How do I help a customer picture how big a 30x40 or 40x60 metal building really is?
Short answer. Stop describing it and show it, and start from what goes inside rather than from the footprint. Ask what has to fit, how tall the tallest thing is, what has to drive through the wall and what gets added in five years; those four answers decide width, eave height, door sizes and whether the bay spacing has to change. Machinae Build draws the result: the customer types "40x60 shop, 16 ft eave, two 12 ft roll-ups" and gets a 3D building in about a minute, so the proportions are seen rather than imagined. It is a design and a code check, not a permit set, and every building still needs a licensed engineer's stamp for its county.
The four questions that decide the size
- What has to fit, and with how much room around it? Vehicles, equipment, benches, racking, a lift bay — with the walking room between them, which is what buyers leave out.
- How tall is the tallest thing, plus what it does? A lift needs the arm's travel above the vehicle; a stacked pallet needs the forklift mast at full extension.
- What drives through the wall? The opening has to clear the widest and the tallest thing that uses it, and the standard sizes below are the ones that come without a custom framing conversation.
- What is added in five years? A lean-to, another bay, a mezzanine. Length is the cheapest dimension to add later; width and eave height are the expensive ones to get wrong.
The standard sizes those answers land on
| Element | Standard size | What it is for |
|---|---|---|
| Walk door | 3 ft x 7 ft (3070) | Self-framing, so no framed opening is required |
| Roll-up door | 10 ft x 10 ft or 12 ft x 12 ft | The two sizes most buildings are detailed around |
| Dock door | 9 ft x 10 ft, 12 ft minimum centres | Fits 53-ft trailers and forklifts; step up to 10x10 for cold storage or a tight yard |
| Any opening 16 ft wide or wider | Engineered header | Drives column sizing and foundation anchors — coordinate before the slab is poured |
| Opening to corner or eave | 2 ft clearance | Framing, insulation continuity and weather-tightness |
Where the width stops being a free choice
Clear span decides the structural system, and the system decides what the building costs to build. Tube steel covers about 40 ft of clear span typically and 60 ft at the practical limit, with eaves to 16 ft. Cold-formed steel truss covers about 50 ft typically and 70 ft practically, with eaves to 26 ft. Above that it is red-iron PEMB, which is a different price of building. A customer choosing between a 40x60 and a 50x80 is often choosing between two systems without knowing it, which is why the system here is routed from the span rather than offered as a dropdown.
What showing the building does not settle
- It is not a permit set and it carries no engineer's stamp; the county's adopted loads still govern the final design.
- It does not price the building. The output is a neutral quantity schedule, never a dollar figure.
- It does not invent site loads. Ground snow, design wind and the climate zone are asked for, and where the site is unknown the product says the value is unknown rather than filling in a plausible number.
- It is not a site plan. Setbacks, easements, driveways and turning circles are not modelled.
Related
- Try it on a real size: design a building — five designs are free with no account.
- Put it on your own site for customers: machinaebuild.com/for-builders
- What one description actually generates: the outputs, in full