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Questions to Ask Before Hiring a Deck or Patio Contractor

You're ready to add a deck or patio to your Seattle-area home. Maybe you're picturing summer evenings with a view of the Olympics, or finally having a usable outdoor space that isn't a muddy slope. But before you sign a contract, you need to make sure you're hiring someone who will build it right, keep it legal, and stand behind their work.

Western Washington's wet winters, occasional freezing snaps, and summer sun put real demands on outdoor structures. A deck or patio built without proper drainage, flashing, or materials suited to our climate won't last. On top of that, Seattle and King County have specific permit requirements and building codes that your contractor needs to navigate correctly—or you could end up with fines, required teardowns, or trouble selling your home down the line.

This checklist walks you through the essential questions to ask any deck or patio contractor before you hire. Use it to compare quotes, spot red flags, and move forward with confidence.

Licensing, Bonding, and Insurance in Washington State

Washington requires contractors to be licensed, bonded, and insured. This isn't optional, and it protects you if something goes wrong. Here's what to verify:

Contractor registration number: Every contractor working on projects over $1,000 must be registered with the Washington State Department of Labor & Industries (L&I). Ask for their registration number and verify it online at L&I's contractor search portal. Make sure the license is current and that there are no unresolved complaints or violations.

General liability insurance: This covers property damage and injuries that happen during the project. Ask for a certificate of insurance and confirm it's active. If a worker is injured on your property or your neighbor's fence gets damaged, you want the contractor's insurance handling it—not yours.

Bonding: Washington contractors must carry a surety bond. If the contractor fails to complete the work, violates the contract, or doesn't pay subcontractors or suppliers, you can file a claim against that bond.

Workers' compensation coverage: If the contractor has employees, they must carry workers' comp insurance in Washington. If they don't and a worker is injured, you could be held liable. Ask for proof or verify their coverage through L&I.

Questions to Ask:

  • "Can I see your current Washington contractor registration number and verify it online?"
  • "Do you carry general liability insurance and workers' comp? Can you provide certificates?"
  • "Are your subcontractors also licensed and insured?"

Permits and Inspections

Most decks and many patios require permits in Seattle and King County. The rules depend on the size, height, and location of your structure. Elevated decks almost always need permits. Ground-level patios may not, depending on materials and drainage, but it's always safer to check.

A good contractor knows what permits are required for your specific project and handles the application process. They should also schedule inspections at the right stages—typically a footing inspection before pouring concrete, a framing inspection before decking goes on, and a final inspection.

Skipping permits is a serious mistake. If you try to sell your home later, unpermitted work can kill a deal or force you to tear out the structure and rebuild it to code. Seattle's Department of Construction and Inspections (SDCI) keeps records, and buyers' inspectors will find unpermitted additions.

Questions to Ask:

  • "Will this project require permits? Which ones?"
  • "Do you handle the permit applications and scheduling inspections, or is that on me?"
  • "What happens if the project doesn't pass inspection?"

Project Timeline and Schedule

Seattle weather is unpredictable, especially outside the summer months. Rain delays are normal from October through May, and contractors need to plan around that. A realistic contractor will give you a timeline with some buffer and explain how weather might affect it.

Be wary of contractors who promise an unrealistically fast turnaround, especially during busy season. Quality deck and patio work takes time—site prep, footings or base layers, framing, decking or pavers, railings, and finishing details all need to be done properly.

Questions to Ask:

  • "What's the estimated start date and completion timeline?"
  • "How do you handle weather delays?"
  • "Will you be working on other jobs at the same time, or is this your focus?"
  • "What's your communication process if the schedule changes?"

Materials and Design for Western Washington's Climate

Not all decking materials perform equally well in our wet, mild climate. Pressure-treated lumber is affordable and common, but it needs regular maintenance. Cedar is naturally rot-resistant and popular in the Northwest, but still requires occasional sealing. Composite decking costs more upfront but handles moisture well and requires less maintenance.

For patios, drainage is critical. Seattle's clay-heavy soils don't drain quickly, so proper base prep and grading are essential. Pavers, stamped concrete, and natural stone all work, but the contractor needs to account for freeze-thaw cycles (we get a few each winter) and ensure water drains away from your foundation.

Questions to Ask:

  • "What materials do you recommend for this project and why?"
  • "How do these materials perform in Seattle's wet climate?"
  • "What kind of maintenance will be required?"
  • "How will you handle drainage and grading?"

Warranty and Post-Project Support

A solid contractor stands behind their work. Ask what kind of warranty they offer on labor and materials. Material warranties often come from the manufacturer (composite decking brands, for example, offer long warranties), but labor warranties come from the contractor.

Understand what's covered and for how long. A one-year labor warranty is common, but some contractors offer more. Also ask how they handle callbacks if something isn't right after the project wraps.

Questions to Ask:

  • "What warranty do you offer on labor? On materials?"
  • "If something goes wrong in the first year, how quickly will you come back to fix it?"
  • "Can I see examples of how you've handled warranty issues in the past?"

References and Past Work

Any contractor worth hiring should be happy to share references from recent projects—ideally in your area, ideally similar in scope to yours. Ask to see photos of completed decks or patios, and if possible, visit a job site or a past client's home.

When you call references, ask about communication, cleanliness, timeline, and whether they'd hire the contractor again. Also ask if there were any surprises or issues and how the contractor handled them.

Questions to Ask:

  • "Can you provide three references from projects in the last year?"
  • "Do you have photos of recent deck or patio projects?"
  • "Can I see a current or recent job site?"

Contract and Payment Terms

Everything you discuss should end up in a written contract. That contract should spell out the scope of work, materials, timeline, payment schedule, permit responsibilities, and warranty terms. Never work off a handshake or a vague estimate.

Washington law limits how much a contractor can ask for as a deposit. For projects over $1,000, they can't require more than one-third of the contract price or $1,000, whichever is less, before work begins. Be cautious of anyone asking for large upfront payments.

Payment schedules typically break the job into phases—deposit, progress payments tied to milestones (footings poured, framing complete, etc.), and a final payment after inspection and cleanup.

Questions to Ask:

  • "Will I receive a detailed written contract before work begins?"
  • "What's the payment schedule?"
  • "What happens if I want to make a change mid-project?"
  • "Who's responsible for cleanup and disposal?"

Red Flags to Watch For

Trust your gut. If something feels off, it probably is. Here are a few warning signs:

  • No license, or a license that's expired or belongs to someone else
  • Pressure to pay in cash or skip permits
  • Vague answers about insurance or warranties
  • No references, or references that seem scripted
  • A bid that's dramatically lower than others without a clear reason
  • Poor communication or unprofessional behavior during the estimate

FAQ

Do I need a permit for a ground-level deck in Seattle?

It depends on the size and height. In Seattle, decks that are less than 30 inches above grade and under 200 square feet may not require a permit, but rules vary by jurisdiction and site conditions. Always check with Seattle's Department of Construction and Inspections or your local building department, and expect your contractor to know the answer for your specific project.

How long does a typical deck project take in the Seattle area?

Most residential decks take one to three weeks to complete, depending on size, complexity, and weather. Larger or custom decks with built-in features like benches, planters, or multi-level designs will take longer. Permit approval can add another week or two before construction begins. Expect delays if you're building during the rainy season.

What's the difference between a deck and a patio when it comes to permits?

Decks are elevated structures attached to your house or freestanding, and they almost always require permits and inspections because of structural and safety concerns. Patios are ground-level surfaces, often made of concrete, pavers, or stone. Simple patios may not require permits, but if they involve significant grading, drainage work, or are close to property lines, permits might still be necessary. Your contractor should clarify this during the estimate.

Hiring the right deck or patio contractor in Seattle comes down to doing your homework. Ask these questions, verify credentials, read the contract carefully, and don't rush the decision. A well-built outdoor space will give you years of enjoyment and add real value to your home—but only if it's done right from the start.