Cost Plus or Open Book Construction

A cost plus arrangement is very similar to the traditional fixed price method with the exception that the fee and reimbursable expenses are negotiated between Timcon Construction and the owner.

Once the drawings are completed the project is tendered to the trade contractors and suppliers. The worked is commenced. The contractor provides an "open book" for all project costs and is more accountable to the owner in terms of method of construction , cost substantiation and control of the work and trades. In return the owner takes full risk regarding the final cost of the project. Cost plus or open book arrangements are most often used where the full scope of the work is unclear due to possible concealed conditions such as renovation projects, difficult site or subsurface conditions and other types of unknown or undefined scope of work.


  • Owner only pays for work required
  • Savings accrue to owner
  • Allows earlier start and shorter overall project duration


  • Owner bears risk of overall project costs