On Mon, 6 Oct 2003 09:41:18 +0100, Christopher Norton wrote:

The design requirement for a man load on flat roof joists will mean it
can carry almost as many growbags as you require.

Loading is almost certainly not a factor in this case. If you want me to
check then get the size of the flat roof joist, with the longest
distance between supports and I`ll do a quick calc to prove the loading
for you. 8-)

One important difference, however, between the load that roofs
are designed for and the load imposed by plant pots, grow-bags,
and such: the latter are a permanent load, whereas snowloading
(the only real weight a roof takes) is transient in temperate
climates, coming and going through the winter. (Heavy snowfall
areas have steeper roofs than low snowfall areas, so the load is
simply shed to the ground.) A load that causes no damage in that
time frame may produce significant settling and warping after six
months or a year or so.


--
Rodger Whitlock
Victoria, British Columbia, Canada
change "invalid" to "net" to respond