Some folks have built the entire airplane (other than to put the wings on) in a one car garage, which would be approximately those dimensions. I think that would be a bit challenging. But the tail, no problem!
I built my tail and my wings in a 2-car garage, while my wife was still parking in it. My fuse kit was delivered yesterday, things will get a little more interesting now...
I have built the tail, both wings, and the fuse of my 9A in the one-car side of a 2+1 garage - the equivalent of a normal 1 car garage. No expanding onto the wife's side !!!
That includes storing all the parts and airplane components. It can be done easily, but requires a bit of thought, especially for storage. You can buy cool shelves that go between the garage door and the ceiling (that's where my tail, ailerons, flaps, pushrods are right now). You can make a wing storage stand to hold the wings vertical (leadiing edge down) a few inches from each other to save space.
I started with 2 EAA workbenches, but am now down to 1 for space reasons. I'll be able to put the tail on, but when the wings go on the cars will go outside for a bit.
Go for it! Way better than a hangar, especially now that my garage has heat and A/C
Here is a link to a photo of my 10x20 garage when I started my project. There was plenty of room to build the emp. I built my wings in there as well. If you have a place to store your emp and wings once done, you can build the fuse in there too. A bit tight for space but not bad. It was always cozy. Get going!
