Make Sure the Floor Is Level
Always make certain that your washing machine and clothes dryer are installed on a level flooring surface. If your hardwood floors are even the slightest bit slanted, it can increase the chance that your washing machine and dryer will shake or sway when they run, thus harming the floor. Rest one hand on each side of the washing machine and try to move it back and forth. Do the same with your dryer. If one or both appliances move, it's an indication that they're not steady. On the bottom corners of each appliance is a set of four adjustable feet. Use a wrench to loosen or tighten the bolts until the appliance is stable on all four corners.
Don't Overload
Specifically, avoid overloading your washing machine with laundry, but also your clothes dryer. Overloading your appliances increases the weight on the drum, putting added strain on its spinning ability. The harder it is for a drum to rotate, the greater likelihood that it will pound and thump on your hardwood floors when the appliance runs. Pause the appliance mid-cycle when you hear a rocking noise. Remove some of the laundry inside so that the drum is a little more than half full. Also make sure that the remaining clothes in the washing machine are spaced out evenly, to ensure that the drum rotates smoothly.
Place Plywood Underneath
Hardwood floors are prone to shocking from washer and dryers as they operate. Shocking is when a machine hits against the floor, producing dents and marks that destroy the wood's glossy finish. Installing a 1-inch-thick piece of plywood below the washer and dryer provides a barrier to protect your hardwood floor from shocking. The plywood absorbs not only vibration but also noise produced by your appliances when they perform.
Use Anti-Vibration Pads
Place anti-vibration pads obtained from an appliance retailer beneath your washing machine and clothes dryer to safeguard your hardwood floors. The pads serve as a protective barrier between your appliances and floors to keep them from becoming ruined if your washer or dryer knocks against the floor and, in the case of your washer, leaks. Although the pads won't stop your appliances from vibrating or leaking, they'll work to minimize any damage done to your floors.