Repeated surface licking can have more than one cause. A dog might be investigating a smell, but persistent or new licking can also accompany a medical problem. Do not decide it is boredom or anxiety before checking their health and the surface itself.
Move cleaning chemicals and anything they could swallow out of reach. If your dog may have licked a chemical, swallowed a foreign object, is retching, vomiting, painful, bloated or unusually weak, call a vet urgently. For repeated episodes without those signs, book a veterinary assessment and describe when it happens, how long it lasts, what they lick and whether appetite or stools have changed. A brief video can help your vet see the pattern.
There is evidence that some dogs with excessive surface licking have gastrointestinal conditions, though it does not diagnose your dog. A veterinary behavior assessment may be useful after medical causes have been considered. Avoid punishing the licking or putting bitter substances on a floor that may already be irritating them. If they lick their paws as well, the paw-licking article describes what to check on the skin, but neither pattern should be dismissed without veterinary assessment.
Today, make the surface safe and record one episode if it happens. The next step is finding the cause, not merely stopping the visible behavior.
Sources: Clinician's Brief on gastrointestinal findings in excessive surface licking, VCA on medical rule-outs for repetitive behaviors, Dogs Trust on household toxins.