Definitions

In this Technical Booklet the following definitions apply – Contaminant – is defined in regulation 25 in Part C of the Building Regulations. Drain – is defined in regulation 2 in Part A of the Building Regulations. Dwelling – is defined in regulation 2 in Part A of the Building Regulations. Floor – is defined in regulation 25 in Part C of the Building Regulations. Ground water – water in liquid form, either as a static water table or flowing through the ground. Interstitial condensation – conversion of water vapour to liquid water which occurs within or between the layers of a construction. Moisture – is defined in regulation 25 in Part C of the Building Regulations. Precipitation – moisture in liquid, solid or semi-solid form falling from the atmosphere, usually as rain, sleet, snow or hail. In this Technical Booklet, the term 'precipitation' includes spray blown from the sea or any other body of water adjacent to the building. Radon affected area – is defined in regulation 25 in Part C of the Building Regulations. Roof – any part of the external envelope of a building that is at an angle of less than 70° to the horizontal. Site – in relation to a building, means the area of ground covered or to be covered by the building, including its foundations and the ground adjacent to it. Spray – water droplets driven by the wind from the surface of the sea or other bodies of water adjacent to buildings. (Sea spray can be especially hazardous to materials because of its salt content). Vapour control layer – a layer intended to limit the transport of water vapour through the building fabric by diffusion or by air movement. Wall – is defined in regulation 25 in Part C of the Building Regulations.