What Causes Squeaky-Creaky Floorboards?

There is nothing worse than tiptoeing around your home while people are asleep and hearing a harmony of squeaking floorboards. Nearly all homes have at least one floorboard that groans as people walk over it. You become accustomed to hearing the squeak each time you walk on that plank and avoid the area while your wife is asleep. These squeaks and creaks become ambient noise in a house full of people. However, floorboards aren’t supposed to creak at all. After installing the wood floors the home begins to settle, which creates these distinct sounds. These creaky noises are incredibly annoying for most homeowners, and oddly one of the many things you miss after you have moved out of the house. If your home has creaky floorboards it’s important to understand how heat causes the floorboards to shrink, how loose nails make the floors squeak, and how to fix these annoyances. 

Wood holds water for many years after the tree is chopped down and turned into floor planks. The moisture in the wood slowly evaporates until it reaches an equilibrium moisture content, where the moisture in the wood is equal to the moisture in the air. When this happens, the floorboards shrink just enough for them to rub against each other, instead of being held firmly in place. This rubbing causes the unique squeaking sound that drives you mad. The process accelerates during cold winters that force you to use the heat for several months at a time. The unnatural heat circulating the home drops humidity levels below 40%, which causes the boards to shrink.

The constant shrinkage and swelling of your floor boards will loosen the nails just enough to produce a squeaking sound as the wood plank rubs against the nail when weight is applied. The higher pitch of wood rubbing on nails is noticeably different from the groaning of wood planks rubbing against one another. This sound is often heard before you notice there is a nail head slightly raised. 

To remedy the symphony of groaning floorboards you must first locate where the floor is creaking. If possible, go into your basement and have someone walk around above you, so you can locate the exact location of the noise. Otherwise, carefully walk around the floor checking each section where the boards are nailed to the subflooring. For noises causes by shrinking you should lubricate your floorboards with an inexpensive product to add more moisture to the wood. 
If the shrinking caused gaps to form between the joists, then you should fill the gaps with caulking. The ideal humidity level for wood flooring is between 40-60%, so save yourself the trouble and keep your house within those parameters. If your floors are creaky because of loose nails, you should hammer in all the nails, and drill screws into planks that had severely loosened nails. If you have found that there are several creaky boards along one specific joist, then you should install a block between that joist and the one next to it.