Physical Structure

This is the detailed measurement and physics reference behind The Greenhouse. Start with the overview page for the human-scale tour, then use this page for dimensions, glazing, airflow, thermal envelope, and solar geometry. Live visual context is available on Greenhouse Cameras.

Dimensions & Shape

Interior dimensions below are direct tape measurements from April 2026, generally precise to ±0.5”. Orientation and elevation are supported by map/satellite measurements and are treated as canonical constants for solar-angle reasoning until a future survey replaces them.

Measurement Model

To avoid mixing unlike measurements, this page distinguishes between:

• Interior usable geometry — tape-measured floor dimensions used for crop area, equipment layout, and air volume

• Exterior/remote geometry — map or satellite-derived measurements used for orientation, footprint context, and future sun-angle analysis Current canonical values:

• Interior usable floor area: ~367 sq ft

• Interior air volume: ~3,614 cu ft

• Exterior footprint: likely larger than interior usable area and still subject to refinement

• Long-axis heading: 156.49° for solar and orientation calculations

Floor Plan

Functional Layout Implications

The geometry of the greenhouse forces a very specific operational layout. It is fundamentally a long, narrow rectangle (~2:1 aspect ratio) with a shallow convex bump at the south end. The hexagonal taper only accounts for about 17% of the total length and adds just 61 sq ft. That shape dictates how the space is actually used:

• The West Wall: The single most productive surface in the building. It offers 22+ linear feet of uninterrupted shelf space and overhead grow light coverage.
• The East Wall: Highly productive but broken up. It is split between the patio door (the primary summer intake vent) and the hydroponic infrastructure.
• The North Wall: Entirely sacrificed to mechanical systems and the house connection. The mismatch between the 25.5” perimeter pony wall and the 49” north wall shelf highlights its different construction character. It acts as a massive thermal bridge and passive buffer, but cannot be treated as glazed growing surface.
• The South End: The hottest and brightest zone, but physically the most constrained. The angled SW and SE faces each carry one high-mounted exhaust fan, while the 85” center face remains a narrow end cap between them. Because the fans are on angled faces (~30° apart), the exhaust exits at two different angles, creating a wider effective exhaust cone than a single flat plane would. This is better for pulling air from across the full greenhouse width, but neither fan points straight down the long axis — the exhaust path has a slight lateral bias depending on which fan is dominant. Despite its prime solar exposure, the south end functions heavily as an exhaust and thermal-stress zone.

Airflow & Volume Implications

The peaked roof with its 35” rise above the wall line creates a surprisingly generous volume (3,614 cu ft) for a 367 sq ft footprint. That vertical space is doing real work for heat stratification and airflow. The clean conceptual airflow story is north vent → center → south exhaust. But the real summer airflow path is messier. Once the patio door is open or screened, the dominant intake becomes the east / northeast side, creating an asymmetric east/NE → south diagonal wash rather than a true north-to-south sweep. That helps explain why the west wall still runs hot even with aggressive exhaust. The center zone acts as a pass-through and humidity pivot point. The fog machine conditions moving air, but because it sits in the middle of the room instead of directly at the intake plane, it is not acting as a true intake-side evaporative cooler. HAF (horizontal air flow) circulation fans, on the order of ~700-800 CFM total, would likely improve temperature mixing substantially and reduce internal zone differences.

Wall Dimensions

Structural Framing

Glazing

All primary greenhouse glazing surfaces are Gallina PoliCarb 2P — 6mm twin-wall polycarbonate with an opal (frosted) finish, installed December 2023. The patio door includes a removable glass insert, but the growing envelope is polycarbonate. The opal finish diffuses incoming light, so plants receive softened light rather than a clean direct beam.

Doors

Orientation & Solar Geometry

The greenhouse is not aligned to perfect north-south. Its long axis runs at a measured heading of 156.49°, which is roughly NNW to SSE, with the west side facing WSW and the east side facing ENE. That matters for how solar load actually arrives:

• morning light enters from the ENE side but is heavily modified by the east-side tree
• the WSW-facing wall takes late-day heat harder than a due-west simplification would suggest
• the faceted south end spreads midday solar across multiple faces instead of one flat wall
• future sun-angle, shade-cloth, and seasonal transmission analysis should use this 156.49° rotated geometry, not a perfect cardinal assumption

These constants are the export baseline for public diagrams, simulation notes, and future structure data files: interior usable area, air volume, long-axis heading, wall lengths, polycarbonate envelope, and altitude should stay consistent across pages.

Surroundings

Thermal Envelope

Glazed Area Breakdown

Live Light Transmission

The hexagonal shape creates a daily signature — transmission peaks when the southwest face catches afternoon sun, and drops when the east tree blocks morning light.

Floor

The concrete slab is a thermal battery. South zone stays 2–4°F warmer overnight from stored solar heat. On moderate nights (50°F+ outdoor), the slab’s retained heat plus poly insulation plus house connection mean the greenhouse holds above 67°F without any heater assistance.

Interior Equipment Layout

North Wall (Equipment Zone)

No planting. The 49” shelf spans the full width as an equipment staging surface.

• House door: west side of wall, standard interior door, always closed
• Stainless steel sink: centered on wall, with faucet
• Irrigation/sprinkler manifold: mounted above sink — horizontal header pipe with 8 vertical drops and 4 solenoid valves controlling clean and fertigation water paths to south, west, and center zones
• ESP32 controller: Kincony KC868-E16P (ESPHome firmware), west side, mid-height
• Four SSR relay boxes: CG SSR-25DA (DC→AC, 25A), spaced along wall near ceiling
• Intake vent: 24×24” (4 sq ft opening), mechanical actuator with insect screen, centered horizontally, mounted high near roofline. Controlled by ESP32 economizer logic — opens when outdoor enthalpy is lower than indoor.
• Copper irrigation piping: runs from manifold to distribution points throughout greenhouse

East Wall

• Patio door: 33” wide glass/screen combo, starts 32” from NE corner
• Wire shelving: between patio door and workbench (seedling trays, propagation flats)
• Workbench: south of patio door area, marks boundary before hydro begins
• Hydroponic NFT system: 3× 4” PVC rails (A, B, C), each with top and bottom row, 60 total positions. Grodan rockwool in net cups with clay pellets. General Hydroponics Flora/Bloom/Grow nutrients. Recirculating pump.
• Hydro reservoir tank: floor level below rails, near north end of hydro run
• 14× Barrina 2FT LED grow lights: mounted above hydro at ~12” on-center spacing

West Wall

• 6 shelf bays: evenly spaced along full 22’5” wall, each with top tier (~4.5’) and bottom tier (~2.5’), wire shelving uprights
• 15× Barrina 2FT LED grow lights (24W each, CRI 80): shelf-level, ~2–3 per bay
• 15× Barrina 4FT LED grow lights (42W each, CRI 98): mounted on rafters overhead at 36” on-center spacing
• 3 overhead mister heads: evenly spaced along wall

Southwest Face

• 1× KEN BROWN 18” shutter exhaust fan (2,450 CFM, 52W): high-mounted
• 2 shelf bays (top and bottom tiers), angled to match wall face

Southeast Face

• 1× KEN BROWN 18” shutter exhaust fan (2,450 CFM, 52W): high-mounted
• 2 shelf bays (top and bottom tiers), angled to match wall face

South Center Face (End Cap)

• Narrow face between the two exhaust fan walls
• Wall-mounted mister nozzles (part of south zone’s 6 heads / 30 nozzles)

South Zone Floor

• Floor pots centered in hex taper (established canna lilies)

Ceiling-Hung Equipment

Both major HVAC units are suspended from the trusses, not floor-standing or wall-mounted. They occupy the vertical band between the truss bottom (96”) and approximately 18” below it — the same zone where the 4FT overhead grow lights and relay boxes live.

• Lennox LF24-75A-5 gas furnace (75,000 BTU): ceiling-hung from trusses via metal straps, approximately 6’ from north wall, with flue pipe rising through roof
• AquaFog XE 2000 HumidiFan (1,644W): ceiling-hung from trusses via metal straps, approximately 5’ from north wall, output nozzle oriented to blow N→S along the greenhouse long axis

Mister Distribution

Sensor Placement

Vertical Zone Map

Annotated Floor Plan

Where to Go Next

• Equipment — relay maps, sensors, and controller hardware
• All Zones — climate profiles and planting for each zone
• Climate at 5,000 Feet — how altitude and arid air shape the control problem

This physical envelope is why the climate control problem is what it is.