Quick Answer
Dirt floor ($1-3/sq ft) - Simplest, agricultural use only
Gravel ($2-4/sq ft) - Better drainage, still agricultural
Concrete slab ($5-10/sq ft) - Standard for most buildings
Concrete piers ($6-12/sq ft) - Posts mounted above ground
Perma-Column ($15-25/sq ft) - Concrete column with bracket
Choose based on building use, budget, and site conditions.
Foundation Options
Dirt Floor
Simplest option. Compacted native soil.
Best for: Loafing sheds, temporary storage, budget builds
Gravel
Compacted gravel, 4-6" deep.
Best for: Equipment storage, agricultural, better drainage than dirt
Concrete Slab
4-6" concrete, reinforced.
Best for: Most applications, workshops, garages, finished spaces
Concrete Piers
Posts mount on piers above slab grade.
Best for: Poor soil, high water table, easy post replacement
Perma-Column
Pre-cast concrete column with bracket.
Best for: Professional installation, longevity, easy replacement
Common Questions
Q: Can I add a slab later?
A: Yes, but challenging. Posts must be cut off or slab poured around them. Plan ahead if slab is desired.
Q>What's most popular?
A: Concrete slab with embedded posts. Standard pole barn method.
Sources
- Perma-Column, "Foundation Options"
- Simpson Strong-Tie, "Post Foundations"