Buying a garden shed (possibly online)?

Andrew1988

Sorry to jump on the back of this thread, but has been really educational reading it. I'm hoping for some advice...I have an alley between my house and garage width just over 1m. I plan on building a long shed 3m x 1m. Is it best to leave a gap from the walls for air or join them to both walls? There is decent coverage from a tree so rain and wind will not be a mjor issue but still want to make it watertight..just not too sure on the brick walls..as don't want to cause damp by restrickiing air flow etc any advice would be very welcome.