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Cosine Contracting LLC

Cosine Contracting LLC is a construction business established in 2025 and based in Woodinville, Washington. John Trenkamp is the owner/operator. Cosine Contracting is registered with Labor and Industries as a General Contractor and is bonded and insured. Cosine Contracting is committed to providing craftsmanship and exceptional value for homeowners and small business. I'd welcome the opportunity to collaborate on your next home improvement project. Contact me to schedule a free bid proposal.

- Typical Projects
- decks, fences, trellis, sheds, tree houses and covered roofs
- windows, siding, doors and trim
- floors, trim, drywall, texture and painting
- bathroom and kitchen remodels
- catios
- handyman
Contact:
John Trenkamp
Cosine Contracting LLC
PO BOX 2945
Woodinville, WA 98072
UBI #: 605-649-333
cosinecontracting@gmail.com
425-659-4345

Portfolio Pictures

cedar_deck Western Red Cedar Deck

alaska_deck Alaskan Yellow Cedar Deck

shower Shower Remodel

stairs Matching Stairs for a Deck

greenhouse Green House

bedroom Bedroom Makeover

shed Shed

treehouse treehouse Tree House in progress and complete

wood_shed Wood Shed

treehouse treehouse Wall repair before and complete