Brad Blankenship: Components of a Building Mock-up Strategy

Brad Blankenship
Brad Blankenship

It won’t be long before we’ll see more tower cranes circling overhead in Dallas-Fort Worth. As office vacancies begin to shrink, owners and investors will pour hundreds of millions into shiny, new buildings to accommodate the demand. Tenants will, undoubtedly, be confident in leasing these buildings touting energy and space efficiencies, state-of-the-art technology and, wow, even that new-car/building smell. But buyers beware, because there are Frankenstein-like design and construction maladies that can sour the short- and long-term value of your new building.

Ben Franklin said, “A small leak will sink a great ship.” Recently, a popular four star Texas Hill Country resort spent millions re-skinning the resort due to a repetitive mistake with window flashings. Here in Dallas-Fort Worth, a well-known healthcare system also fell victim to similar exterior skin system leaks on a new hospital. The disruption to its hospital operations, impact to patients and guests were surpassed only by hospital management’s fears of potential sick-building syndrome caused by mold and algae growth. The owners blamed the contractor. The contractor blamed the architect, the architect blamed the contractor … you get the picture.

Eighteen years ago, in my first engagement as an owner’s development manager, I had an awful experience with a difficult leak that was occurring somewhere in the exterior wall system. After three months of trial and error and pulling off a quarter of the west façade of the building to find the source of the water leak, we finally isolated the source of the water entry—but not before relocating employees, disrupting business, tearing up landscape, and displacing parking spots during the repairs. I will never forget the frustration of my client and the amount of money the contractor, architect, and I spent determining the source and correcting it all. I was convinced there was a better way and, since then, I follow a strategy that has been 100 percent effective to this date.

Construction mock-ups of exterior façades have been commonplace for centuries. Most architects and contractors use them for reviewing and approving building aesthetics, workmanship and fit and finish. My solution to the leak problem was to use the same mockup approach, but with more attention to the details of how the components go together. We literally design and construct the mockup as a “working laboratory” for rigorous water infiltration testing, bonding of critical sealants, and uncovering and correcting design flaws before they are applied to the real building.

Key components of a good mockup strategy include:

• Proper planning and detailing of the mockup
• Communicate and set expectations with design and construction team members
• Start early on the mockup construction to avoid impact to schedule
• Define progress inspections and frequency
• Photo document progress and problems with fit and finish
• Discuss and agree on testing methods—vacuum and water nozzle testing
• Discover and correct dissimilar metal contact which can lead to corrosion
• Discover and correct problems with the sequence of flashings, end dams and sealants
• Publish “lessons learned” and provide training so that field tradesman learn from the process

The whole process is some amount of science and a lot of hard work. It can be complicated, tedious, boring at times, but always very revealing. The effort has resulted in the complete change of window systems and waterproofing techniques.

The typical investment of a comprehensive mockup can cost $100,000 or more. But it’s a small price to pay to ensure your design firm and contractors are united in their focus to complete a building that does not leak.

Brad Blankenship is managing director of project and development services for Cassidy Turley. Contact him at [email protected]


  • Great article Brad. Mockups should go beyond “the pretty” and should be a study in building D&C. The cost for the mockup is nominal considering the risks involved! Excellent advice!