Foundations for brick porch?

[Candyman21]

Evening,

Just wondered if anyone could give me an idea of depth and width needed for a brick built porch? I don't need planning permission as long as i don't go above 3 meters in height and external walls don't measure more than 3 square meters.

I am just unsure of what depth to go down, how deep the concrete needs to be and also how wide?

Any help would be greatly appreciated

 

[^woody^]

Down to firm ground is the text book answer. That might be 750mm minimum, deeper in clay.

Twice as wide than the wall is thick

 

[Candyman21]

Thanks for the reply, so if i were going to use double skin i would make the width 600mm? If i dug down 750mm how thick should the concrete trench be? Am i right in thinking engineering blocks up to dpc on the outer later and medium density blocks top to bottom inside layer?

Thanks again for your help with this.