Wash. Rev. Code § 72.01.110
The department may employ the services of competent architects for the preparation of plans and specifications for new buildings, or for repairs, changes, or additions to buildings already constructed, employ competent persons to superintend the construction of new buildings or repairs, changes, or additions to buildings already constructed and call for bids and award contracts for the erection of new buildings, or for repairs, changes, or additions to buildings already constructed: PROVIDED, That the department may proceed with the erecting of any new building, or repairs, changes, or additions to any buildings already constructed, employing thereon the labor of the inmates of the institution, when in its judgment the improvements can be made in as satisfactory a manner and at a less cost to the state by so doing.
RCW 72.01.110
Public works: Chapter 39.04 RCW.