The Ontario Building Code | Fastening
(1) panel-type underlay shall be fastened to the subfloor with staples, annular grooved flooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">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.