What size foundations?

[boathail]

I am planning to build a single story small extension to my kitchen to include a tiny ventilated passage and a small toilet area.
What size footings do I need? I am guessing at 18inch by 12inch but am not sure....
There is no chance at all of there ever being another storey built above.

[boathail]

Yes thanks Zacsmaster. As I live out in the country and the little extension is going on the back of the property, I thought that I would just get on with it without the paperwork. It will measusre approx. 10feet by 4feet and stand approx 8feet high. I have heard that planning permission is only neccessary if the building work is over 8 feet high , but spose the bloke in the pub could be wrong...