Approved Document M Volume 2 wants entrance thresholds level, and where a raised one cannot be avoided it caps the total height at 15mm. The catch is that every layer in the doorway counts: cill, weather bar, seal rebate and new flooring. This guide shows what the rule says, where site installs fail, how fire door seals fit in, and a pre-order checklist. It is written for hotel owners, HMO landlords and contractors specifying doors in England.
Hotel & HMO refurb
Electrics, bathrooms, hotel housekeeping and fire safety from a single supplier. BOMs by room type, UK compliance checklist.
Read the hotel refurb guide

