sarking

Noun

 * 1)  Wood, felt, or other material placed under the shingles of a roof in order to provide support or insulation; the practice of furnishing roofs with such material; an installation of such material.
 * 2) * 1997, Ann Ross, Jonathan Hetreed, Architect′s Pocket Book, 2011, 4th Edition, Elsevier, UK, |%22sarkings%22+-intitle:%22%22+-inauthor:%22%22&source=bl&ots=iyGlLCUDUD&sig=J85GnIHP4GUwsWB1-fPA2sA2X8I&hl=en&sa=X&ei=ESAqUP_UM6qOmQXL54G4BA&redir_esc=y#v=onepage&q=%22sarking%22|%22sarkings%22%20-intitle%3A%22%22%20-inauthor%3A%22%22&f=false page 248,
 * Sarkings are weatherproof membranes laid over rafters and below battens to draught-proof and weatherproof the roof against driving rain or powder snow that may penetrate the tiles or slates.
 * Traditional sarkings of reinforced bitumen felt have been largely superseded by lighter, breathable sarkings that can be laid to form an effectively draught-proof roof but still allow free dispersal of water vapour to avoid roof space condensation; such mterials generally avoid the need for eaves, ridge and roof slope ventilators. Where they are laid directly over insulation between rafters, or over a permeable sarking board, tiling battens are raised clear of the sarking by 25 x 50 counter battens nailed down to the tops of the rafters.
 * Traditional sarkings of reinforced bitumen felt have been largely superseded by lighter, breathable sarkings that can be laid to form an effectively draught-proof roof but still allow free dispersal of water vapour to avoid roof space condensation; such mterials generally avoid the need for eaves, ridge and roof slope ventilators. Where they are laid directly over insulation between rafters, or over a permeable sarking board, tiling battens are raised clear of the sarking by 25 x 50 counter battens nailed down to the tops of the rafters.