Barn Jig

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Study the proportions of a barn with every dimension on a slider — length, width, wall height, bays, joist + truss spacing, a 2nd floor, ridge height and its offset from centre, the two roof slopes, and overhangs on all four sides. The drawings (axon, gable section, plan) redraw live, and a material readout answers alongside: areas and volume, framing lineal feet, and honest 4'×8' sheet counts with the waste each surface leaves. Two roof modes make it a real jig: drive the ridge and read the slopes, or drive the slopes and read the ridge. Client-side.

Length

Width

Wall (eave) height

2nd floor height (0 = none)

Ridge height

Ridge offset from centre

Left roof pitch (derived)

Right roof pitch (derived)

Bay spacing (3 bays)

Truss spacing

Joist spacing

Eave overhang — left

Eave overhang — right

Rake overhang — front gable

Rake overhang — back gable

Windows — eave walls

Window width

Window height

Sill height

Window offset from bay centre

Skylights — roof planes

Skylight width (along ridge)

Skylight length (up slope)

Skylight offset from bay centre

Up-slope shift (+ toward ridge)

One per structural bay, centred on the bay plus your offset. Anything that doesn't fit its bay, wall or slope is shrunk to fit (6″ frame margins) — the readouts above show the size actually drawn.

Sync at the top of the page hands this barn to Eco-Architect (sun, wind and goals), Assayer (carbon and forces), Conjure (editable build() program) or Acoustician (reverberation and room modes). Structure — bays, trusses, sheets — stays here.

Proportions

Plan (L : W)1.50 : 1

Width : ridge height1.33 : 1

Eave : ridge0.56 : 1

Roof pitches8:12 · 8:12

Area & volume

Footprint864sf

Loft floor864sf

Total floor area1,728sf

Wall area (4 walls)1,392sf

Roof surface (true)1,233sf

Roof plan (footprint)1,026sf

Envelope (walls + roof)2,625sf

Volume12,096cf

— below loft6,912cf

Envelope / volume0.217sf/cf

Openings

Windows (6)4' × 3'sill 3'-6"

— window area72sf

Skylights (6)3' × 4'

— skylight area72sf

Glazing / envelope5.5%

One per bay, centred on the bay plus your offset; skylight area is measured on the slope. Wall/roof areas, framing and sheet counts above stay GROSS — openings are not deducted (no headers, no trimmers counted).

Framing (lineal ft)

Member	n	each	lf
Posts	8	10'	80
Roof trusses	10	56'-5"	564
Loft joists	28	24'	672
Ridge	1	38'	38
Plates & sills	4	60'	240
Total			1,594

Study quantities — members at spacing, truss = chords only (no webs), no openings or laps. For comparing proportions, not ordering lumber.

Plywood — 4×8 sheets

Surface	sf	sheets	waste
Eave walls (×2)	720	30	25%
Gable walls (×2)	672	26	19%
Roof — left plane	617	25	23%
Roof — right plane	617	25	23%
Loft floor	864	27	0%
Total	3,489	133	18%

Counted by laying a real 4'×8' grid over each surface (best of the two orientations) — every touched cell is a sheet, offcuts are not re-used. Waste = sheets × 32 sf − net area. Roof + gables count both planes/walls.