Polk County, Iowa - Public Works, Building Services

Polk County, Iowa

county

5885 NE 14th St, Des Moines, IA 50313

Required

Required

Per Polk County's own Building Services webpage, permit applications are submitted through the county's online portal (OpenGov); a paper permit application is available on request by contacting staff. Contractors must register with the county through the portal before filing an application. Building Services can be reached at 515-286-3705 to schedule inspections, which are handled first-come, first-served, and the permit holder (or their representative) is responsible for calling in inspection requests.

Polk County has adopted the 2021 Edition of the International Residential Code for One- and Two-Family Dwellings (including Appendix F and Appendix M) by reference at Polk County Construction Code (county code Chapter 20) Sec. 20.2.4, "Polk County Residential Code," governing one- and two-family dwellings and townhouses up to three stories in unincorporated Polk County. The ordinance was enacted effective September 2, 2024. Section 20.2.4 lists 39 numbered amendment items to the 2021 IRC (running from Section R101.1 through Section R507.3, then jumping directly to Chapter 11 Energy Efficiency); read in full, none of the 39 items touches IRC Chapter 9 (Roof Assemblies).

Required — Polk County adopts the 2021 International Residential Code by reference at Construction Code Sec. 20.2.4. Its amendment list there (39 numbered items, read in full) does not touch IRC Chapter 9 (Roof Assemblies), so the base 2021 IRC drip-edge provision applies unmodified. About drip edge

Required — Polk County's own Table R301.2(1) insert at Construction Code Sec. 20.2.4, item 18 (applicable to the 2021 IRC as adopted for unincorporated Polk County), lists "Ice Shield Under Layment Required: Yes" as a filled-in table cell for the jurisdiction. The same table appears verbatim on the Building Services webpage. About ice & water barrier

Not required — Polk County adopts the 2021 International Residential Code by reference at Construction Code Sec. 20.2.4. Its amendment list there (39 numbered items, read in full) does not touch IRC Chapter 9 (Roof Assemblies); no UL 2218 or Class 4 impact-resistance requirement appears anywhere in the 48-page Construction Code, including its own Table R301.2(1) insert (which fills in snow, wind, seismic and ice-shield criteria but includes no windborne-debris or impact-rating column).

The Polk County Construction Code amends IRC Section R105.2 (Work Exempt from Permit) to route to the county's own exemption list at Sec. 20.1.11 of Chapter 20. That list, read in full (17 building-permit exemption items plus separate lists for electrical/gas/mechanical/plumbing work, general repairs, and grading), contains no exemption for re-roofing or reshingling at any size or dollar value. The county's 2026 Public Works Fee Schedule's general Building Permit Valuation Table begins at a "$1-$500" valuation tier with a base fee, i.e. no minimum-valuation floor below which a residential building permit is not required.

Table R301.2(1) (Climatic and Geographic Design Criteria) as filled in by Polk County at Construction Code Sec. 20.2.4, item 18, applicable to the 2021 IRC for unincorporated Polk County: Ground snow load 30 psf; ultimate design wind speed 115 mph; seismic design category A; weathering (concrete masonry) Severe; frost line depth 42 inches; termite damage No; winter design temp -5 F; ice shield underlayment required Yes; flood hazards NFIP effective date 2-1-2019; air freezing index 1833; mean annual temperature 48.6 F.

Polk County adopts the 2021 International Residential Code by reference at Construction Code Sec. 20.2.4. Its amendment list there (39 numbered items, read in full) does not touch IRC Chapter 9 (Roof Assemblies), so the base 2021 IRC provisions on roof recovering and layer limits apply unmodified.

Polk County adopts the 2021 International Residential Code by reference at Construction Code Sec. 20.2.4. Its amendment list there (39 numbered items, read in full) does not touch IRC Chapter 9 (Roof Assemblies), so the base 2021 IRC provisions on roof deck sheathing apply unmodified.

The Iowa Department of Revenue's own published Local Option Sales Tax (LOST) workbook, "LOST by County" tab (effective 7/1/2026), lists unincorporated Polk County with no local option sales tax, for a total rate of 6% (the state base rate only). Rates vary by city within Polk County: most incorporated cities in the county carry a 1% local option tax for a combined 7% total (e.g. Des Moines, Altoona, Bondurant, Clive, Grimes, Johnston, West Des Moines, Windsor Heights), while Ankeny, Norwalk, Saylorville and Waukee are listed with no local option tax and remain at 6%. A roofer should confirm the rate for the specific city or unincorporated township where the job site sits rather than assume a single county-wide rate.