Assembling the Floor
For the floor of the shelter I used 18″x18″ x1½” thick pavers resting on washed sand. Here is what the final result looks like:
Leveling the floor was pretty straight forward. I filled as much of the original sand back in the hole I had dug to install the cement borders. I then bought a couple of bags of washed sand and filled that on top of the original sand to install the pavers. I made a template that spanned the width of the side cement borders. On this 2×4 I nailed a 1½” thick wood board which had the same thickness as the pavers. I then passed this template back and forth over the sand, using the top of the side cement borders as a datum, to create an equal thickness gap equivalent to the thickness of the pavers. When the sand was all smooth and level I simply positioned the pavers on top of the sand.
As the pictures show, a 1½” gap was left on either side of the pavers. I could have cut a few pavers to a width of 3″ to fill that gap but decided, instead, to place two, 1½” x 1½” x 1/8″ thick square aluminium tubular extrusions to fill the gap. My intent is to feed electrical wiring through at least one of these, creating kind of a long “power bar” to bring power to the telescope without apparent wires resting on the floor. It will make for a much neeter arrangement.
I made two mistakes during this part of the project. First, I used washed sand. I quickly found out in the spring that ants LOVE this sand. I seem to have generated quite a colony under the floor and I will have to replace the sand with something less inviting to the little guests. Next spring I plan on replacing the sand with rock dust which is what is usually used for this type of landscaping work.
The second mistake was to not be sufficiently carefeul of squaring the foundation cement borders when I was assembling them. I was very concentrated on keeping everything level but when I back filled the soil I didn’t notice the borders were not quite layed out in a square pattern. There is a lack of perpendicularity of about 1″ over the 8 feet long section where the cover rests. I noticed the error only when laying out the pavers. I didn’t have the courage to tear everything out and re-adjust. See here how I compensated for this mistake.