A foundation is the most important pour on any building. In Iowa’s freeze-thaw climate, an out-of-spec footing or improperly waterproofed wall will cause structural issues within 5–10 years. DSM Concrete Pros pours residential and commercial foundations to Iowa Residential Code (IRC) and Polk County engineering specs.
Foundation Types We Pour
- Footings — minimum 16” wide x 8” deep, 42”+ below grade
- Basement walls — 8” or 10” poured concrete, full waterproofing
- Frost walls — for unheated additions, garages, outbuildings
- Slab-on-grade — monolithic slab with thickened edge footings
- Crawlspace foundations — block stem walls on poured footings
- ICF foundations — insulated concrete form walls for high-R-value builds
Iowa Frost Depth & Engineering
Des Moines frost line is officially 42 inches. We pour all exterior footings at 44–48 inches and tie them with #4 rebar grid (12” on center each way). Walls get vertical #4 rebar at 32” on center plus two horizontal continuous bars at top and bottom.
Waterproofing & Drainage
Every basement wall we pour gets:
- Rubberized asphalt or polymer membrane on exterior face
- Drainage board to redirect hydrostatic pressure
- 4” perforated drain tile in washed rock at footing base
- Tied to sump pit or daylight drain
Iowa soil holds water. Foundations without proper waterproofing leak inside 3 winters.
Pricing
| Foundation type | Range (per sq ft of footprint) |
|---|---|
| Slab-on-grade w/ thickened edge | $6 – $9 |
| Crawlspace footings + stem wall | $8 – $11 |
| Full basement (8’ walls) | $11 – $14 |
| ICF basement walls | $14 – $19 |
A typical 1,500 sq ft basement foundation runs $18,000–$22,000.
Process & Timeline
- Engineered plans review — we coordinate with your architect or GC
- Excavation — 1–3 days depending on size and access
- Footings — forms, rebar, pour, 3-day cure
- Walls — forms set, rebar tied, pour, cure 3–5 days
- Waterproofing + drain tile — before backfill
- Backfill — coordinated with framer/inspections
Iowa Code & Polk County Engineering
Foundations in the Des Moines metro are governed by the Iowa Residential Code (IRC, based on the 2018 IRC with state amendments). Critical local items:
- Footings below 42” frost line (we pour at 44–48” for margin)
- Engineered footings required where soil bearing capacity is below 1,500 PSF — common in floodplain areas near the Raccoon and Des Moines rivers
- Frost protection for shallow foundations (FPSF) permitted with engineered insulation detail
- Damp-proofing minimum on basement walls below grade; waterproofing required where the water table rises seasonally (most of Beaverdale, Sherman Hill, and older Drake)
- Radon mitigation rough-in required by IRC Appendix F where adopted — increasingly common in metro municipalities
Polk County also requires soil testing for any commercial foundation pour over 30 cubic yards. We coordinate with local geotech firms when a project requires it.
Foundation Failure Modes We Repair
The other half of foundation work is repair. Common failures in the Des Moines metro:
- Horizontal wall cracks — soil pressure on under-reinforced walls. Carbon-fiber strap repair if minor, wall replacement if severe
- Vertical cracks — usually shrinkage; sealed with structural epoxy injection
- Stair-step cracks in block — settlement; underpinning or polyurethane lifting
- Bowed walls — hydrostatic pressure plus inadequate rebar; wall bracing or rebuild
- Sulfate attack on older foundations — sub-2000 builds in agricultural soils sometimes show degradation; assessment determines repair vs replace
We inspect free of charge across the metro and provide a written assessment within 48 hours.
Common Foundation Project Sizes
| Project | Typical scope | Range |
|---|---|---|
| Garage addition footing + stem | 24’ × 24’ perimeter | $7,500 – $12,000 |
| Walkout basement (1,200 sq ft) | Full pour + waterproofing | $18,000 – $26,000 |
| Slab-on-grade for outbuilding | 30’ × 40’ (1,200 sq ft) | $9,000 – $13,500 |
| Commercial footings + slab (5,000 sq ft) | Engineered scope | $55,000 – $95,000 |
Service Area
Foundations poured across Des Moines, West Des Moines, Ankeny, Urbandale, Waukee, Clive, Altoona, Johnston, Grimes, Pleasant Hill, Norwalk, and surrounding Polk and Dallas County communities.