What the fabric will and will not take
Porous sandstone and unglazed brick absorb whatever is applied to them, which means a strong cleaner leaves residue that draws moisture and salts back to the surface over the following weeks. Timber stair treads in a service stair swell and cup under repeated wet mopping. Original floor tiles are often laid without a modern membrane, so water finds its way into the bedding.
The practical response is drier methods and gentler chemistry applied more often. Damp mopping rather than flooding, neutral products rather than heavy alkalines, and mechanical removal of debris before any liquid is introduced. The scope should record each surface, the method chosen and the reason, so a substitute attendant does not default to the fastest technique available. Where the same surface appears in several places, recording it once and referencing it keeps the proposal readable for an occupier who is not a facilities professional.
