(1) Panel-type underlay shall be fastened to the subfloor with staples, annular grooved flooring nails or spiral nails, spaced not more than 150 mm o.c. along the edges and 200 mm o.c. both ways at other locations.
(2) Nails for panel-type underlay shall be not less than 19 mm long for 6 mm thick underlay and 22 mm long for 7.9 mm thick underlay.
(3) Staples for panel-type underlay shall,
(a) have not less than a 1.2 mm shank diameter or thickness with a 4.7 mm crown, and
(b) be not less than,
(i) 22 mm long for 6 mm underlay, and
(ii) 28 mm long for 7.9 mm and 9.5 mm underlay.