Yellow Tounge over Floor Joist & Beares /

[PlasterPro]

I am about to lay some yellow tounge over joists(90mmx45mm @ 450 centres) on bearers (90x90 @ 1250 centres)
first question is, what sort of spec should timber be ?
have already done one room in house useing this dimention timber and can`t rember if it was just straight kd hardwood.
Room is 3.6x3.7 apx
second question what size can i get yellow tounge in as i need it at 3.7 so a 4.0 or 4.2 would be good (is 3.6 the biggest size?) should come in 1200mm yeah?
third question , how deep should i sink concrete post in groung -have been working on 500mm-600mm?

thanks in advance

[TermiMonster]

The standard yellow tongue is 3600 X 900mm. I have never seen it larger, but that doesn't mean you can't get it.
Can't help you with anything else off the top of my head.
TM

[PlasterPro]

900mm wide will be 4 wide,
but a bugger that 3.6 is the biggest, shame to have to put butt joins in...