Building Envelope: Sealing Out Weather, Sealing in Savings
By Dan Hounsell October 2006 - Maintenance & Operations
Occupants of institutional and commercial facilities tend to pay the most attention — when they think about facilities at all — to the components they can see and the technology they work with.
Generally, however, one the most important components of any facility — the building envelope — gets little if any attention from anyone outside of the maintenance department. But once that envelope leaks and affects equipment, building components, and operations, the hard questions start.
That is why many maintenance managers pay such close attention to sealing the building envelope. They understand that the envelope is a facility’s first line of defense against the elements. Proper specification and application of sealants and coatings keep out the weather and prevent small leaks from becoming big-ticket repair projects.
Sealants and coatings, whether polyurethane, silicone, latex or acrylic, are applied to a host of exterior surfaces around and on institutional and commercial facilities, including masonry, stone, concrete and glass curtain walls. As building envelope materials have evolved, sealant and coating manufacturers have responded with new and reformulated products to address end-user needs.
For example, MS urethanes and other hybrid products have grown in popular over the last 10 years, says Bill McCann with BASF Building Systems. The products offer end users a middle ground between polyurethanes and silicones, he says, in that they tend to be more elastic than polyurethanes and retain dirt less than some silicones.
Also, the nationwide effort over the last two decades or so to minimize and eliminate volatile organic compounds (VOCs) from an array of products, including sealants and coatings, has had a major affect on the latest generation of products. Increasingly, manufacturers have used plasticizers in place of VOCs.
As with most environmental-protection efforts, California has been among the most active states in phasing out VOCs, though it is hardly alone.
“We’re seeing it everywhere across the United States,” says Gwynn Stegen, chief operating officer with Excellent Coatings. The mandate to reformulate sealants and coatings to curtail VOCs has led to occasional compromises in terms of product adhesion and bleedout.
“The regulatory changes can make it hard in some cases to ensure product performance,” McCann says.
Adds Stegen, “We’re seeing good quality products with low VOCs. The reality is, this isn’t going to go away.”
Finally, a number of manufacturers also have introduced products such as paintable coatings, which have been popular in K-12 schools, McCann says.
The selection of the most appropriate sealants and coatings for a project goes hand in hand with determining how the materials will be applied. A manager’s initial impulse might be to use in-house personnel for the job rather than contract it out. But the decision instead should follow a thorough review of key factors, such as the surface’s type and size, the area’s accessibility, the criticality of the surface, and the skill level required to apply the materials. Manufacturers are finding no clear trend within facilities on outsourcing such applications.
“Contractors are doing most of the work, except for small patch jobs,” McCann says. “Anything of any substance is being contracted out.”
Stegen sees the trend moving in the opposite direction.
“We’re seeing a lot more of it going in-house,” she says. “They’re finding they have better control of their destiny and can maintain the building better by doing it themselves. If in-house crews can learn the skills involved, it can help managers stay within thee budget.”
Managers looking to ensure the quality of work they contract out should take a series of steps to evaluate potential contractors, McCann says. Among the steps:
- Find out if the company is affiliated with any professional associations. If so, that is a sign the company has met the business standards of a recognized organization.
- Ask if the company’s workers have taken part in advanced training on restoration products and techniques.
- Ask about other similar buildings the company has worked on, both to see how that work has held up and to talk with managers of that facility about the contractor’s work practices.
Whether the work is handled by in-house personnel or contracted out, managers need to pay attention to important issues that can greatly affect the outcome of the project.
McCann stresses that managers who devote time and attention to an often-overlooked element of sealant application — surface preparation — are far more likely to end up with a long-lasting application.
“It’s absolutely critical to make sure the surface is prepared properly,” he says.
Also high on the list of crucial steps is selecting the right product for the job. Stegen urges managers to devote sufficient time to this component of the project, going beyond simply following a specification.
“A specification is only worth the paper it’s written on,” she says. “It doesn’t do any good unless everybody involved is on the same page.” She encourages managers to consult with sealant and coating manufacturers for in-depth product information and to work with a quality contractor, if that’s the manager’s chosen method of application, instead of taking the lowest bid.
“Manufacturers love to have a real partnership with managers,” she says. “That’s the best way to solve the problem.
The Sealant, Waterproofing and Restoration Institute (SWRI) is a non-profit corporation of 200 commercial contractors, manufacturers and consultants engaged in the application, design and manufacture of sealant, waterproofing and restoration products. SWRI offers educational programs and publications to promote industry-wide standards of application and products.