9 minutes read
Sealants can be a pretty busy component of construction projects.
They operate as a filler for joints and gaps. They repel water and other harmful substances. If necessary, they provide flexibility for natural movement of the structure once complete.
While all sealants can pull some impressive duty, not all sealants are alike. Each has benefits and drawbacks that make that type of sealant the right or wrong choice for a specific environment or structure type.
Let’s review the different types of sealants used in commercial construction and their best-use scenarios, so you can make the right choice for your project.
The Basics of Commercial Sealants
Commercial construction-grade sealants must stand up more human, vehicle, and equipment traffic than the types a homeowner might use. There’s also a greater variety of substrates the commercial contractor must deal with, some of them challenging.
With this in mind, it makes sense to understand the requirements for sealants to be considered construction-grade:
- Allow a certain amount of movement in the joint/gap
- Resist environmental threats
- Work well with adjacent materials
6 Types of Construction Sealants
Common types of construction sealants include:
- Silicone
- Polyurethane
- Butyl
- Epoxy
- Acrylic
- Latex
Silicone Sealants
Silicone sealants are popular in commercial construction due to its many benefits and the wide variety of products available. These sealants are a common partner for glass, metal (including stainless steel and aluminum), concrete, plastic, and wood. You can also use them on stone and stucco.
However, the benefits of the various types of silicone sealant come with extra cost. You are, after all, paying for quality and a 20-year lifespan.
Benefits include:
- UV resistance
- Resistance to moisture
- Chemical resistance
- High adhesion strength
- Offers permanent flexibility, even at extreme temperatures
- Doesn’t shrink
- Resistant to mold
Drawbacks of silicone sealants include:
- Most can’t be painted
- Can stain certain substrates
- Strong odor
- High cost
Common commercial applications of silicone sealants include air gaps in buildings, waterproofing and insulating floors, and around windows and doors.
Polyurethane Sealants
Polyurethane sealants are best for applications that require high strength and resistance to abrasion and chemicals. These sealants have great adhesion with good movement capability, though they’re not quite as flexible as silicone products. Its durability is middle-of-the-road, lasting about 10 years on average.
Polyurethane products bond well to wood, metal, and plastic. Sadly, they don't work well with glass.
Polyurethane sealants come in tinted hues like gray, black, or white for matching or complementing the surrounding materials.
Benefits include:
- Watertight
- Good performance at a moderate price
- Resistant to chemicals, weather, and oil
- Stand up to abrasion
- Adhere well to surfaces with little preparation
- Easy to clean
Drawbacks of polyurethane sealants include:
- Difficult application and tooling
- May be too rigid at low temperatures
Common commercial applications of urethane sealants include general industrial, exterior walls of buildings, pipes, ducts, and mechanical components.
Butyl Sealants
Butyl sealants are synthetic rubber materials that demonstrate a strong adhesion to a wide variety of materials, including metal, glass, concrete, and timber.
Butyl doesn’t fully cure in the way other materials do, presenting some unique pros and cons.
Benefits of applying butyl sealants include:
- Flexibility
- Adherence to a variety of materials
- Forms a tough skin but remains permanently plastic underneath
- UV- and moisture-resistant
- Withstands vibration
- Low price
Drawbacks:
- Lifespan is 5-10 years
- Difficult to apply
- Attracts dirt & dust
- Poor elastic recovery and can permanently deform
- Can’t be painted well
Common commercial applications of butyl sealants include roofing, below-grade applications, curtain wall joints, door frames, drains, and windows.
Epoxy Sealants
Epoxy sealants are famous for being ridiculously strong. They’re also the most rigid products out there – to a (literal) fault, depending on the application. If you use them wisely, they can last 20-30 years or more.
These sealants are compatible with a variety of materials, including concrete, wood, metals, and some plastics.
Benefits include:
- Cost-effective
- Water-resistant
- Chemical-resistant
- Easy to clean
- Physically durable (i.e. mechanical stress, abrasions)
- Also can act as adhesive
Drawbacks:
- Limited movement capability – they crack under thermal or structural stress
- Long curing time
- Require surface preparation
Common commercial applications of epoxy sealants include concrete repair, bonding and coating, and anchoring (railing rebar, bolts in concrete). They’re particularly useful in floors, walls, and foundations for crack repair or anchoring.
Acrylic Latex Sealants
Acrylic sealants, such as latex, are solvent-based and versatile products. Think of them as a budget option for not-so-heavy-duty work indoors.
These sealants are compatible with concrete, wood, and drywall.
Benefits include:
- Fully cure in 1-2 days
- Environmentally friendly (give off fewer VOCs)
- Easy to apply and clean up with water,
- Paintable, allowing you to keep the aesthetic spirit
- Reasonable price point
- Act both as adhesive and sealant
- They don’t offend your nose
Drawbacks:
- Need warm and dry environment to cure
- Shrink upon drying
- Not water-resistant
- Short general lifespan
- Inflexible and can crack over time
Most common commercial applications of these sealants are inside a building. They include trim and molding, drywall and plaster repairs, gaps around doors and windows, and paintable surfaces.
Types of Sealant Used in Construction: Does Format Matter?
Sealants come in various forms and can be applied using different methods. Different sealant forms provide unique benefits (like skipping the mixing step or thriving in tough conditions). Common varieties include:
- One-component
- Two-component
- Tape
- Spray
One-Component
One-component sealants are generally ready-to-use in a single package (cartridge, tube, or sausage) and cure upon exposure to moisture in the air. They’re easy to apply because there’s no mixing required, but that shortcut also means less strength compared to two-component types. This makes them a better choice for quick repairs.
Using one-component sealant means the mixture is uniform upon arrival; this reduces the risk of uneven ratios or application issues. These sealants also have a longer shelf life, even after opening them, compared to two-component varieties. This can change, however, based on exposure to heat, moisture, or UV.
Example: Dow 790
Two-Component
Two-component sealants arrive in bulk containers separately. The upside here is they offer stronger bonds. The downside? They’re more complex to apply and require you to mix them first.
Some installers use a less-common option that involves a dual-cartridge system that can mix the components during application.
Two-component sealants cure through a chemical reaction. The process doesn’t require specific conditions, so two-component products are great in unpredictable environments. This improves predictability for work times and makes these the preferred sealant for high-performance applications.
Adjusting ratios and formulations allows you to meet specific performance requirements. Two-component sealants are generally used for larger projects, such as professional waterproofing.
Example: Sikaflex-2C SL Polyurethane Elastomeric Sealant
Tape
Tapes are typically made of flexible materials like rubber, silicone, or foam and come in rolls or strips.
Tape isn’t just an adhesive. In construction, it works as a seam and joint sealant against:
- Air
- Moisture
- Chemicals
Tape works well for immediate sealing needs because it’s easy to apply and doesn’t require curing. Sealant tape can provide a neat finish as well, but isn’t so great as a heavy-duty product.
Example: 3M VHB Tape GPH-160
5 Different Types of Sealant Based on Job Environment
Different structures require different levels of protection. For example, some buildings are constructed to house businesses that require less outside sound to trickle in. Others require mildew-resistant sealants, due to the humidity of the location.
Let’s look at the external factors you’re most likely to come across:
- Acoustical
- Paintable
- Nonstaining
- Mildew-resistant
- NSF
1. Acoustical
Certain types of silicone sealant provide an acoustical benefit, reducing the sound that passes through the gaps in walls and floors. Flexible and paintable, this type of sealant is for (mostly indoor) use on various materials, including:
- Aluminum
- Brick
- Concrete
- Marble
- Metal
- PVC
- Stone
- Wood
Masonry is a common use case.
Acoustical sealant is generally mold- and mildew-resistant and stands up to UV rays. Keep in mind that any silicone sealant is also waterproof and non-shrinking.
2. Paintable
For aesthetic builds, you may want the joint or crack to match the adjoining surface. This requires sealants that allow paint to adhere, making the surface one uniform color.
Acrylic is the most common material choice for these sealants, although some polyurethane products are paintable too. Silicone-modified acrylic sealants combine the paintability of acrylic with some of the flexibility and durability of silicone.
3. Nonstaining
Decades-old buildings still need to look presentable. Over time, fluids and oils can migrate into materials like marble and other stone. When that happens, you can’t get it out, and the look of the historic building is history.
These products have passed a warranty test proving they prevent the migration of oils and other fluids that stain.
4. Mildew-Resistant
Surfaces that are regularly exposed to water can host mildew. This ranges from showers and bathrooms to pool surfaces, which typically aren’t exposed to sun or breezes. Special resistant sealants do their part in reducing the build-up of mildew in these areas.
5. NSF
Commercial kitchens and other food facilities require sealants certified by NSF (National Sanitation Foundation) International. These sealants are minimally toxic and won’t cause illness if they find their way into foods. Stick to NSF-certified sealants in areas where food preparation occurs and around refrigerator seals.
Types of Sealant: Tips From Mixture to Application
Sealants are available in a variety of types to provide the right amount of water resistance and other characteristics needed to give the structure a longer life expectancy. With the variety of application methods and specialty products, the choice of the best commercial sealant takes time and education.
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