In general, a table saw requires at least eight feet in front and behind to accommodate standard sheet goods and four feet side to side. A work table should provide four feet clearance on all sides, and pathways between tables, benches and storage units should be three feet wide. Proper clearance will allow you to move about with ease while you work.
Alternately, a detached shop can often be located closer to your property line and offers you a bit more freedom in terms of the type of foundation you can use. It may give you a sense of welcome separation from your home and open up yard space or allow a deck on the back of your house that would otherwise be lost behind your shop. In an urban setting, if you would like to have a wood stove in your shop you may find it more challenging to find an insurance carrier that allows one in an outbuilding. Also, outbuildings can be subject to more stringent height regulations than additions.
Let’s be clear about one thing: No workshop is perfect for everyone. If there were, I could simply give you a precise plan to follow with clear dimensions. Every person who comes to the hobby, avocation, or profession of woodworking has his own particular collection of tools and his own peculiar work style, skills, and desires for the kind of woodworking he wants to do that gives him a unique approach as to how he will lay out a shop: where the tools should go, where lumber and supplies are stored, and how much bench area he needs.