Ceramic tile sheet.
Black spots on engineered hardwood.
To remove dark water stains from wood floors you have two options.
Last january i was commissioned by a flooring manufacturer to inspect a prefinished 3 inch engineered oak floor that had developed dark spots.
Over several weeks and even months the mysterious crud spread onto adjoining floors and materials.
With the proper care hardwood floors will last a lifetime.
The homeowner was convinced the flooring was defective and wanted the floor replaced.
For more on black spots see my previous article what causes mysterious black spots in wood floors.
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 wood can also appear due to prolonged exposure of water and metal nails forming the iron oxide.
I considered black iron oxide contamination but such spots encapsulate once the finish is dry and do not spread.
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.
The use of the best hardwood steam mops is recommended for sealed floors.
It reacts with the tannin in the wood and turns black.
These discolorations will cause your hardwood floors to look old and dingy.
Dip a small brush such as a toothbrush into a small amount of bleach and rub onto the stain.