Metal building foundations and slabs

What a metal building slab has to match

We lay the slab out to the building's plans: the length, the width, the diagonals checked square, and any door openings or interior columns marked before the forms go up.

Getting that layout right matters more here than on most slabs. A wood-framed building can be trimmed and shimmed on site to fit a pad that's a little off, but a steel building arrives pre-cut and pre-punched, so the pad has to match it.

Two buildings with the same footprint can need different pads when their frames and anchor points land in different places. That's why we work from the manufacturer's drawings.

Setting anchors where the building's drawings call for them

The manufacturer's engineered drawings specify exactly where each anchor bolt needs to sit, tied to the building's frame and column layout. Those bolt locations get set into the slab while it's poured, using a template or careful layout from the drawings.

Checking the anchor layout against the drawings before the pour catches problems early: it's a lot easier to catch a mismatch on paper than to fix one after the concrete's cured.

A thicker edge where the walls and anchors sit

Most metal building slabs are poured thicker around the perimeter than in the middle, since that's where the wall panels, the anchors and the building's frame load concentrate. A thickened edge spreads that load out over more concrete and more soil instead of relying on a uniform slab thickness to carry it everywhere.

A larger building, or one with interior columns, may need thickened sections in the middle too, wherever the frame comes down to meet the slab.

How long does a metal building pad need to cure before the building shows up?

Your supplier's engineered drawings set the minimum cure time the pad needs before the frame goes up and the anchors take load. Concrete keeps gaining strength for a while after that too, with 28 days the point most engineering specs are built around, but the pad doesn't have to wait that long: we schedule the pour early enough to clear your supplier's minimum with room to spare.

Cold or wet weather slows curing, so we build a few extra days into that schedule when the forecast calls for it.

Metal buildings, carports and the pad they need

We can recommend the buildings too, through the metal building company we partner with. Our metal buildings page shows what we can recommend, and our metal building kits, carport kits and barndominium kits guides cover how each one anchors and what the slab underneath has to carry.

Once you've got a building picked out or in mind, send us the building's drawings, or just the size and the address, and we'll size the pad and schedule the pour ahead of your delivery date.