Dark spots on hardwood flooring are commonly the result of some type of liquid that has soaked into the polyurethane finish and top layers of wood.
Black spots on engineered hardwood.
Last january i was commissioned by a flooring manufacturer to inspect a prefinished 3 inch engineered oak floor that had developed dark spots.
Black rings or dark water marks can be more problematic as these are generally water stains that have penetrated into the finish of the floor.
Ceramic tile sheet.
With the proper care hardwood floors will last a lifetime.
To remove dark water stains from wood floors you have two options.
Over several weeks and even months the mysterious crud spread onto adjoining floors and materials.
For more on black spots see my previous article what causes mysterious black spots in wood floors.
The gulf coast area home was late 1970s construction with a concrete slab.
However items such as oil water grease and pet urine will create black spots on the hardwood floors.
The homeowner was convinced the flooring was defective and wanted the floor replaced.
Dip a small brush such as a toothbrush into a small amount of bleach and rub onto the stain.
It reacts with the tannin in the wood and turns black.
Unlike white water stains residing on the very surface of the hardwood floor dark stains require more steps and products in order to restore the beauty of the wood.
These discolorations will cause your hardwood floors to look old and dingy.