Detached 4 car garage

[Eddman]

Hi there - designing a 12m x 7.5m four car detached garage. It is to be Permitted Development and therefore needs to be brick external leaf. Speaking with a builder, he says if i build with 4" brick external and tied to abutting 4" block solid wall that will be strong enough (and an economical way) to build it. I was going to just show a 100mm brick 100mm clear cavity 100mm block wall. Is the solid wall a better option? Or would it be better in a single skin of brick with piers at 3m intervals (or less)? The side gables will be 7.5m long and 4m tall to top of gable...

Thanks

 

[^woody^]

Single skin

 

[Eddman]

with 337 x 337 piers? The garage is near some Douglas Firs trees too - so i am going to need foundations to depth of 1.75m - i was thinking of digging pads 600x600x1750 deep every 2.4m and installing concrete lintel/beams then building wall on top of that - rather than a full trnech fill all around the perimeter at 1750mm deep....Does this make sense? Obvioulsy this is going through building regs...