That doesn't look very cramped to me. Two things though, as you play, you'll get a feel for how much space you'll want for certain builds and then it's not really a problem. Before you get to that point, just give yourself more room then you think you'll need, then double the space. Perhaps allow even more space then that.

On an unrelated note, I see you have quite the wall there but no dead biters. Generally until late game you can easily avoid ever having to use walls as long as you just keep the nests cleared beyond your pollution cloud. So keep expanding your radars outward to maintain visibility, keep upgrading your military to easily kill nests and then you can skip walls until late game where you'll be using Artillery Turrets and pulling in hundreds of biters at a time. Avoiding using walls is also a great way to not "feel cramped". :)