NEW Porch - structural question.

[twm.bwen]

Hi there, I'm going to be building a 1000x1600 twin pitch clay tile roof porch and even thought it doesn't need buidling control approval I still want to build it well.

the final design is still unsure between single 150 skin sandstone dwarf wall to 800mm then glazed or same sandstone to full height with dinwos either side.

So I guess I should build the footings to take the full wall, but the question is this (are these)....

Are 300wx100deep strip foundations sufficient?
How deep should they be?
Should I lay a layer of blocks to above ground level then dpc then sandstone? (if so what ties the sandstone to the footings?

In between the walls I will lay 100mmthick slab over 50mm jablite that is over dpm over 50mm sand over normal earth. Is this correct or must I put in hardcore?

I was planning to tie the whole thing in using frame screws (for glazed option) or rawl plugged wall ties (for solid wall) and expansion bolts to tie the rooof structure to the external wall and wall plate strapped to walls for the structure to sit on.

Does this sound about right?

thanks for any advice and opinions,
Tom

 

[noseall]

dig the foundations down about 600mm minimum providing it is virgin earth. pour the foundations at 300mm wide and 200mm thick.

you would also be better laying 100mm hardcore beneath the floor slab too.