Big Bearers & Joists

The design of the sub-floor is taken direct from Australian Standard 1684. However, previous experience has shown that when joist spans approach the maximum limit, floor bounce can show up as a problem. So I have used a conservative design approach. All bearers are 90x90 F17 SHW (normally 90x70), and my joists are 90x45 F17 SHW (often 90x35). Bearers are spaced 1650max, and stumps are spaced 1500max.