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NEC 110.26 working space at the panel: 30" wide × 36" deep × 6'6" headroom, kept permanently clear. The 4-ft alley between the block wall and the shed passes with margin — the app flags red if you drag the shed closer than 3 ft while it covers the panel. Corridor stays open-air (pavers + optional lattice over top) so the meter stays "exterior" — call Duke Energy before ever enclosing the meter in walls.
Heartland Estate 10×10 gambrel — 7' sidewalls, 11' peak, 64" double door (drawn with swing arcs so you can see step-in room). Gutters belong on the two eave sides (the ridge runs toward the house, doors face the yard) — downspouts point away from the walkway. If you want the 2-person IR sauna, the same line comes in 10×12 — there's a size preset in ⚙ Site.
4" of 3000 psi, #3 rebar @ 18" o.c., 12"×12" thickened perimeter with 2×#5, 10-mil vapor barrier, termite pre-treat, wet-set ⅝" anchor bolts ≤4' o.c. Slope ~1% to a 2" floor drain near the spa. The slab card shows live square footage and concrete yardage as you resize.
Seminole County requires a permit for sheds — Heartland's Florida engineered drawings (~$650) are the permit packet + anchor schedule. Stay out of the recorded 7.5' utility easement on the rear (east) line — hatched red in the scene. Accessory setbacks are commonly ~5' from side/rear lines in residential districts but verify your zoning with the county — this is a single-frontage lot (Sandalwood Dr only; the north line backs to a neighbor's yard, not a second street), so no corner-lot street-side rules apply. This shed sits mid-lot near the house, well clear of all of it.
Spa cover stays on when idle; humidistat exhaust high + intake low; 9k BTU mini-split for June–Sept; the sauna is a self-contained 1-person IR cabin — the room itself never becomes the sauna.
Sources: your survey (Lot 54, Laurelwood, PB 15 PG 85 — 100'×75', 7.5' rear utility easement), tape photos, Heartland Estate 10×10 listing, prior concept set notes. Concept only — final design per FL-licensed engineer + Seminole County Building.