Sealing the Building Envelope – CondoBusiness Magazine

by | Jun 3, 2014 | Knowledge Base

Whether a condominium is a townhome or a high-rise, exterior sealants remain one of the most important components of a building envelope’s good health. Despite this, they are also one of the least understood and maintained components of a building envelope.

The simplest explanation for this might be that sealants are, for the most part, out of sight and therefore out of mind. This is especially true for high-rise condominiums, where much of the sealant is not visible from the ground.

Also, sealants have a long replacement cycle — 12 to 20 years, depending on product and environmental exposure. Many changes are likely to take place at a corporation over that timeframe. Board directors and property managers may come and go; a reserve fund study may recommend a sealant replacement project, but higher priority projects may have to be moved ahead of it. As a result, a condominium’s caulking and sealant needs may get lost in the shuffle.

Unfortunately, sometimes it takes water penetration damage to multiple suites or townhomes to get board directors and property managers thinking about caulking.
An estimated 90 per cent of air and water leakage occurs at one per cent of the building’s sealant locations, i.e. vulnerable sites such as terminations, transitions and penetrations. Making sure that this one per cent of a condominium’s exterior is properly sealed is critical.

For townhomes, properly caulking wood perimeters, trim and siding not only reduces energy costs, keeps moisture and pests out, and minimizes the growth of mould, it also extends the life of the wood as well as the painted finish. With high-rise condominiums, using the opportunity to review and replace sealants while taking care of exterior painting and concrete repairs takes advantage of the staging equipment already in place, therefore helping to keep costs down, minimizing disturbances to residents, and proactively reducing damage, repairs and additional costs.

Due to the length of a sealant cycle, many property managers and board directors may not have much experience with initiating and overseeing a sealant replacement project. Add in the technical nature of the materials and techniques involved, plus the health and safety components (especially with high-rise work), and the whole prospect can be overwhelming for those with limited experience with this type of work.

Property managers and board directors need tools to help them avoid feeling frustrated and disappointed prior to starting the process of replacing sealants. Here are a few basic tips:

    1. Determine when the last time the building or townhome site was caulked. (If past the 12- to 20-year mark, water leaks, wood rot, or other damage issues may have already begun.)
    2. Determine whether the site has been over-beaded or all old sealant

was removed prior to caulking. (Over-beading should only be done once. If a site has already been over-beaded, then full removal is required. If not, then over-beading on failing caulking is an economical option.)

  • Determine the type of sealant currently in use on site. (Inferior products may mean a shorter life cycle.)
  • Make sure all stakeholders understand the specification and any possible limitations of the proposed sealant system.
  • Be sure to work with a qualified contractor, (A contractor’s warranty will cover only a small fraction of the expected life of the sealant, so try to work with someone known and trusted.)
  • Ask to see the contractor’s Health and Safety Plan. (High-rise sealant replacement projects require specialized health and safety expertise and management.)

Sealant replacement is a substantial investment and, if properly executed, will protect the property as well as enhance savings in heating, cooling and repair costs. To realize the full benefits of sealant replacement, the project must be well executed and in a conscientious manner. Short cuts taken 14 storeys up can lead to costly repairs down the road.

Insist on quality sealants. Using low-grade sealants only reduces the lifespan of the system.

Poly-urethane sealants are typically used to bridge joints when at least one of the substrates is wood, masonry, stucco, aluminum, concrete, etc. A good rule of thumb is to specify industry-standard poly-urethane sealants with high mobility properties.

While a certain amount of flexibility exists with how specific sealants are utilized, one hard and fast rule is that silicone should always be used against glass and with all aluminum-to-aluminum joinery. Silicone provides increased adhesion for substrates prone to expansion and contraction. And remember, all silicones are not created equal. A quality product should have proven high performance and exceptional waterproofing properties.

Additionally, directors and managers need to know that silicone is not paintable. If the corporation is considering painting window frames and panels, sealant replacement needs to be coordinated and executed at the same time. There have been instances where sealants have been replaced on a high-rise, only to be removed and re-installed a few years later in order to facilitate the coating of window systems or aluminum panels. This is not only a waste of time, but a considerable waste of money.

Realizing that sealant replacement projects can be costly, property managers and/or board directors should avoid letting price dictate their decision when choosing a contractor or sealant system. Savings realized today are only true savings if the selected sealant system performs for 12 to 20 years. Poorly installed sealants may lead to spot repairs year after year, quickly reversing any savings that may have been generated by proceeding with the contractor with the lowest price.

The sealant on a condominium may only amount to one per cent of the façade, but it’s integral in protecting 100 per cent of owners’ investments in a property. Though these areas account for an extremely small percentage of the building construction, billions of dollars are spent on building envelope repair and replacement. So whether it’s a townhome or a high-rise, it’s important to remember that sealants might be out of sight, but they should never be out of mind.

john_margaritis_2John Margaritis is a Senior Project Manager with ArmourCo: a painting and caulking firm based in Oakville, serving the GTA and Golden Horseshoe condominium marketplace for over 20 years. For more information, visit

This article originally appeared in CondoBusiness magazine. To view a PDF of the original article click here.