Length, type and the three zones of an entry
An effective entry has three functional zones. Outside the door, a coarse scraper surface removes the bulk of loose material. Immediately inside, a wiper mat removes finer grit and moisture. Beyond that, a transition surface catches what remains before people reach the finished floor. Most buildings have only the middle one, at about a third of the length required, which is why the finished floor is doing work the matting should have done.
Length is the variable that matters most. General guidance across the industry is that several strides on matting are needed to remove the majority of soil from footwear, and a single mat inside the door delivers perhaps one. Extending the matted run is inexpensive relative to refinishing a floor, and it reduces the required frequency of floor work rather than adding to the cleaning burden.
