Garden room foundations depth?

[darkkent8]

So i am looking to construct a small garden room 2.5x3m external size - 2.5m height
I was just going to lay and insulated slab and construct a timber frame but I have a bunch of thermalite blocks leftover from our recent extension so want put those to good use. Then baton the wall and use PIR insulation and clad the outside (just as if i wasn't using the blocks

I am just looking to get some advice and on depth of foundations for something like this

Not building yet but just planning in advance

I have attached a picture of my thoughts

Any help would be greatly appreciated




I think i may have posted in the past but didn't really have any info about sizes or a plan

 

[motorbiking]

Why not go with a smooth render (external), block, PIR (bondonded with plasterboard foam) and them plasterboard (bonded the same). No need for battens anywhere.

Add a DPM in the concrete base and run into the block. Sit it on 450m x 450x. If you go for 50-70mm PIR, you aren't going to be too far off building control compliant U values.

I know this is bigger than your are planning but a finish like this: