ADU Builder Index

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Collaborative Construction LLC

1completed ADU permits
2total ADU permits
2016–2016active years on record
$541,687median est. project cost

Washington state license

License
COLLACL929QQ
Status
license re-licensed
Type
CONSTRUCTION CONTRACTOR
Expires
2023-01-19
Registered in
SEATTLE, WA

As reported by WA L&I on 2026-08-30. Always re-verify at lni.wa.gov/verify.

Permit record

Every ADU-related permit in covered city records naming this contractor. Links go to each city's official permit portal.

PermitCityIssuedStatusEst. costAddressDescription
6498358-CN2016-10-05Issued$541,687607 18TH AVE SEstablish use as single family residence and construct one family dwelling with accessory dwelling unit per plans.
6498358-EXCompleted607 18TH AVE SException/Exemption Request for: Establish use as single family residence and construct one family dwelling with accessory dwelling unit per plans.

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