How much does a slab for a metal building cost?
Slab prices for the metal building sizes people ask about most, from the same engine that prices the building. Area is the building footprint; each price includes the default 15% markup.
Prices as of September 2026.
Slab cost by building size
| Building | Slab area | Rate | Slab cost | Per sq ft |
|---|---|---|---|---|
| 30' × 40' | 1,200 sq ft | $13.00/sqft | $17,940 | $14.95 |
| 40' × 60' | 2,400 sq ft | $13.00/sqft | $35,880 | $14.95 |
| 50' × 100' | 5,000 sq ft | $11.70/sqft | $67,275 | $13.46 |
| 60' × 100' | 6,000 sq ft | $11.70/sqft | $80,730 | $13.46 |
Why bigger slabs cost less per square foot
The app starts from a base rate of $13.00 per square foot. Slabs under 1,000 sq ft pay 20% more, because mobilizing a crew and a pump costs about the same whatever the size. Slabs over 3,000 sq ft get 10% off. Every rate and threshold is yours to change in Settings.
What moves a real slab price
- Thickness and rebar: these prices are for a standard shop slab; a thicker slab for heavy equipment costs more
- A brick ledge or a thickened edge around the perimeter
- Lean-tos and gable extensions you want poured, which the app adds to the slab area
- Site prep and pad: not included, and often the biggest unknown
Span charts behind these sizes
The highlighted rows set this building's sizes: a 40' clear span calls for W12x19 frames, and 30' bays call for 10" roof purlins. These are the app's default charts.
Main frame · gable
| Clear span up to | Beam |
|---|---|
| 30' | W12x14 |
| 40' | W12x19 |
| 50' | W16x26 |
| 60' | W18x35 |
Purlins & wall girts
| Bay span up to | C-section |
|---|---|
| 20' | 6" |
| 25' | 8" |
| 30' | 10" (roof only) |
Adjust them for your climate. Snow and wind loads vary by region, so every row is editable on the app's Settings tab. Change a size or a span break to match what your engineer or local code requires, and every new estimate uses your charts. More about span charts
Price the slab with the building
In the app, the slab comes from the same drawing as the steel: add a lean-to on slab and its footprint is added automatically. Concrete pricing is part of the Pro plans.
See it before you order it
This same 40x60 draws itself in the app. Pick your wall, roof, trim, door, and wainscot colors and the building repaints in 3D; switch to the wireframe to check where the purlins, girts, eave struts, and jamb purlins land. Eight views — four isometric corners and four straight-on elevations — so you can look at a door from outside or the framing from the corner you'll erect from.
Change any dimension and get your own real takeoff.