DADU Specialist & General Contractor in Seattle
From custom DADU construction and full home remodels to roofing, siding, and decking — Cost Construction delivers craftsmanship that lasts. Licensed, bonded, and proudly serving the Greater Seattle area.
Years in Business
Projects Completed
Client Satisfaction
DADU Units Built
General Contractor Services in Seattle
Detached Accessory Dwelling Units
Seattle's leading DADU specialist. We handle every phase — from permit navigation and design to foundation, framing, and final finishes. Add rental income or multigenerational living to your property.
Kitchen, Bath & Full Renovations
Transform your existing space with a full home remodel. From kitchen and bathroom renovations to open-concept conversions and basement finishing, we bring your vision to life on time and on budget.
Installation, Repair & Replacement
Protect your home with a roof built for the Pacific Northwest's demanding weather. We install architectural shingles, metal roofing, and flat roof systems with industry-leading warranties.
Installation & Replacement
Boost curb appeal and energy efficiency with new siding. We specialize in fiber cement, vinyl, and cedar siding — all installed with precision and backed by manufacturer warranties.
Custom Deck Design & Build
Extend your living space outdoors with a custom-built deck. We design and build composite, cedar, and Trex decks that stand up to Seattle's wet climate while looking beautiful year-round.
24/7 Residential & Commercial
Locked out? Need a lock upgrade after a break-in? Our licensed locksmiths provide fast emergency response across Seattle — residential, commercial, and automotive locksmith services available 24/7.
Recent Projects
650 sq ft modern DADU with cedar siding and rooftop deck
Open-concept kitchen with custom navy cabinetry and quartz counters
Full architectural shingle replacement on 2,400 sq ft home
James Hardie fiber cement siding with custom trim package
Multi-level Trex composite deck with pergola and built-in seating
5.0 average across 80+ reviews
"We hired Cost Construction for a full kitchen remodel and couldn't be happier. The project lead kept us informed every step of the way, the crew was professional and respectful of our home, and the finished kitchen looks stunning. On time and on budget — rare in Seattle!"
"Cost Construction transformed our home with a beautiful DADU. Professional, on-time, and within budget. Highly recommended!"
"Best roofing contractor we've worked with. Professional, clean, and the work is impeccable. Worth every penny!"
"Called for emergency locksmith service at 2 AM. They arrived in 20 minutes and solved the problem. Fantastic service!"
"Our deck is beautiful and built to last. The team was professional, courteous, and left our yard spotless. Thank you!"
Mon–Sat: 7am – 6pm