30x70 Barndominium

This page is ordered around zoning across the 30-foot span, because that is the dimension a barndominium cannot change later.

The footprint holds 8 living zones — 2 across by 4 deep — and leaves 8 feet of depth for a mud-room strip between the shop door and the living side, which is what stops the working half arriving in the kitchen.

Read this footprint through its span. 30 feet across is the fixed constraint; 70 feet of length is the negotiable one, and at 2.33 to 1 the building is long for its width, so movement runs front to back. Noise from this floor reaches the office, the neighbours and the yard, and separation is a plan decision.

A 30 by 70 footprint is a long corridor of a plan: 2,100 sq ft enclosed by 200 ft of wall, at a 2.3:1 length-to-width proportion. Along its 70 ft dimension it takes 5 runs of living zones at 14 ft, leaving 0 ft over — the 0 ft is where the argument about this size actually happens. When living space takes the greater share, the building is a house that happens to have a tall bay on one end. The planning consequence is that the residential side sets the window line, the ceiling heights and the entrance, and the working bay has to accept whatever the dwelling leaves. Two sides of the same shell rarely want the same temperature, and planning them as one zone is what makes running costs high.

This footprint is planned as a dwelling with a working bay attached rather than a shop with rooms in it. Compared with a 30 by 50 of the same width, the extra depth here adds run rather than reach: it buys about 5 living zones in line, and every position past the second is retrieved by moving what stands in front of it. Spent as a square 46 by 46 instead, the same 2,100 sq ft would stand 3 living zones across rather than 2, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. At this scale the building is usually operated by one or two people who know where everything is, so the plan can be loose and the doors matter more than the divisions. The longest internal travel on a 30 by 70 plan is about 76 ft corner to corner, and the shortest useful one is the 30 ft cross-run. For a a dwelling with a working bay attached rather than a shop with rooms in it that matters where living-dominant barndominium sits, because shortening the 30 ft run to serve it lengthens every trip along the 70 ft dimension. Two sides of the same shell rarely want the same temperature, and planning them as one zone is what makes running costs high.

The living-and-working balance this footprint could equally be planned around is a wide plan where separation is achieved by a buffer zone rather than a single wall: there is no middle band, so living and working spaces share a wall and every noise and temperature difference sits on it. Bedrooms and bathrooms take the quiet end, living and kitchen take the middle where the daylight is, and the working bay takes the end nearest the drive. Fitting the bay in the middle is the arrangement that most often fails, because it splits the dwelling in two.

The 8-foot leftover depth is 240 square feet across the full width — deep enough to plan deliberately, and at this footprint it goes to a mud-room strip between the shop door and the living side, which is what stops the working half arriving in the kitchen. Temperature swing on a steel shell drives condensation decisions that outrank most layout preferences.

Spare width is the more valuable of the two leftovers here: a continuous 6-foot strip beats the same area stranded at the end of the run, because it touches every position along the way. The count of working positions, not the headline area, is the figure that survives contact with the operation.

Compared with a 30 by 50 of the same width, the extra depth here adds run rather than reach: it buys about 5 living zones in line, and every position past the second is retrieved by moving what stands in front of it. Spent as a square 46 by 46 instead, the same 2,100 sq ft would stand 3 living zones across rather than 2, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. At this scale the building is usually operated by one or two people who know where everything is, so the plan can be loose and the doors matter more than the divisions. The longest internal travel on a 30 by 70 plan is about 76 ft corner to corner, and the shortest useful one is the 30 ft cross-run. For a a dwelling with a working bay attached rather than a shop with rooms in it that matters where living-dominant barndominium sits, because shortening the 30 ft run to serve it lengthens every trip along the 70 ft dimension. Two sides of the same shell rarely want the same temperature, and planning them as one zone is what makes running costs high. That movement pattern, not the 2,100-square-foot total, is what decides whether the leftover 8 feet is useful here.

The gable clears roughly 22 ft after corner framing: one opening, not two. At 4 ranks deep the useful pattern is end in, side out, using the 70-ft wall's 4 possible positions.

70 ft divides exactly into 5 bays at 14 ft. On 2,100 sq ft that grid is what keeps racking, doors and lighting from being set out three times.

70 ft is deep enough for 4 ranks and a zone behind them. 2,100 sq ft plans well as two zones with the split on a frame line.

2 living zones fit the 30-ft span with 6 ft to spare. Over 70 ft of run that slack becomes a continuous side aisle rather than 4 separate gaps.

This shape buys frontage with skin: 200 ft of perimeter for 2,100 sq ft, 95.2 ft per 1,000 sq ft, 9% above a square of the same area. At 2.3 to 1 that is the trade, not an error.

The 30-foot gable can carry 2 openings, one per living zone, with 6 feet of wall left for piers between and beside them — the arrangement that keeps each position independently reachable. Snow, wind and site exposure change what this shape costs to build long before the interior plan does.

The 30 ft ends and the 70 ft sides offer very different opening budgets: 30 ft of end wall has room for one wide opening or two modest ones, while 70 ft of side wall can carry several without the openings competing. On this plan the deciding factor is whether living-dominant barndominium or shop bay attached to a dwelling should be the first thing reached from the door.

Nominal bay division computes to 3 bays at about 23.3 feet, wider than the 12-foot module — so a position can sit inside a bay without a frame line splitting it. Access, not area, is what makes a plan feel small once it is in use.

With 4 rows deep, the rear row is behind the front one. Without a route past it, those living zones become storage positions rather than working ones — the real cost of depth at this width. Set the openings before the interior, because the openings cannot move and the interior can.

Extension is cheapest along the 70 ft dimension, where each added bay repeats work already framed; widening past 30 ft is a different frame rather than a longer one. Growing to 30 by 84 adds a 6th run of living zones — useful if the constraint is living zones rather than the 0 ft already spare at the far end.

Configured as a dwelling with a working bay attached rather than a shop with rooms in it, 30x70 is judged on whether the 8 living zones it holds match the operation, and on whether the 6 feet of spare width leaves the route this mode depends on.

• Does the work need two parked lanes side by side, or one lane and a genuine workbench run, or does it need a second lane that this 30-foot span cannot give?
• Is the 70-foot length being bought for depth, or for the repeated bays — six to eight repeated bays, and the bay line becomes the organising device for the whole plan?
• Where does the dividing wall sit, and what does the working half lose when it moves?
• Is there a loft, and has the frame been planned for it rather than around it?

Across a 30-foot span the 3:12 pitch adds 3.8 feet between eave and ridge. The centreline measures 17.8 feet; anything parked or stacked near a wall lives with the 14-foot eave. Where the building sits on the site changes how much of this floor is genuinely reachable.

The dwelling wants ordinary ceiling heights and the bay wants clearance, so the eave is chosen for the bay and the residential side takes a flat ceiling below it.

The living half is a conditioned envelope and the working half often is not, which makes the dividing plane the most important detail in the building.

• 24x36 moves the count from 8 to 2 living zones (2 across by 1 deep), which is the reason to choose between them.
• 30x30 moves the count from 8 to 2 living zones (2 across by 1 deep), which is the reason to choose between them.
• 20x45 moves the count from 8 to 1 living zones (1 across by 1 deep), which is the reason to choose between them.

Because this footprint is planned as a dwelling with a working bay attached rather than a shop with rooms in it, the useful next reads are different from the ones a differently shaped barndominium suggests: living-dominant barndominium, shop bay attached to a dwelling, boundary between house and shop.