manufacturer’s nailing instructions and/or the local building code or design professionals specifications as they may vary depending on where you are building.
An even better option is a combination of adhesives and fasteners. See the next blog for more on these.