Subgrade & Drainage
Strip organics, proof-roll, and compact per geotech. Provide positive drainage away from the slab (~5% fall for the first 10′).
- Well-graded base (4–6″ compacted).
- Plan swales and downspouts before pour.
Concrete Foundations for Metal Buildings
From subgrade and vapor barriers to rebar, joints, and drainage—then the specifics for Rigid Frame (red iron) vs Cold-Formed (C/Z): footings, grade beams, and anchor bolts that fit your stamped drawings.
1) Slab-on-Grade Fundamentals
Vapor Barrier & Reinforcement
Install a continuous vapor barrier with lapped seams. Typical slabs 4–6″ (verify with engineer).
Tip: coordinate slab thickness with door thresholds.
2) Rigid Frame (Red Iron) Foundations
Typical System
Isolated spread footings at main frames, tied by grade beams or slab per design.
- ComponentMain Frame Footings
Set to elevation; verify bearing and rebar per plan.
- ComponentAnchor Rods
Rigid templates; correct projection/embed; protect threads.
- ComponentGrade Beams
Tie footings laterally or support edges when specified.
- ComponentSlab
Sequence with erection; confirm F-numbers where required.
Anchors & Tolerances
Follow the manufacturer’s anchor-bolt plan exactly. Verify location and plumb prior to pour.
- Photo-log inspections.
- Double-nut leveling if specified.
- No field-slotting without engineer direction.
3) Cold-Formed (C/Z) Foundations
Typical System
Continuous perimeter grade beam with thickened edges or piers as needed.
- ComponentPerimeter Grade Beam
Reinforced; below frost; width/depth per engineering.
- ComponentAnchors / Straps
At column lines; keep straight and within projection.
- ComponentSlab-on-Grade
4–6″ typical; vapor barrier; isolation joint if required.
Frost, Elevation & Trim
Extend beam below frost; keep top above exterior grade; coordinate base trim and wall laps with anchors.
4) Checklists You Can Use
Before You Pour
- Soil report or bearing confirmation.
- Loads verified via CodeSmart™.
- Stamped drawings match building drawings.
- Anchor-bolt plan reviewed with concrete sub + erector.
- Joint layout and elevations confirmed.
During Placement
- Inspector sign-offs recorded.
- Anchors braced and threads protected.
- Vapor barrier intact; seams taped.
- Saw-cut timing per spec; edges clean.
After Cure
- Verify anchor locations; record as-builts.
- Repair spalls before steel arrives.
- Confirm slab flatness (F-numbers).
Common Mistakes
- Pouring before final anchor plan.
- Punctured or muddy vapor barrier.
- No isolation joints at grade beams.
- Slab elevation too low → splash-back at panels.
5) Important
Educational guidance only. Foundations must be designed and stamped by a licensed engineer for your site conditions and loads. Always confirm requirements with your local building department.