Thanks for the reply guys.
Basically there will be a 3x3 meter ply or chip board floor and then a Titan (to keep with the Astronomy theme

)steel frame g
arden shed the same as this one. So as far as weight being carried, very little.
Al, the pier will be completely independent of the floor so no weight there.
About the only other weight will be the weight of a desk and computer....oh and fridge, lounge chair, foot stool....