I think I see your situation. First, you intended to have a flush fit deck board within the external base frame structure, yes? I assume this based on the post. You have even notched out the corners. If your internal supports are the same height as your external base frame box and it's glued and screwed together, you're going to have to change gears. I would just make a new deck board and have it fit on top of the entire frame so that the external edges sit on top of the external frame. This is how I did my roof and it worked well.
If memory serves me right, you wanted more of a Met Police box anyway. I think most of them did not have a chamfer that was more of a TARDISy thing. My recent trip we had this discussion. KB's build has no chamfer on the base frame. His deck board is flush with his base frame, very nice and supportive way to go.
Right then, I am off to bed. I am feeling the jet lag setting in.
Last Edit: May 22, 2009 3:10:09 GMT 1 by DOCTOR IZ
The base is now complete and I decided to start again with the floor section. The floor section now sits on top of the frame rather than inside the frame as the plywood sheet couldnt take the weight of the planks inside the frame. The plywood sheet is now screwed on top of the frame.
That base look fantastic! Now you're cooking with oil mate! Keep up the good work. How are you mounting the corner posts to the base? Is the build going to permanently assembled once it's complete or detachable?
Jon thanks very much it sure is good to know that I am on the right track with my build. My box will be a permanent structure for my garden. What I intend to do is mount all 4 corner posts with my L brackets on the base just to see how well they fit. But when I permanently mount them they will be with bolts. The next 2 corner posts are already being built.