Garden room / deck concrete pad and posts help

[Noodle]

Hi All,

 

After a little advice/ thoughts on my pads/ beam and and joists dims for a smallish garden room/ deck i'm building. Its on a fairly substantial level change - approx 1m.

 

See attached sketches that hopefully explains well enough, perhaps i'm over engineering here, but perhaps not!

 

- Basic premise is footprint of approx 5000mm x 2500mm. 2 rows of 4 pads to make 4 short beams running front to back. Posts to be tripple 2x6s ( too much!?) to double 2x6's for beams with 2x6s joists on hangers. Beam spans will be approx 2000mm between posts, and joists span 1700mm.

 

- some simple cross bracing to posts

 

- Single story timber frame building with cedar shingles 3m width and then 2m width decking. 

 

- Concrete pads approx 400x400 x tbc depth with post shoes cast in to hold above ground level

 

- Ground is soft topsoil but down to much harder sand/ clay.

 

Any thoughts/advice appreciated.