Cosine Contracting LLC

General · Woodinville, WA · License #COSINCL756B3

Subser ConfidenceListedActive WA license

Cosine Contracting LLC is one of 727 General contractors registered in Woodinville, registered with WA L&I since 2025. Current filings: $30,000 surety bond (continuous) and $1,000,000 liability coverage through Jan 20, 2027. Principals on record since 2025.

How confident can you be in Cosine Contracting LLC?

Are they licensed, bonded, and insured?

Active license, $30,000 bond and $1,000,000 liability on file — checked against WA L&I records, updated daily.

Source:License facts on this pageVerify at WA L&I

Are they who they say they are?

Not yet verified — Cosine Contracting LLC hasn't claimed this listing. Own this business? Claim it free.

Do other pros stand behind them?

No endorsements yet from other licensed contractors in Woodinville.

Do they have jobs on record?

Not yet measured — Cosine Contracting LLC hasn't run jobs through Subser. Performance data comes from real jobs, not reviews.

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License facts

License type
CONSTRUCTION CONTRACTOR
Effective date
Jan 23, 2025
Expiration date
Jan 23, 2027
UBI
605649333
Business type
Limited Liability Company
Phone
(425) 659-4345
Location
Woodinville, WA 98072

Source: WA L&I contractor registration — checked Aug 18, 2026. Applies to every row above.

Registration is current through Jan 2027.

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Bond & insurance on file

Bond firmAmountEffectiveExpiration
Western Surety Co$30,000Jan 21, 2025Continuous — until canceled
Insurance companyAmountAgencyEffectiveExpiration
Clear Blue Specialty INS$1,000,000Insurance Resources & ServicesJan 20, 2025Jan 20, 2027
What the bond and insurance requirements mean for homeowners

Registration as a general contractor in Washington requires a $30,000 surety bond on file with the Department of Labor & Industries. This contractor's current filing shows a $30,000 bond.

The bond is a limited fund a homeowner (or subcontractor or supplier) can make a claim against, through the courts, if a registered contractor fails to meet its obligations on a job. Contractors must also keep general liability insurance on file — at least $50,000 in property damage and $200,000 in public liability coverage, or a $250,000 combined single limit — which covers damage the contractor causes, not workmanship disputes. The rows above are the bond and insurance filings L&I publishes for this registration; whether a specific filing applies to a specific project depends on its dates and terms.

Principals

NameStart date
John TrenkampJan 23, 2025
What is a General contractor licensed to do in Washington?

A general contractor in Washington is registered with the Department of Labor & Industries to perform or oversee work in multiple building trades. General contractors can take on whole projects — remodels, additions, new construction — and can hire specialty subcontractors for individual trades. A $30,000 surety bond and general liability insurance, filed with WA L&I, are required for this registration. Washington currently lists 727 General contractors registered in Woodinville.

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Subser doesn't have reviews or star ratings. This page shows Cosine Contracting LLC's WA L&I record — registration status, bond and liability coverage, and principals on file — plus any endorsements from other licensed contractors.

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Built from Washington State L&I public records, updated Aug 18, 2026. Subser doesn't do star ratings or reviews — just verified records.