I am in the planning phase of my coop, and have started drafting up a concept. This will allow me to calculate (as accurate as possible at this phase) the costs and materials that will be needed. I have been playing with 3D software for a while for other projects, and while I am no expert, I believe this will give me measurements as close to accurate as I can get at this stage.
As a side note: This is all still a concept pending feedback from more experienced keepers. I do not include many of the finer details in the concept (e.g. extra support for the floor and roof, door hardware, roosts, trim around the coop walls, doors, etc.) as I was mainly trying to focus on the size, and more prominent features like the nesting box, that are for the welfare of the chickens. Any nice to haves for the owner (me) are not included at this point.
The current idea is that the primary ventilation will be through the roof, and the at top of both the front and back walls. Since I am in East Texas, the winters are normally very mild and my main concern will be dealing with the heat (that frequently reaches 100°+ during the summer months). The good news is that I can supply plenty of shade, thanks to the towering pines on the property, and we always have a breeze blowing through.
First, I started off with the rough dimensions of a sheet of plywood, (4' x 8') and laid out the main support structure. With this design, I will be able to use a full sheet of plywood for the floor, with only minimal cuts to the corners. I opted to go 7' tall on the main supports, so that when the roof is added, there is plenty of room for me to maneuver around with running into anything. This allows an inside height of roughly 4.5', so I can always send a kid in to do the dirty jobs if needed.
Next I moved on to the walls supports, and ventilation framing (hiding the previously shown walls in the second image in order to highlight the additions). I am still trying to determine how I will line the floor, but I am leaning towards to using Fiberglass Reinforced Plastic (FRP) Wall Panels (which I happen to have left over from another project). It is normally used around wet locations, such as shower stalls, and is moisture-resistant, cleanable and will not mold or mildew. That will allow me to hose out the coop floor if I ever need to do a deep cleaning. Otherwise, I will stick to vinyl flooring.
Then I moved on to skinning the walls and adding in hardware cloth for ventilation areas. Around this time in the concept, I started to think about moving the pop door to a floor exit - but that is still up in the air at this point.
The last structure at this stage was the nesting box, which will be accessed from outside the coop. The nesting box will have three compartments, each compartment coming in at just over 13" square. If my calculations so far are correct, I will only need 5 sheets of plywood, and have enough material left over to complete the nesting box and doors! Based on other comments I have seen here in the forums, three should be enough space for 6 hens.
After adding an elevated roof and adding the hardware cloth under the coop, I ended up with a design that resembles a shoebox - nothing too fancy. Overall, this gives me just shy of 32 sq. ft. and enough for my planned flock of 6 hens, possibly 8...
The next step will be figuring out the full materials list!