You might follow the link in my signature below to get some of my thoughts on room for chickens. It might help.
If you build from lumber you are buying, most building materials come in 4' or 8' dimensions in the most economical sizes. If you use those dimensions you can usually reduce waste and cutting to be more economical. An 8 x 12 would be easier to build and unlikely to cost much more than an 8 x 10. It would be a lot easier than a 7 x 13. If you have material on hand, use those dimensions.
I'd want a walk-in coop with roof overhang to get good ventilation under the overhang. The roof needs to be sloped so water runs off. Don't put your door where rain runs off over it. A single sloped roof is easier to build than a gable roof. A lot of different layouts can work but think in terms of your convenience. The chickens can adapt much easier than you can.
You can look under the coop sections under the Articles tab on here, a great resource. Or look for a shed design. You may find something online, often Home Depot or Lowe's have books available on how to build a shed. Those can be useful to show techniques.
A hoop coop may be a decent design for you. Your problem is that there are too many options, it may be hard to decide.
Then design for a minimum of 20, unless you decide you may want even more later. When thinking about space consider your run space also. Chickens don't think in terms of coop space versus run space, they think of how much space is available when they need it. In Northern Virginia your chickens can probably be outside practically all day every day which can take a lot of pressure off of coop size if you manage them in a way that space is available when they are awake.
If you build from lumber you are buying, most building materials come in 4' or 8' dimensions in the most economical sizes. If you use those dimensions you can usually reduce waste and cutting to be more economical. An 8 x 12 would be easier to build and unlikely to cost much more than an 8 x 10. It would be a lot easier than a 7 x 13. If you have material on hand, use those dimensions.
I'd want a walk-in coop with roof overhang to get good ventilation under the overhang. The roof needs to be sloped so water runs off. Don't put your door where rain runs off over it. A single sloped roof is easier to build than a gable roof. A lot of different layouts can work but think in terms of your convenience. The chickens can adapt much easier than you can.
You can look under the coop sections under the Articles tab on here, a great resource. Or look for a shed design. You may find something online, often Home Depot or Lowe's have books available on how to build a shed. Those can be useful to show techniques.
A hoop coop may be a decent design for you. Your problem is that there are too many options, it may be hard to decide.
