Facilities (Campus Spaces)

Waterproofing Keys

• By Mark Rowh
• 12/01/16

An effective building envelope is a basic need for every facility. Maybe bad weather can’t be avoided, but it can be kept outside. In protecting everything from roofs, walls and insulation to windows, doors and skylights, adequate waterproofing is a key, especially in the higher ed setting.

“While building envelope and waterproofing play a large role on any project, college and university buildings have longer lifespans that make this even more of a necessity,” says Frances Gooding, a project architect with Stantec, an engineering, consulting and design services firm in Plano, TX. She says that intermittent leaks that aren’t especially destructive in a 15-year commercial building can create havoc in a 50- to 60-year building. Due to longer life spans, the materials selected to perform the waterproofing function must last the life of the building.

Such concerns may take on even more importance given ongoing budget pressures.

“As operating budgets continue to stretch thin, college and university management and organization groups are expected to do more with less,” says Kevin Donaghey, project architect at HGA Architects and Engineers in Los Angeles. “As a result, the practical aspects of building performance, maintenance and longevity are becoming increasingly prominent in the design conversation, with new facilities striving to be self-sustaining and operate on minimal resources.” He notes that while it’s essential for buildings to be equipped with weatherproof exterior enclosures that maintain their efficacy over the life of the building, this should not be done at the expense of design excellence. Donaghey points to a common misconception that the likelihood of water intrusion is directly related to the complexity of the exterior enclosure, and that a simplified building mass is an effective strategy to combat potential water intrusion.

“While material transitions and ins/outs of the building façade can provide unique weatherproofing challenges, proper detailing and installation can allow for a dynamic façade without increasing the risk of water intrusion,” he says.

Certainly when problems in this area occur, they can pose serious challenges. Kris Linster, national BECx team leader, facilities services, with engineering and testing services company Terracon in Jacksonville, FL, says moisture intrusion is routinely one of the top sources of warranty callbacks, rework and construction litigation.

“This goes to show this is a significant issue regarding the built environment and has overwhelming impacts on the spaces where we learn, work and play,” he says. “At the level of higher education, the way that moisture intrusion is uniquely destructive is in disruption of classroom and lab activities.”

Water penetration can damage valuable equipment inside the building, and also can also make the exterior of the building less visually appealing, according to Teddy Williams, assistant regional business development manager with Western Specialty Contractors in Dallas, TX.

“The building envelope also affects the energy consumption of the building,” he says. “A properly maintained building envelope will have significantly lower energy costs.”

Sustainable Approaches

As with other elements of facility maintenance, sustainability is an ongoing consideration when to comes to the building envelope and waterproofing.

“Water is often referred to as the universal solvent because it can be deleterious to such a variety of substances,” Linster says. “When it comes to sustainability and resiliency, everyone is attempting to use materials and products that have longer lives while prolonging the life of already good materials.” Once materials are selected and installed, including sustainable ones, they naturally begin to deteriorate, he says. Catalysts such as rain events and gravity play unavoidable roles in this process.

Indoor Environmental Quality is a key component of the LEED system for sustainable design, and moisture levels within the building play an important role, according to Donaghey.

“The ability of indoor humidity to be maintained within an acceptable range throughout the life of the building is greatly enhanced with an effective weatherproofed enclosure,” he says.

“At the extreme end of the indoor environmental quality spectrum, unwanted moisture can result in hazards such as toxic mold, posing potential harm to building occupants, and potential litigation to building owners.”

Donaghey notes that sustainable site features such as rainwater detention systems and bioswales can help divert water away from the building, serving as a more effective preventative measure than stopping water at the building enclosure. Too, the selection of waterproofing products can contribute toward credits in the LEED materials and resources category.

Due Consideration

Of course local conditions merit consideration, but water can pose problems virtually anywhere.

“We’ve encountered contractors in southern California who have a relatively casual attitude towards waterproofing, pointing out that it ‘never rains here,’ and that comprehensive waterproofing on exterior assemblies is less important than in regions with greater rainfall,” Donaghey says. “However, even the driest of climates are susceptible to spouts of torrential downpour and water intrusion.”

He adds that understanding how rainwater behaves, and being able to visualize the multitude of rain and wind combinations that a building could be exposed to, is vital in developing details that will stand the test of weatherproofing.

“The best approach is to always view exterior assemblies through the lens of worst-case-scenario rain conditions,” Donaghey says. “This can require a bit of imagination while visiting a dry and dusty construction site in July, but it will help ensure that rainwater stays outside the building, where it belongs.”

Linster says that the best dollar-for-dollar method of providing a well-protected facility is Building Envelope Commissioning (BECx). This process covers all aspects of the life of a project from design and product submittal reviews, to construction installation monitoring and system performance simulation, to ongoing warranty reviews.

“The typical cost of BECx is orders of magnitude less expensive than the cost of recladding a building after an issue with moisture intrusion with returns on investment of up to one thousand percent,” he says. “BECx is most certainly the best insurance policy that owners can take out on their facility.”

Donaghey advises specifying requirements in the front-end specifications for the contractor to protect exterior openings from rainwater intrusion during construction prior to completion of the exterior enclosure, as well as always having proper storm water prevention provisions in place. He reports that his firm has encountered instances with several recent projects where unanticipated rainstorms during the dry season caused extensive flooding of the construction site and water intrusion of the unfinished envelope, due to inadequate protective or preventative measures by the contractor.

“Extensive water testing is a key to verifying the exterior assemblies of glazing systems, and if possible, should be performed on a mock-up installation before the assembly is installed throughout the project,” Donaghey says. It can also be helpful to establish expectations with the contractor that waterproofing matters aren’t fully resolved until the building survives at least one major rainstorm, which can often help in identifying potential intrusion points.

This article originally appeared in the issue of .