Passive radon methods can be categorised into two types Basic radon protection and Full radon protection each of which requires a gas proof membrane laid within the floor structure.

Four basic floor types have been identified including ‘Concrete ground bearing floor’, ‘Concrete ground bearing floor built into cavity walls’, ‘Precast concrete (beam and block) suspended floor’ and ‘Timber floor’ that are used to provide radon protection to dwellings.

Various materials can be used to provide the radon barrier including polyethylene, roofing material, prefabricated welded barriers, liquid coatings, self-adhesive bituminous-coated sheet products and asphalt.

It is important to remember that radon is a gas therefore great care must be taken to achieve as gas tight a seal as possible between all parts of the barrier. Problems in it’s formation such as joining, joining to other materials, building into the cavity walls, forming the cavity tray, cutting and shaping around service penetrations and working in adverse weather conditions may be apparent at site level.