Deflection in timber sub floors

[Ian Harris]

Does anyone know of any authorative publication that specifies the allowable deflection tolerances in wooden suspended floors when laying marble tiles
(in my case 600x600x20thick)
Cheers
Ian

 

[Rob Z]

Hi Ian, I know this won't help you or be a binding standard in the UK, so I just offer it up in case you're interested...

Our TCNA (Tile Council of North America) and the MIA (Marble Institue of America) use L/720 as a "standard" for deflection of the substrate under natural stone.

 

[Ian Harris]

Rob
Thanks for that
Coincidentally the client is an American so perhaps I should be looking at US standards!
So far I have been unable to find any authority in the UK that will commit on deflection allowances
Some informal advice is L/1000 but this is practically a concrete floor
L/720 sounds more practical
Cheers
Ian

 

[dilz000]

I'm pretty sure you don't want any movement at all so why give it a tolerance :s

 

[Ian Harris]

Zero deflection is the ideal but nigh on impossible to achieve on a suspended timber floor
so it is a matter of establishing what is acceptable

 

[peckers]

20mm stone will add alot of weight to a suspended floor dont forget to take this into consideration...