Edwin Pawlowski wrote:
"DaddyMonkey" wrote in message
...

I have read how to install tile over plywood flooring at various
websites.

They say the maximum floor joist should be 16" on center with 'a
maximum deflection of 1/360 of the span, at midpoint.'

What does this mean? 1/360th of an inch movement (up & down) between
joist?

I saw this at Super-Tek.com

Thanks,
Dave



If the span is 20' that is 180". If you divide that into 360 segments, you
get 1/2"


It means the floor joist is not suppose to bend more than 1 degree at
the mid point. The industry claims greater deflection will cause the
tiles/joints to crack if more than that. This can be true when you get
into larger tiles.