1. Project overview

Convert an existing workshop room in the barn, approximately 24 ft × 16 ft with a concrete slab floor, into a 16 × 16 ft wine cellar, an 8 × 8 ft hardened walk-in gun vault, and an 8 × 8 ft unconditioned pass-through. The room is currently finished in OSB over framing with a painted, finished ceiling, a bank of vinyl windows on one long wall, glazed French double doors as the main entry, a second set of glazed French doors into the barn's main area, a solid door to an adjacent room, a utility sink (existing plumbing and drain), a ductless mini-split head, and surface-mounted LED shop lighting. The vault is a ~8 × 8 ft room incorporating the 63″ × 41″ alcove as a recessed display bay, with a single opening (the vault door) off the pass-through; the adjacent-room door opens into the pass-through and stays in service unchanged.

Assumptions to verify on site before pricing: overall dimensions and ceiling height (assumed 9 ft), slab thickness and condition, framing size in existing exterior walls, electrical panel capacity and location, and whether the existing mini-split head can be relocated. All dimensions in this document should be treated as nominal until field-verified.

1.1 Openings schedule

The utility sink should be preserved (in or accessible from the pass-through if possible) — it provides the condensate drain for the cellar cooling unit and a cleanup point for the shop functions that remain.

2. Layout

Plan view, nominal dimensions. Wall thicknesses not to scale.

The new partition wall runs across the 16 ft dimension, 16 ft from the entry wall (the end wall with the French doors), and the far third is split in two: a hardened gun vault of roughly 8 × 8 ft that incorporates the existing 63″ × 41″ alcove as a recessed bay, and an unconditioned pass-through on the remainder. The wine cellar's entry is the rebuilt French-door opening. The vault has a single opening — the vault door, entered from the pass-through. The alcove becomes the long-gun display bay, and the door to the adjacent room opens into the pass-through, remaining in service unchanged. The glazed French doors to the barn's main area sit in the cellar's window wall and are rebuilt insulated like the entry pair, staying usable. The pass-through keeps the existing door to the adjacent room, is reached through a new insulated man door from the cellar, and hosts the cleaning table, keeping solvent fumes out of the sealed room entirely. The window bank falls within the cellar zone and is permanently sealed with insulated infill panels. The cellar perimeter carries storage racking on three walls plus a label-forward display wall on the cellar side of the partition, for a planning capacity of roughly 770 bottles including the center island.

3. Wine cellar specification

3.1 Envelope and insulation

The cellar will operate at approximately 55 °F and 60 % relative humidity year-round, so the envelope must be treated like a walk-in cooler. All cellar-facing walls and the ceiling receive closed-cell spray polyurethane foam to a minimum of R-22 in the walls and R-32 in the ceiling (approximately 3–5 in of closed-cell foam, which also serves as the vapor retarder). Where rigid board is substituted, a dedicated 6-mil poly vapor barrier must be installed on the warm side of the assembly with sealed seams. The interior finish should be moisture-tolerant: cement board or green board with mold-resistant paint, or clear-sealed wood paneling.

The window bank within the cellar zone is to be sealed from the interior with rigid-foam infill panels (minimum R-10), airtight and finished to match the interior; exterior glazing may remain for appearance. The glazed French double doors at the entry are replaced or retrofitted per the openings schedule (section 1.1) — insulated, fully weatherstripped, threshold sweep, and no exposed glazing on the cellar side.

3.2 Cooling

Room volume is approximately 2,300 cu ft (16 × 16 × 9 ft). The existing mini-split is not suitable for cellar duty — it cannot hold 55 °F reliably and strips humidity. Specify a dedicated wine cellar cooling unit sized for 2,000–2,500 cu ft with exterior heat rejection. Two acceptable approaches: a self-contained through-wall unit venting directly through an exterior wall (WhisperKOOL SC PRO 2000 class, approximately $2,100–2,600 for the unit), or a ducted self-contained/split system with the condenser outside for silent operation (CellarPro ducted class, approximately $3,300–6,500 installed). The through-wall option is simpler and serviceable; the ducted option is preferred if noise matters. Either way, provide a condensate drain — the existing utility sink drain is the natural tie-in — and a dedicated circuit.

3.3 Racking

Perimeter racking as drawn: full-height racking (approximately 7.5 ft) along the 16 ft rear wall (~260 bottles), counter-height racking beneath the sealed windows (~120 bottles), full-height racking on the entry wall segments (~150 bottles), and a label-forward display wall on the partition (~90 bottles). Planning total is approximately 620 bottles with room to densify later. Budget guidance: modular pine or metal racking runs roughly $20–60 per bottle installed; label-forward display and custom millwork run $80–250+ per bottle. A modular system with one feature display wall is the cost-effective middle path.

Center island: a freestanding island of approximately 78 × 30 in, waist height, with diamond bins and case slots below (~120–170 bottles) and a durable tasting and decanting top — stone remnant or sealed hardwood. Keep 42–48 in of clearance on all sides for racking access. It fills the otherwise dead center of the room, adds roughly 150 bottles of bulk storage (planning total ~770), and gives the cellar a work surface so bottles never get staged on racking. Optional refinements: a shallow drawer for openers and preservation gear, and a lower shelf for wooden cases.

3.4 Electrical and lighting

Low-heat sealed LED fixtures on a dimmer, switched at the door. One dedicated 20 A circuit for the cooling unit, one convenience receptacle (interior-rated, gasketed), plus a receptacle at the island location for the serving fridge (section 3.5). No recessed cans penetrating the insulated ceiling unless fully sealed IC-rated fixtures are used. Rough in the display and island lighting (below) with the rest of the electrical — it is trivial during framing and expensive after.

3.5 Enhancements

Large-format shelf: a single deep shelf above the entry door (or along the top of the rear wall) sized for magnums and 3 L bottles, which do not fit standard racking. Dual-zone serving fridge: a small glass-front unit built into the island or rear wall run, holding a case or two of whites and sparkling at ~45 °F serving temperature — the cellar's 55 °F is storage, not serving, temperature; requires the island receptacle above. Display lighting: low-heat LED strip lighting on the label-forward display wall and under the island counter lip, dimmer-controlled with the room lights. Inventory board: slate or chalkboard panel beside the door for bin locations and drink-by notes. Seating: two backless stools tucked under the island overhang for tastings — they stay clear of the 42–48 in racking aisles.

4. Gun vault room specification

4.1 Hardened shell — the room is the safe

All six sides of the 8 × 8 ft room are hardened; there is no freestanding safe. Two new hardened walls: the vault's share of the cellar partition, and the wall between vault and pass-through carrying the vault door — both 2 × 6 studs at 16 in o.c., sheathed both sides with 3/4 in plywood, plus 10-gauge steel plate (or welded expanded-steel mesh as a value alternative) on the vault side, cavities filled with mineral wool, finished with fire-rated 5/8 in drywall. The two existing framed exterior walls within the vault zone receive the same treatment from the interior: 3/4 in plywood plus steel plate or mesh over the existing framing, mineral wool where cavities are open, fire-rated drywall finish. The ceiling is the classic weak point and must be hardened to the same standard as the walls — plywood plus steel plate or mesh fastened through to the framing, finished with fire-rated drywall. The concrete slab requires no reinforcement. The alcove's three walls and ceiling are hardened to the same standard as the rest of the shell. The smaller footprint roughly halves the hardening area versus the earlier 8 × 16 scheme.

Fasteners matter: steel and plywood layers should be through-bolted or screwed on a tight pattern from the protected side, with seams staggered between layers so no continuous joint exists through the assembly.

4.2 Vault door

Specify a residential out-swing vault door, nominal 80 × 30–36 in, plate-steel construction with a UL-listed Group 2 or better lock, internal release, and a day latch (AMSEC VD8030BF class, or a Smith Security Safes custom door). Standard residential vault doors run approximately $1,900–4,000; heavier commercial-grade doors run $4,000–12,000. Budget $3,500–8,000 installed including the reinforced rough opening and frame grouting or through-bolting. The door frame must tie into the hardened partition assembly, not just the studs.

4.2a Pass-through zone

The 8 × 8 ft pass-through between the vault and the cellar partition stays unconditioned and unhardened — it is circulation and work space, not secure space. It keeps the existing door to the adjacent room unchanged, is reached through the new insulated man door from the cellar (exterior-rated, weatherstripped, matching the entry spec), and hosts the vault door into the vault. The freestanding cleaning table lives here with GFCI receptacles and a work light, which keeps solvents and fumes outside the sealed vault. Because every vault approach now passes through this room, it is the natural place for a camera or motion sensor if the property is monitored.

4.3 Climate and humidity control

Target 30–50 % relative humidity (NRA guidance for firearm storage) and stable temperature. Relocate the existing mini-split head into the vault room for temperature control, and add a dedicated compressor-type room dehumidifier with a built-in humidistat and a condensate drain or pump (BaseAire or equivalent, approximately $250–1,000). The hardened, insulated partition doubles as the thermal break against the 55 °F cellar next door. Install a simple digital hygrometer; a WiFi model with alerting is a cheap safeguard.

4.4 Fittings

End wall: floor-to-ceiling long-gun display and storage system (SecureIt or Hold Up Displays class, slat-wall or CradleGrid type) sized for the collection. Opposite wall: pistol display panels above locking base cabinets for ammunition and accessories. The cleaning and maintenance workbench moves to the pass-through (section 4.2a), which frees the vault floor and keeps solvent fumes out of the sealed room — so the vault itself needs only sealed LED lighting, wall receptacles, and a passive transfer grille with baffle for air exchange.

5. Items for the contractor to confirm

Field-verify room dimensions and ceiling height. Locate the glazed barn-area door against the planned cellar/pass-through split and apply the matching treatment from the openings schedule (section 1.1) — shift the vault/pass-through split if needed so it never lands in the vault. Confirm the utility sink location and drain routing for the cooling-unit condensate. Confirm framing layout for the two new walls (cellar partition and vault/pass-through wall) and the rough opening for the new insulated cellar door. Confirm electrical panel capacity for two new dedicated circuits and the relocated mini-split. Confirm the exterior wall selected for the cellar cooling unit's heat rejection has clear exterior space. Confirm slab condition where the vault door frame anchors. Check local permit requirements for the partition, electrical work, and mechanical work. Confirm door swing clearances at the existing entry once the insulated door is specified. Finally, confirm the insurer is notified — a documented vault room and conditioned cellar can matter for coverage of the contents.