The Whole Building Design Guide (a program of the National Institute of Building Sciences) has published an informative guide to constructability reviews: Performing Efficient and Effective Constructability Reviews by Jason G. Smith. Smith’s Top Five Rules for constructability reviews include the following:
- Build the project; Don’t focus solely on the problems
- Review the Interface of Various Systems
- Keep the Review of Preliminary Documents Constructive
- Stay Focused on the Important Items
- Take the Time to Complete a Thorough Review
Follow the link above or click here to read the full article.
Smith’s recommended approach to a constructability review is to “start at the bottom and work your way up”. That makes a lot of sense. The bottom is not only the lowest part of the structure, it is also the place where new building construction meets existing site conditions (“where the rubber meets the road”). That starting point is where site conditions – possibly concealed conditions – can affect project scope, cost, and schedule. The building design should be based on the best available survey and geo-technical information for the site – including a geo-technical analysis and recommendations for the specific project. In addition to footing elevations and foundation details, construction documents should include clear and coordinated information about foundation excavation, subgrade preparation and required materials, and also a comprehensive approach for dealing with and accounting for unsuitable conditions (e.g., encountered organic materials, ledge, or remains of previous buildings). Terminology for soil materials should be consistent throughout the documents to avoid confusion and to minimize the chance for misinterpretation of intent by bidders; this is especially important when considering graded materials that may need to be imported from off-site. Everyday terms like “gravel” and “fill” should not be used casually on drawings where geo-technical recommendations and specifications include more than one type of each and specific grading requirements for different applications. Unexpected site work change orders can be extraordinarily expensive and lead to unwanted cost cutting and scope reduction in other parts of a project. So, “start at the bottom” is good advice, and it’s also a strong reminder for owners and designers that they need to pay attention to those out-of-sight supporting conditions.