All lengths in inches. Counted off the 3D model.
Framing
| Member | Size | Length | Qty | Cut from | Notes |
|---|---|---|---|---|---|
| Joists | 2x8 PT | 117″ | 9 | 2x8 x 10' | Face-mount hangers, tops flush at +10.75" |
| Skirtboard, two sides | 2x10 PT | 120″ | 2 | 2x10 x 10' | — |
| Skirtboard, other two | 2x10 PT | 117″ | 2 | 2x10 x 10' | — |
| Posts | 4x4 PT | ~11 | 8 | 4x4 x 8' | CUT INDIVIDUALLY after all blocks are leveled |
| Pier blocking | 2x8 PT | 14.5″ | 2 | 2x8 x 8' | Bay Y 44-60, centered X 44 and X 60 |
| Ring blocking | 2x8 PT | 14.5″ | 10 | 2x8 x 8' | Where the 88" circle crosses each joist bay — NOT on grid lines |
| Bay blocking | 2x8 PT | 14.5″ | 2 | 2x8 x 8' | X 34 and X 70, bay Y 92-108 |
| Bay blocking, short | 2x8 PT | 8.25″ | 2 | 2x8 offcut | X 34 and X 70, bay Y 108-117.75 |
| Decking | 5/4 x 6 PT | 120″ | 21 | 5/4 x 6 x 10' | Crown up, cup hollow-side DOWN, 1/8" gaps |
| Hatch boards | 5/4 x 6 PT | 17.5″ | 5 | decking offcut | Cut from the field after decking over the opening |
Pier
| Member | Size | Length | Qty | Cut from | Notes |
|---|---|---|---|---|---|
| Rebar verticals | #4 (1/2") | 70″ | 4 | #4 x 10' | 3" clear at bottom, ~4" below pour line at top. 50" offcut each. |
| Rebar ties | #3 (3/8") | 5″ | 12 | #3 bar, 60" total (one 4' bar is 12" short) | 4 per level, 3 levels, below grade only. Straight — no bending. |
| Footing cross ties | #4 offcut | 11″ | 2 | vertical offcut | Flat in the footing, 3" up. Optional. |
| Form tube | 12" dia | to the height mark | 1 | 12" x 48" tube | CUT IN PLACE off a level line from the joist tops. Rim = screed line. |
| Threaded rods | 1/2"-13 | 36″ | 4 | stock 36" | ~31" embedded, ~5" projecting, 27" lap with the cage |
| Tube spacers | 2" OD x .25 wall | = chosen gap | 4 | steel tube | Ends faced square. Test the gap with a wrench in hand BEFORE cutting. |
Before you cut
- Test the adapter gap on the bench with a hand and wrench before cutting spacers — the gap is the free variable, and the pour height follows from it.
- Measure the assembled adapter height, then: concrete_top_above_floor = 34.5 - adapter_height.
- Cut the form in place off a level line from the joist tops, not to a computed length from grade — grade is not flat.
The two that bite
Posts. Never pre-cut all eight. If one block sits 1/8" low, that post gets 1/8" more, and the skirtboard still lands at 10-3/4" everywhere.
Ring blocking. The ten positions are where the 88" circle crosses each joist bay, not a convenient grid. The dome's load arrives as a line around that circle. Blocking anywhere else carries nothing.