Shed Studio Plan

Key

Existing joists and outer frame

New joists in the 520 extension

3600 × 900 particleboard, 365 rip at the edge

Inner room frame, 600 c/c, 25 gap

Window and double slider, glass in each wall

Deck, 1500 deep, full length

Bass traps, side panels, cloud, rear panel above couch height

Speakers at the low end, mix position

Couch on the east wall, back on hard wall: 3-seater, or a 2-seater beside the kit

Drum corner: kit 1800 × 1600 on the south wall, drummer facing the deck

Assumptions

Outer walls 2400 at the low end, 2850 at the high end, above finished floor.
Build-up: 90 outer stud, 25 gap, 90 inner stud, two layers of 13 plasterboard.
Inner ceiling sits 260 below the outer top plate and follows the roof slope.
Sheet joins land on existing joists at 1730 and 3530; the perimeter bays can be any size.
Double slider 1800 × 2100 in both walls, two bypassing panels (no wall pockets), from 2600 to 4400 along the long side. Window 900 × 800, sill 1000, centred, leaving wall behind each speaker for treatment. Laminated glass of different thickness in each wall, for door and window alike.
Mix position 1670 from the inner front wall, about 38% of the room length.
Deck 1500 deep along the full door side, at floor level.
Rear (east) wall treatment starts at 950, so a couch back sits on hard wall below it; the corner traps carry the bass. The slider's west leaf is the one that opens.