On 19/02/2019 18:36, John Rumm wrote:
snip

If I've found the right density and done the sums right[1] it's around
360kg. I can see 40mm uPVC taking that when spread evenly over the 2
lengths but wondered about when the slab is only partly on. Fill the
pipes first?

Slap some wooden battens down them if unsure. Having said that, I can
easily stand on a solvent weld pipe without crushing it or making much
impression at all - and that is 100 kg as a point load. You could just
use timber, but the pipe would probably be more slippery.

Thanks John.

It seems even the oddment of uPVC I had is inferior to your pipe


--
Robin
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