An action may be brought 2 years after claim for relief arises. COLO. REV. STAT. § 13-80-102. In no event can the action be brought more than 6 years after substantial completion of improvement. If the cause of action arises during 5th or 6th year after substantial completion of the original construction date, it shall be brought  within 2 years after the date the cause of action arises. COLO. REV. STAT. § 13-80-104.