[Product Focus] Need Sealant That’s Paintable & Durable? Go Hybrid

Thanks to hybrid technology, contractors can combine two high performers – polyurethane and silicone – into a single hardworking tag team.

DOWSIL Contractors Paintable Sealant (CPS) is a popular choice for a diverse range of commercial and residential building work. Unlike many other construction products, CPS’ versatility doesn’t mean a tradeoff in performance or quick curing. The sealant is paintable just like you’d expect with urethane, but adds some of the toughness of silicone.

Welcome to the first-ever edition of our Product Focus series, where we demystify construction materials in the Garvin distribution catalog. We’ll give you an exclusive, yet objective look at what makes DOWSIL paintable sealant great, where to use it, and when to avoid it.

By the Numbers: DOWSIL Contractors Paintable Sealant

• Product: DOWSIL Contractors Paintable Sealant
• Type: Joint sealant
• Manufacturer: Dow
• Material: STPE hybrid (silyl terminated polyether)
• In a Nutshell: The best features of silicone (flexibility) and polyurethane (paintability) in one high-performance sealant

This sealant is part of the DOWSIL branded family of products from Dow Silicones. (Dow + Silicone = DOWSIL … Get it?) The maker, also formerly known as Dow Corning, specializes in silicone-based products. The DOWSIL line consists of sealants, adhesives, thermal management materials, and more.

Dow’s Contractors Paintable Sealant is a one-part, neutral-cure product. It consists of some silicone, some polyurethane, and medium movement capability.

As you’ll see, these traits don’t mean the product is average. Far from it, with the proper application.

Benefits of DOWSIL Contractors Weatherproofing Sealant

What makes Dow’s CPS one of the best paintable sealants? There are six ways it stands out vs. everyday commercial sealants.

1. Movement Capability

While it’s not the best of the best, DOWSIL CPS’ expansion and contraction range of 50% (in either direction) is plenty impressive. The elasticity of this sealant makes it ideal for joints that experience moderate movement from thermal expansion or structural shifts.

It’s more than you’ll squeeze out of standard, urethane-only sealants.

2. Great Aesthetics

Unlike other commercial silicone sealants, DOWSIL CPS is paintable. Once dry, the product is compatible with most industrial and consumer paints made from latex or acrylic.

(Pro Tip: Test the paint’s compatibility prior to using it on the job.)

Perhaps best of all, the product is non-yellowing and non-staining.

With visual versatility, the product is great for retrofitting work. Dow allows buyers to choose from several looks to ensure a seamless fit:

• Black
• Bronze
• Special Bronze
• Charcoal
• Gray
• Tan
• Precast white
• White
• Anodized aluminum
• Limestone

Check with your distributor to see which colors are readily available.

3. Defies Gravity & the Need for a Primer

As a hybrid adhesive sealant, CPS offers primerless adhesion on most common nonporous surfaces, plus many porous substrates. DOWSIL contractor sealant works with:

• Concrete
• Masonry
• EIFS (exterior insulation & finish systems)
• Aluminum
• Steel
• Wood
• Vinyl
• Plastic

This reduces the number of steps in the installation process, saving time and labor expenses.

As for the adhesion itself? As you know, gravity can cause a construction material to droop or run, which can result in uneven application or a compromised seal. DOWSIL CPS is a non-sag sealant, meaning it has a thicker consistency that allows it to stick better to surfaces. You can use the product in vertical and overhead joints without worrying about slumping or running.

This is particularly important when applying the sealant to joints and gaps that are:

• Vertical
• Overhead
• Around windows and doors

Dow’s hybrid silicone achieves this without the need for extra support or reapplication.

4. Cures Quickly

Unlike many one-part sealants, which require a long curing period before you can coat them, DOWSIL CPS is paintable almost immediately. 

Tack-free time is 30-60 minutes (at 77°F and 50% relative humidity). Combined with the final cure timeline of 1-2 weeks, Contractors Paintable Sealant gets you through on-site work more quickly.

5. Durable

Dow’s paintable sealant is built for all climates. It’s not just the wide application temperature range. It’s also the fact that, once you install it, it’ll thrive in climates from -75 to 300°F.

The CPS formula has other features that give it a solid lifetime value:

• Excellent UV protection
• Weather resistance
• Doesn’t corrode nearby materials

Pure polyurethane products tend to last only half as long, about +/-10 years.

6. Eco-Friendly

Looking for your construction site materials to contribute to your sustainability efforts? Contractors Paintable Sealant uses a low-odor, low-VOC (volatile organic compound) formula. It meets VOC limits for sealants anywhere in the United States.

Especially important for indoor work, low-VOC silicone/polyurethane sealants reduce health risks while providing a pleasant atmosphere. Try CPS out in enclosed or poorly ventilated spaces. (If nothing else, passers-by will appreciate the lack of stench.)

When to Use (& Not Use) Dow Paintable Sealant

At a high-level view, it’s simple to recognize the use cases for a product like DOWSIL CPS. It’s a logical choice when paintability is a must, but not at the expense of structural integrity.

Dow intends for contractors to use CPS for weather-sealing: 

• Frame-to-structure and perimeter caulking – i.e. windows & doors
• Dynamically moving joints – i.e. expansion & control joints
• Siding – i.e. precast concrete panels
• Molding & trim
• Roofs & gutters
• Vents & ducts

In short, DOWSIL’s product has uses for both heavy- and light-duty commercial building. It’s also viable in high-end residential construction, where aesthetics may be just as important as functionality.

Avoid This Product When …

Despite all these benefits, there are a few markets and construction environments where CPS is a no-go.

Don’t use DOWSIL Contractors Paintable Sealant when the surface is:

• Below-grade
• More than 122°F during installation
• Teflon, polypropylene, or polyethylene
• Wet or frost-covered
• Prone to bleeding oils, solvents, plasticizers
• Using green or partially vulcanized rubber gaskets or tapes

There are also industries where the environment or lack of testing confirmation make CPS use a bad idea:

• Medical
• Pharmaceutical
• Food
• Submerged installations

Basics of Applying DOWSIL Paintable Sealant

Still with us? DOWSIL paintable joint sealant might be perfect for your next project, though proper installation still matters. Here are some starting points:

• Preparation – The joint must be dry and free from oil, loose mortar, water-resistant products, and any other contaminants. You may need a solvent, wire brush, grinder, or sandblaster to achieve a good-as-new surface.
• Priming – Contractors Paintable Sealant doesn’t need a primer for most surfaces, including other cured Dow silicone sealants. If you do need priming, the manufacturer recommends DOWSIL Primer P for porous substrates and DOWSIL 1200 OS Primer for nonporous surfaces.
• Masking (optional) – Cover areas adjacent to joints to ensure neat sealant lines. Don’t allow the tape to touch clean substrates on which the sealant is to stick. Remove the masking immediately after tooling.
• Application Method – Install the backer rod, joint filler, setting blocks, spacer shims, etc. Load the sealant in an appropriate applicator – most air-operated guns and bulk-dispensing equipment will work. Apply the sealant continuously, using positive pressure.
• Tooling – Complete this in a single stroke immediately after application and before a skin forms on the sealant. Use a concave-profile tool and light pressure spread the sealant against the backer and joint surfaces.

But Is It the Best Paintable Sealant for You?

DOWSIL Contractors Paintable Sealant is a fast-curing, non-sagging, elastomeric sealant that tacks on visual benefits to boot. CPS is paintable as soon as it’s tack-free, making it useful in architectural projects where precision and neatness are musts.

Check your specs and job site conditions before picking any construction material or sealant. From there, verify the product’s compatibility – and availability – with a distributor.

Of course, there are many other great products in the Dow lineup and at other manufacturers. To see a full list of suppliers Garvin carries, click below: