Do I need a permit for roof replacement in
Des Moines, Washington?

Des Moines roof replacement permits—the key details

Des Moines Building Department uses the 2021 Washington State Building Code (which adopts the 2021 IBC and IRC with state amendments). The critical rule for roofing is IRC R907, which governs reroofing: if you are installing a new roof covering over existing shingles, the city requires a permit whenever the new material covers more than 25% of the roof area. Tear-off-and-replace always requires a permit. The code also states in IRC R907.4 that if the existing roof assembly has three or more layers of shingles, they must all be removed before new shingles are installed—the city's inspector will physically check this in the field during framing inspection. This is a hard line: if three layers are found and the permit assumed only two existed, the permit is stopped and you must hire a roof removal specialist to strip the deck bare, which adds $1,500–$3,000 to your project.

The Puget Sound climate (zone 4C west of I-5; zone 5B east) drives underlayment requirements that trip up many DIY permittees. IRC R905.1.1 requires ice-and-water shield in the Puget Sound region extending a minimum of 24 inches up from the eave on unheated buildings, or as specified in the manufacturer's instructions if more aggressive. Des Moines inspectors have flagged permits where homeowners specified standard synthetic underlayment without ice-and-water shield at eaves; the city then red-tags the permit and requires a plan revision before work continues. If you are changing roof material—say, from asphalt shingles to standing-seam metal or clay tile—you must submit a structural evaluation with your permit application, because metal and tile load the deck differently than shingles. The city will not approve a material-change reroofing permit without this documentation. Metal roofing adds about 1.5–2 pounds per square foot; tile adds 9–15 pounds per square foot. An older deck may need reinforcement.

Des Moines allows owner-occupant self-permitting for residential reroofing, but the city's permit process is largely paper-and-email, not 24/7 online. You contact the building department, submit a completed roof plan (showing slope, material, underlayment type, and fastening pattern) plus a copy of the roof-cover warranty, pay the permit fee (typically $150–$300 depending on roof square footage), and wait 3–5 business days for issuance. Most reroofing permits in Des Moines are issued over-the-counter because they are like-for-like replacements with no structural changes; however, if the permit reviewer sees missing details (like ice-and-water shield specs), they will request a revision before issuing. Once the permit is issued, you will have an in-progress inspection (the inspector walks the deck to confirm materials, underlayment, and fastening), and a final inspection (confirms code compliance and contractor workmanship). Unlike some cities, Des Moines does not require a structural engineer's stamp for standard shingle reroofing, but the inspector will visually assess deck condition during the in-progress inspection and flag rot or structural issues.

A unique local feature: Des Moines sits at the boundary of FEMA flood zones, and several neighborhoods are in the 100-year floodplain. If your address falls within a flood zone, your permit will reference flood-damage-resistant materials and installation. Roofing itself is not typically affected, but if your reroofing permit pulls a larger project (e.g., soffit replacement or deck repair), the flood designation will trigger additional underlayment and flashing requirements per the local flood code. Check your property's FEMA flood zone status before submitting; the city can tell you in one phone call. Additionally, Des Moines does not have a historic district overlay that affects reroofing (unlike some cities, which require period-correct materials in certain zones), so material choice is unrestricted as long as it meets code.

Contractors typically pull the permit on behalf of homeowners, and most will include the permit fee in their quote. If you are hiring a roofer, confirm in the contract that the roofer is pulling the permit, obtaining inspections, and the warranty is contingent on passing final inspection. Some unscrupulous roofers will skip permits to appear cheaper; this is a red flag—it usually means they will not show up for inspections, will not carry liability insurance, and your home will not be properly insured if something goes wrong. If you are self-permitting, you do the actual work (or you hire a roofer to do labor only under your owner-builder permit), and you are responsible for scheduling inspections and ensuring all code requirements are met before final sign-off. The city can take 1–2 weeks to get an inspector to your site, so plan accordingly.

Three Des Moines roof replacement scenarios

Why Des Moines inspectors flag three-layer roofs (and why this costs you)

In the 1960s–1980s, roofing contractors often installed new shingles over old shingles without removing the prior layer. By the early 2000s, building codes had tightened, and IRC R907.4 prohibited reroofing over a roof assembly with three or more existing layers. Des Moines Building Department strictly enforces this rule. If a permit is issued for a reroofing project and during the in-progress or final inspection the inspector discovers three layers (by physically probing the roof edge or removing a small section at the eave to count), the permit is red-tagged, work stops, and you must hire a licensed roof removal contractor to strip all existing layers to bare deck before you can proceed with new installation.

This costs an additional $2,000–$3,500 depending on roof size and deck condition (removal contractors charge $1–$2 per square foot plus disposal). It also delays the project by 1–2 weeks. To avoid this surprise, ask your roofer or climb into the attic and visually count layers at the eaves (you can often see them where the roof meets the fascia). If you suspect three or more layers, disclose this to the city in your permit application and budget for removal upfront. Des Moines inspectors respect transparency; if you tell them in advance, they will approve a scope that includes removal. If you try to hide it and they find it, they will fine you.

Why does the code require this? Multi-layer roofs trap moisture and heat in the assembly, leading to premature deterioration of underlayment and wood deck. They also mask deck damage, and the added weight can overload older roof framing if there is a fourth or fifth layer lurking beneath.

Ice-and-water shield in the Puget Sound climate: what Des Moines inspectors actually check for

Des Moines sits in the Pacific Northwest's maritime climate zone (4C west of I-5; 5B east). Winters are wet and mild, freeze-thaw cycles are common, and ice dams form when warm attic air melts snow, which then refreezes at the eave. IRC R905.1.1 mandates ice-and-water shield in these climates, extending from the eave upslope a minimum of 24 inches (or per manufacturer's specs if more aggressive). Des Moines Building Department specifically calls this out in their permit guidelines: the ice-and-water shield must be synthetic or rubberized asphalt, not just standard felt underlayment.

During the in-progress inspection, the city inspector will walk the roof and visually confirm that ice-and-water shield is in place at the eaves before the main shingles are installed. If you submit a permit plan that says synthetic underlayment without specifying ice-and-water shield, the permit reviewer will email you requesting a clarification before issuing. This is a low-cost fix on paper, but if your roofer has already started work and did not install ice-and-water shield, the inspection will fail and you will have to remove shingles, install the shield, and reinstall shingles—a $500–$1,000 do-over.

The best practice: include a line on your permit plan that explicitly states 'Ice-and-water shield, synthetic, minimum 24 inches from eave per IRC R905.1.1.' Include a photo of the product you are using (show the label). Des Moines will approve it immediately. It costs an extra $50–$100 in materials and ensures you pass inspection on the first try.

Common questions