inside length a bit over 8', width 5' 2", interior height 5' 2". I,m 5' 9 1/2" so I can stand up hunched over a bit. Makes it nice for getting dressed in the morning. Plus in the evening if your sitting inside it actually seems quite roomy. The roof slopes down a bit in front to eliminate the box look and also aid in water runoff when parked. I used the roof from a wrecked tent trailer, it's a 1" thick foam core piece and it fit on top of the frame once I trimmed it. Then I sealed the seams with rv type roof sealer and then butyl tape over that then my friend made the alum channel to cover all the seams and corners.So far it's completley watertight. The floor is 5/8 plywood with 2" rigid insulation, the walls are 2x2 frame which is really 1 1/2 and 1/4 good ply outer and 3/8 rough ply inside covered with grey indoor/outdoor carpet from Home Depot. The walls have 1 1/2 rigid insulation. The door came from an old motor home and I gutted it and cut down and reused the aluminum frame. The windows are whats called jalousie style, some from e bay and a couple from a local guy. The rears were a gift from a neighbor. The roof is roughed in for a fan or vent but so far it,s not needed.