Home Addition Drawings · Des Moines, WA
Permit-Ready Home Addition
Drawings for Des Moines, WA
Expand your home with a permitted room addition, second story, or family room extension. We deliver complete, code-compliant drawing sets for Des Moines's building department — 14-day money-back guarantee.
14-day money-back guarantee · permit-ready delivery
Local Intelligence
What Des Moines Homeowners Need to Know Before Submitting
Size & Zoning Rules
Any new square footage added to your Des Moines home counts against the same zoning envelope that governs ADU size, meaning large additions may affect your ability to add a future ADU. Des Moines's current ADU size cap is 1,200 sq ft — generous enough to accommodate most project types.
Des Moines does not impose an owner-occupancy requirement, so you can rent both the main home and any ADU or conversion as investment units.
If the addition creates a second unit or is later converted to a rental, Des Moines's ADU market supports approximately $1,995/month for a 2-bedroom unit.
Permit Process & Fees
Building Division permit fees for this project type typically range from $9,000 to $28,000 depending on project valuation and scope. Plan check runs approximately 10 weeks — though each correction cycle adds 3–6 weeks, which is why code-compliant drawings matter so much.
Addition permit packages submitted to Building Division must include a site plan, floor plans, all four elevations, an electrical plan, and energy compliance documentation — plus stamped structural drawings are always required for any load-bearing elements, second-story work, or new foundation.
Visit Building Division ↗Construction Cost Context
Des Moines's home addition construction costs run $244–$510 per square foot — a wide range driven by labor markets, local code complexity, and finish level. Our drawings are priced at a fraction of what a full-service architect would charge to produce the same permit set.
⚠ Common Pitfall in Des Moines
Homes near the bluffs or shoreline in Des Moines often fall inside the state's coastal overlay zone, which means you'll need a separate Shoreline Substantial Development Permit on top of your regular building permit — this can tack on 6-8 extra weeks and requires a habitat/environmental review before the Building Division will even look at your plans. Because the city sits in Seismic Zone D, engineers also tend to require deeper footings or additional shear wall bracing than you'd see in a typical Puget Sound suburb, which can push your structural plan check costs up unexpectedly. On top of that, older neighborhoods like Woodmont and Redondo frequently have undersized side sewer lines from the 1960s, so King County may require a sewer capacity check before signing off on your final utility connection.
Expert Verdict — Marcus Reid, Licensed Designer
"In my experience, that 10-week timeline and per-sqft cost figure are Des Moines state-level estimates rather than locally verified numbers, so I'd call the Building Division directly and get a couple of local contractor quotes before penciling in a budget or start date — and don't overlook that coastal overlay, because the CDP review adds real time on top of standard plan check that a lot of homeowners don't anticipate."
Market Context
Des Moines has a median home value of $560,000. Comparable renovation projects in this market typically add 25% to resale value.
Neighborhoods in Des Moines with the strongest home addition and resale value potential include Highline College Area, Marina District, Central Des Moines, Pacific Ridge, North Hill. Extreme rental demand driven by the large student population of Highline College.
Permit Process
Permit applications are reviewed by the Building Division, with a plan check timeline of approximately 10 weeks. Permit fees in Des Moines range from $9,000 to $28,000 depending on project scope. Design review: Yes - critical area review (and historic district review if applicable).
Des Moines falls within Seismic Design Category D, which affects structural requirements for any new addition tying into the existing structure.
Properties within Des Moines's Coastal Overlay Zone require a Coastal Development Permit in addition to standard building permits.
Local Financing Resources
Local Home Addition Lenders in Des Moines
These lenders offer HELOC, construction, and renovation loans for home addition projects in King County. Compare terms before committing.
Washington's largest credit union; nearest branch 25250 Pacific Hwy S (Redondo/Kent, ~2 mi from Des Moines 98198); HELOC intro rate as low as 4.49% APR for 6 months, also offers construction and home-improvement loans.
Visit Lender ↗Serves South King County with nearby branches in Federal Way, Kent, Burien, and Tukwila; offers two-time-close construction loans usable for major renovations and ADUs; HELOC intro of 4.99% APR for 6 months also available.
Visit Lender ↗Has a branch inside Des Moines WA at 21401 International Blvd (98198); offers construction-to-permanent loans and HELOCs (Washington HELOC APR around 6.375%), suitable for ADU projects.
Visit Lender ↗Washington-state savings bank with a dedicated ADU financing program offering six loan options designed for ADU builds ($150k–$250k typical cost); also offers HELOC (6.875% variable APR, up to $400k) and construction loans.
Visit Lender ↗Specialty ADU/renovation fintech that partners with credit unions nationwide (including Washington) to offer ARV-based renovation loans — borrowers get up to 11x more borrowing power on average vs. standard HELOCs without refinancing the first mortgage.
Visit Lender ↗Build With A Plan is not affiliated with these lenders. Always compare rates and consult a mortgage professional.
Local Build Partners
Vetted Home Addition Contractors in Des Moines
We draw the plans. These contractors build the addition. Independent — no referral fees paid or received.
Build With A Plan provides drawings only. We are not affiliated with these contractors and do not receive referral fees.
Free — No Obligation
What Will Des Moines Let You Add?
Setbacks, lot coverage, and height limits decide your addition before a single line is drawn. Send us the address and we’ll tell you what’s actually approvable — free, before you commit to a design.
- ✓Maximum footprint your lot and setbacks allow
- ✓Lot-coverage and height limits in Des Moines
- ✓Whether your addition triggers structural or energy upgrades
- ✓Realistic plan-check timeline for your project
- ✓A straight answer within 48 hours
Review My Project — Free
Takes 60 seconds. We'll deliver your personalized report within 48 hours.
Request Received
Your feasibility report is being prepared. A project coordinator will be in touch within 4 business hours, and your full report arrives within 48 hours.
Drawing Package Details
What's Included in Your Des Moines Home Addition Package
What You Get
What's in Your Des Moines Home Addition Package
One-time fee, no retainer, no hourly billing — your exact scope and price confirmed on a free call.
- ✓Site plan
- ✓Floor plans (existing + proposed)
- ✓All 4 elevations
- ✓Electrical plan
- ✓Title 24 energy compliance
- ✓PDF + DWG delivery
- ✓10 business day turnaround
- ✓Everything in Starter
- ✓Stamped structural drawings
- ✓Foundation plan
- ✓Roof framing plan
- ✓Window & door schedules
- ✓1 round of revisions
- ✓Everything in Standard
- ✓3D rendering
- ✓Cross-section details
- ✓Material specifications
- ✓HOA submission package
- ✓2 rounds of revisions
- ✓Priority 5-day turnaround
After You Order
Your Addition Drawings in 3 Steps
Submit Your Project Details
Share your property address, existing floor plan (if available), and the addition scope. We assign your project coordinator within 4 business hours.
We Draft Your Drawings
Our team designs your complete addition drawing set — engineered for Des Moines's building department requirements and WA CBC code. Delivered in 10 business days.
Submit to Your Building Dept
Download your complete package and submit to Building Division. We support plan check corrections at no extra charge.
Common Questions
Des Moines Home Addition FAQs
Do I need a permit for a home addition in Des Moines? +
Yes — any structural addition to your home in Des Moines requires a building permit. This applies to room additions, second-story additions, sunrooms, and attached garages. You'll need permit-ready drawings before the building department will accept your application. Our packages are formatted specifically for Des Moines's submittal requirements.
How much does a home addition cost in Des Moines? +
Home additions in Des Moines typically cost between $150–$400 per square foot depending on the scope, finishes, and structural complexity. A 600 sq ft addition ranges from $90,000 to $240,000. Second-story additions cost more than ground-floor extensions due to structural requirements. Contact us to discuss drawing package options for your project.
What drawings are required to permit a home addition in Des Moines? +
Des Moines's building department requires: a site plan showing the addition's footprint and setbacks, floor plans for all affected levels, all four exterior elevations, an electrical plan, and energy compliance (Title 24 in California). Structural plans stamped by a licensed engineer are required for any load-bearing elements — included in our Premium package.
How long does the permit process take for a home addition in Des Moines? +
Plan check in Des Moines typically takes 10 weeks for home additions. Additions with structural components may require additional review. Complete, code-compliant drawings significantly reduce correction cycles — each cycle adds 3–6 weeks. Our drawings are engineered to pass on the first submittal.
What setbacks apply to home additions in Des Moines? +
Des Moines enforces minimum setbacks from property lines for all additions: typically 4–5 ft side setbacks and 5 ft rear setbacks, though these vary by zoning district and lot size. Your addition must stay within the buildable envelope. Our site plan documents existing and proposed setbacks and flags any zoning variances required.
Do I need structural drawings for a home addition in Des Moines? +
Yes, for most additions. Any load-bearing walls, new foundations, second-story construction, or roof structure changes require stamped structural drawings from a licensed engineer. California's CBC (California Building Code) and seismic requirements make structural plans mandatory for most addition types. Our Standard and Premium packages include stamped structural drawings.
How much do home addition drawings cost in Des Moines? +
Our permit-ready home addition drawing packages for Des Moines include everything your building department requires — floor plans, elevations, structural, and energy compliance. Every package is engineered for WA code compliance and formatted for Des Moines's building department. 14-day money-back guarantee.
Will a home addition increase my home's value in Des Moines? +
In Des Moines, where median home values are approximately $560,000, a permitted home addition adds square footage that appraisers value as part of the home's gross living area. Return on investment varies by addition type — master suite additions, family room expansions, and additional bedrooms typically recoup 50–75% of project cost in appraised value in WA markets.
Can I add a second story to my home in Des Moines? +
Second-story additions are permitted in most Des Moines residential zones, subject to height limits and design review requirements. California generally requires ministerial permit approval, but some cities impose design compatibility or neighborhood compatibility review for second stories. Our drawings cover all levels including foundation upgrades, shear walls, and roof framing required for vertical additions.
Also Available in Des Moines
Adding an ADU instead? See our ADU design service.
Next Steps
Ready to Move Forward With Your Des Moines ADU?
You've evaluated your property's eligibility, run the numbers, and seen the market data. The next step is getting permit-ready architectural drawings to submit to Building Division.
Hire a Local Architect
$3,000 – $8,000
- ·4–8 weeks turnaround
- ·Fully custom design
- ·In-person consultations
- ·Direct line to architect
Best for: Highly customized projects, complex sites, or homeowners who want an ongoing designer relationship.
Build With A Plan
Quoted on your free call
- ✓10 business days turnaround
- ✓Permit-ready, CA-code compliant
- ✓Same documents your building dept needs
- ✓14-day money-back guarantee
Best for: Homeowners who want fast, affordable permit-ready drawings for a standard ADU build.
Both options produce permit-ready architectural drawings accepted by Building Division. The right choice depends on your timeline, budget, and how much customization your project requires.