Ventilation: Approved Document F, Volume 1 — Dwellings

O N L I N E V E R S I O N F1(1) 1.40 A dwelling with a basement that is not connected to the rest of the dwelling above ground level by a large permanent opening should be considered as follows. a. The part of the dwelling above ground level should be considered separately. b. The basement should be treated separately as a single-storey dwelling above ground level. c. If the basement has no bedrooms, it should be treated as having one bedroom when calculating the ventilation required for the purposes of meeting the ventilation standards. 1.41 A dwelling that is only a basement should be treated as a single-storey dwelling above ground level. In such circumstances, the guidance for dwellings without basements should be followed. The guidance on natural ventilation, however, is not appropriate for a dwelling that is only a basement. Ventilation of a habitable room through another room 1.42 If a habitable room does not contain windows that can be opened (e.g. an internal room), the requirement to provide adequate ventilation can be met using paragraphs 1.43 and 1.44. This guidance can be used if the room is ventilated through either of the following. a. Another habitable room. b. A conservatory. 1.43 The habitable room or conservatory should have openings to the outside to provide both of the following. a. Purge ventilation with a minimum total area given in paragraph 1.29, based on the combined floor area of the habitable rooms (or the habitable room and the conservatory). b. Background ventilation of at least 10,000mm2 equivalent area. 1.44 Between the two rooms there should be a permanent opening with a minimum area of 1/20 of the combined floor area of the two rooms (see Diagram 1.3). Permanent opening based on 1/20 of the combined floor area Purge ventilation opening, see paragraphs 1.26 to 1.31 10,000mm2 background ventilator Diagram 1.3 Two habitable rooms treated as one room for ventilation purposes 13 Building Regulations 2010 Approved Document F Volume 1, 2021 edition O N L I N E V E R S I O N