Designing a shed on posts - choosing joist sizes etc

[Cigaro]

Hi,

I am designing a 10x6 workshop/shed. I'm currently designing the base, and because the entire garden is on a slope I want to do something like this:

The front side will need to be raised around 47cm one one end and 37cm on the other to make the whole thing level. Pouring a concrete pad etc is not a good option so I was thinking of using a 'post and pier' construction like above, of the sort you may used for a raised decking.

With trying to keep costs down, I need to decide on the size of lumber to use. I need the joists at a maximum of 1m centers because I'm using floorboards which come at that length. The design I came up with above is all 4x2 at 500mm centers. Should I use 6x2 and, if I did, should I stick with the 500mm centers or go to 1m?

Are two "sistered" 4x2s ok for the posts?

I realise I may be putting a little too much planning into this but the shed will need to support 5 years' worth of collected tools and assorted junk, a workbench, and maybe at a later date a small metal lathe.

I want to get the base done this weekend so if anyone has any suggestions that'd be grand

 

[munchingB]

i wouldnt use anything smaller than 6x2 for the frame on the floor and the floor joists.

 

[Deluks]

Pouring a concrete pad etc is not a good option

I disagree, pouring a concrete pad is a very good option, at least for the timber posts in the 'deep end' Bolt your post to the framework, then at least it's removable and replaceable when the bottom starts to rot.

At the 'shallow end' Place bricks under that framework, missing a few out for airflow.