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Cold Weather Silicone Sealant Application

Building Construction and Cold Weather Silicone Sealant Application
Building Construction and Cold Weather Silicone Sealant Application

Architects, general contractors, and waterproofing contractors face a recurring question every Fall and Winter. Can we use our warm and hot weather silicone sealant for cold weather applications? Yes. Ease of installation, compatibility, and durability are key selection criteria.

It’s all about the chemistry. One-part silicone sealant use atmospheric moisture to assist the curing process. Cold weather decreases the availability of moisture in the air, thus extending sealant curing times. At the same time, cold weather increases the risk of adhesion failure, due to moisture or frost on the joint substrates. Clean, dry, and frost-free joints are one key to successful cold weather silicone sealant application. Ensuring sealant compatibility is another.

Randy McAdams, Senior Outside Sales, Atlas Supply

Cold Weather Sealant Application Glossary

  • Cold Weather Temperature: 5 ℉ above the dew point temperature, typically 40 ℉ or lower
  • Dew Point temperature: The temperature where air is unable to absorb any more moisture. Additional moisture falls as precipitation (rain, drizzle, fog) or condenses on cold surfaces (dew, frost), such as metal substrates.
  • Gunnable: The ability to apply sealant using a caulking gun with normal effort
  • Tooling: The act of shaping sealant already applied in an expansion joint using a caulk spatula to apply pressure and ensure adequate fill of the entire joint width.
  • Cure Inhibition: The result when a chemical, substance or environmental condition inhibits a sealant’s ability to cure properly. Tooling aides such as solvents can contribute to cure inhibition.
  • Silicone Rubber: Any of a class of synthetic materials which are polymers with a chemical structure based on chains of alternate silicon and oxygen atoms, with organic groups attached to the silicon atoms.

Cold Weather Silicone Sealant

Silicone sealant is durable, easy to apply and tool, able to adhere to most surfaces, available in multiple colors. All DOWSIL™ Silicone Building Construction Sealant remain pliable and easy to extrude (gunnable) in temperatures as low as -20 ℉. DOWSIL has 9 sealant rated for cold weather application:

  1. DOWSIL 790 Silicone Building Sealant
  2. DOWSIL 791 Silicone Weatherproofing Sealant
  3. DOWSIL 795 Silicone Building Sealant
  4. DOWSIL 995 Silicone Structural Sealant
  5. DOWSIL 756 SMS Building Sealant
  6. DOWSIL 758 Silicone Weather Barrier Sealant
  7. DOWSIL Contractors Weatherproofing Sealant
  8. DOWSIL Contractors Concrete Sealant
  9. DOWSIL 1199 Silicone Glazing Sealant.

What is sealant compatibility?

Sealant compatibility classifies sealant as chemically suitable or unsuitable to come in contact with other types of construction materials. These products may include weather resistive barriers (WRB), self-adhered membranes (SAM‘s), liquid applied membranes (LAMs) and building cladding. Silicone sealant are fully compatible with other silicone products. Conversely, non-silicone sealant will not adhere to silicone products. We strongly recommended pre-construction adhesion testing of all substrate coming in contact with the specified sealant.

Cold Weather Silicone Sealant Selection

Whether you select silicone sealant depends on the type of project and the climate where you live. Product specifiers and contractors in Western Washington and Oregon seem to gravitate towards silicone sealant because of their ability to adhere to a wide variety of substrates. Silicone sealant , silicone coatings and silicone waterproofing are more common west of the Cascade Mountains, due to the wetter, milder climate.

The Yakima-Tri-Cities Metropolitan Area located in southeastern Washington is one place that prefers silicone sealant. DOWSIL Contractors Weatherproofing Sealant and Contractors Concrete Sealant are competitively priced while still rated for application down to -20 ℉. These two characteristics alone help to explain their popularity.

Sign of Trouble During Cold Weather Silicone Sealant Application

Unseen moisture or frost on the substrate is a typical sign of trouble during cold weather sealant application. Moisture or frost on both porous and non-porous substrates can affect long term adhesion of any type of sealant. It is imperative that you Follow Manufactures Instructions for proper joint preparation in cold weather applications.

Signs of Trouble After Cold Weather Silicone Sealant Application

Adhesion Failure, Movement During Cure, and Adhesive / Cohesive Failure are all signs of trouble after cold weather silicone sealant application.

Adhesion Failure

Adhesion failure can occur for a variety of reasons including improper joint preparation and tooling. Incorrect joint geometry and cure inhibition are also causes for concern.

Movement During Cure

Joint deformation can occur when sealant are applied to cold substrate. Rising temperatures and expanding substrate cause uncured sealant to lose adhesion, wrinkle, or bulge, instead of remaining concaved.

Adhesive / Cohesive Failure

Adhesive failure occurs when a sealant fails to adhere (stick) to the substrate. Causes include dirty, moist, or frosty joint surfaces. Cohesive failure occurs when the sealant splits or tears within itself.

Consult a Cold Weather Silicone Sealant Expert

Cold weather sealant application comes with its own set of challenges, including longer curing times, sealant/joint conditioning, and maximum joint widths. Consulting a cold weather sealant specialist or waterproofing consultant helps you to specify and apply the right sealant. Call your local Atlas Supply silicone sealant specialist today at 1-800-347-5767. Get the help you need to maximize your success and minimize the chance of sealant application/curing failures detailed above.


Randy McAdams, Senior Outside Sales, Atlas Supply

Randy McAdams, Senior Outside Sales, Atlas Supply
Randy specializes in selling waterproofing products throughout the Pacific Northwest for new construction, renovation and commercial repair projects.

Last Modified: July 15, 2021

DOWSIL™ DefendAir 200 Underlies Medallion Apartments Renovation

Architect's Rendering of Renovated Medallion Apartments, Southeast View
Figure 1: Architect’s Rendering of Renovated Medallion Apartments, Southeast View (Source: Holst Architecture)

DOWSIL DefendAir 200 Weather Resistive Barrier (WRB) underlies the Medallion Apartments’ exterior renovations. The apartment building is 6-stories high with 90-unit affordable residential homes, located in Portland’s "Alphabet" Historic District. The Historic Landmarks Commission designated the Medallion Apartments as a non-contributing residential development, because it was built in 1965, well after the historic period. Nonetheless, the building renovation project required Landmarks Commission approval, which concluded:

The proposed exterior alterations and site changes to this existing multi-dwelling development will increase the building’s compatibility with its surrounding historic district and improve and activate the surrounding pedestrian network. The proposed materials are of high quality and the careful details will contribute to the durability of the building.

City of Portland, Oregon – Historic Landmarks Commission

Increase the Medallion Apartments’ Compatibility with its Surrounding Historic District

Prior to its renovation, a failed, stucco Exterior Insulation and Finish Systems (EIFS) dominated the building’s architecture. The stucco EIFS and uninsulated concrete masonry unit (CMU) around each apartment’s entrance contrasted with surrounding Victorian and Federal-style homes.

After renovation, the building’s exterior will be a blend of sand colored, thin brick tile cladding, earth-colored EQUITONE facade panels on the stairwells and cedar plank-inspired fiber cement panels around each apartment’s entrance. The new variations in texture and color will help to soften the Medallion Apartments’ appearance, thus bringing it into harmony with its neighbors.

High Quality Materials Contribute to the Medallion Apartments’ Durability

The use of CMU to construct the Medallion Apartments significantly influenced its renovations.

First, CMU lacks the strength of modern, post-tensioned concrete construction able to support a heavy curtain wall. This limited the choice of brick cladding to lighter thin brick instead of heavier face brick.

Second, CMU is quite porous and requires a WRB to protect against water intrusion. The weather resistive barrier acts like a one-way street for moisture to travel. Water vapor may escape from the building’s interior via tiny holes in the barrier membrane. These same holes are too small for liquid water to penetrate the interior from the building’s exterior. The result is a drier, more comfortable residence, less prone to mold and mildew.

DOWSIL DefendAir 200 Benefits

The key benefits of applying DefendAir 200 include a water-based formula, ultraviolet (UV) stability, primerless adhesion:

  • Water-Based formula enabled easy cleanup of rollers and sprayers using tap water, without gray water retention and disposal, ideal on a space-constrained worksite
  • UV Stable composition allowed the barrier membrane to remain exposed to sunlight after its application, while construction proceeded elsewhere, thus eliminating weatherproofing as a scheduling bottleneck
  • Silicone formula ensured compatibility with DOWSIL 791 Silicone Weatherproofing Sealant
  • Liquid Applied having milkshake consistency using rollers or an airless paint sprayer (Graco® Sprayer or similar);
  • Primerless adhesion to clean CMU or CMU covered with thin-set mortar
  • Quick Turn-Around Time meaning the liquid dries in 2-4 hours and rainwater will run off, if it were to rain later in the day.

Architects are hungry to learn more about the benefits of the next generation of liquid applied air barriers. These benefits include easy water cleanup, indefinite UV stability, and high moisture vapor permeability. DOWSIL DefendAir 200 delivers all of these and more.

Lorne Andrusiak, DowSil-Specialist, Atlas Supply and AIA Continuing Education Provider

Project Challenge: Residual Cementitious Adhesive

Removal of the failed EIFS cladding revealed a unique challenge: residual cementitious adhesive used to glue polyisocyanurate (polyiso) insulation directly to the CMU walls. Mechanical removal of the adhesive proved unworkable, without damaging the CMU substrate. A layer of thin-set mortar proved to be the best solution to bring the CMU to plane and provide a primerless surface to receive the DefendAir 200 Air and Weather Barrier. Figure 2 shows a section of CMU with residual adhesive on the left, a strip of exposed thin-set mortar in the center and roller-applied DefendAir 200 on the right.

North Wall Showing CMU with Residual Adhesive, Thin-Set Mortar and DefendAir 200
Figure 2: North Wall Showing CMU with Residual Adhesive, Thin-Set Mortar and DefendAir 200

Thin Brick Veneer Curtain Wall Details

The thin brick veneer curtain walls are the dominant visible feature of the renovated Medallion Apartments building and include a hidden, careful detail: a moisture drainage plane missing from the failed EIFS. This drainage plane allows intermittent moisture to escape from behind the curtain wall and drain away via a horizontal opening at the bottom of the wall assembly. Figure 3 shows a cross section schematic of the complete wall assembly comprising the following components:

  • CMU Wall
  • Thin-Set Mortar to smooth up to plane (when required)
  • DOWSIL DefendAir 200 Air and Weather Barrier (WRB)
  • RockWool™ insulation mounted on posts and secured with pins
  • Metal furring strips or hat channel used to create an open-air space (drainage plane)
  • WonderBoard® Lite Backerboard with integrated waterproofing
  • Thin-Set Mortar
  • Mutual Materials Slimbrick® Thin Brick Tiles
  • Masonry Pointing Mortar
  • Horizontal Metal Flashing.
Thin Brick Veneer Assembly, Moisture Drainage Plane, RockWool Insulation, WRB and CMU Wall
Figure 3: Cross Section of Thin Brick Veneer Assembly, Moisture Drainage Plane, RockWool Insulation, Weather Resistive Barrier and CMU Wall (Source: Holst Architecture)

The curtain wall, moisture drainage plane and weather resistive barrier work together to ensure the interior CMU wall stays dry.

DefendAir was the right choice for this project because it was able to meet a number of different performance criteria. First, there was the fact that on several elevations, Dow AllGuard had been applied. The DefendAir will both adhere to, and is compatible with AllGuard. The resistance to both air and water infiltration are excellent, and the vapor permeability is right in the sweet spot for our environment. In addition to that, DefendAir offers long term UV exposure, adding flexibility to our schedule, while the water based clean up means we can spend more time installing material instead of cleaning equipment at the end of each day. Finally, we place great value on the partnership and support we receive from both Dowsil and Atlas – they have been long term partners with Walsh in achieving high performance projects for our clients and we knew we could trust them to contribute positively to the team.

Martin Houston, Quality Director, Walsh Construction Company

DOWSIL DefendAir 200 Air and Weather Barrier For Your Next Project

Dow High Performance Building solutions include proven and innovative materials for structural and protective glazing, weatherproofing, insulating glass, high-efficiency insulation, and window and door fabrication. Experience the benefits of DOWSIL DefendAir 200 Air and Weather Barrier on your next weatherproofing project. Call Atlas Supply at 1-800-347-5767 to speak with your team of local weatherproofing experts. Refer to the DefendAir 200 Technical Data Sheet before using this product.


Randy McAdams, Senior Outside Sales, Atlas Supply

Randy McAdams, Senior Outside Sales, Atlas Supply
Randy specializes in selling waterproofing products throughout the Pacific Northwest for new construction, renovation and commercial repair projects.

Lorne Andrusiak, DowSil-Specialist, Atlas Supply

Lorne Andrusiak, DowSil-Specialist, Atlas Supply
Lorne is a Dowsil product specialist and a frequent speaker at The American Institute of Architects (AIA) Lunch & Learn events.

DOWSIL™ Case Study Cornish Commons – Seattle, Washington

Cornish Commons residence hall with unique rainscreen design - Seattle, WA
Cornish Commons residence hall with unique rainscreen design – Seattle, Washington (Used with permission: Casey Braunger / Ankrom Moisan Architects)

A premier college for the visual and performing arts, Cornish College of the Arts’ main campus is located in Seattle’s popular South Lake Union neighborhood, where the 20-story Cornish Commons opened in 2015.

The new residence hall and academic building includes a unique rainscreen design featuring 3/16-inch thick architectural aluminum cladding on cold-form framing. The innovative building design boasts thermal performance 40% better than required by current Seattle Building Code.

Cornish Commons’ Challenge

To achieve its ambitious thermal performance, the rainscreen design includes 2-inch, continuous R-8, exterior insulation to supplement the R-32 interior batt/cavity insulation. But that created additional challenges to be compliant with the Seattle Building Code, which dictates use of insulation outboard of the metal framing. The proposed design needed an air barrier with high permeability to ensure water vapor was not trapped in the wall cavity.

Additionally, staying on schedule – in spite of challenging Seattle weather conditions – was critical. Minimizing product incompatibility issues also was important.

Cornish Commons’ Solution

Ankrom Moisan Architects, Inc. selected the 100% silicone DOWSIL Silicone Air Barrier System to ensure enclosure airtightness performance, durability and compatibility.

When we learned about the option of a fluid-applied silicone air and water barrier, we realized that DOWSIL DefendAir 200 was ideal for our needs. Not only did the spray-applied product simplify installation and eliminate the need for traditional membrane materials, its high permeability ensured our design’s compliance with Seattle Building Code.

Eric Bressman, Architect, Ankrom Moisan Architects

Unitized Construction

To keep the Cornish Commons project on schedule, the design called for a combination of unitized rainscreen panels and traditional construction techniques. The use of unitized panels assembled off-site in a controlled manufacturing environment enabled continued productivity, regardless of weather.

An external cladding contractor’s licensed use of a patented, universal joint system (U.S. Patent 8,943,773) facilitated construction of the unitized panels. This system is designed with interlocking joints that mitigate improper installation conditions that increase the risk of failure.ß The joint system relies on DOWSIL sealants for enhanced performance.

The panels used DOWSIL silicones exclusively: DOWSIL DefendAir 200 as an air barrier and DOWSIL 791 Silicone Weatherproofing Sealant for unit sealing. The quick cure capability of the DOWSIL products helped keep unit assembly on schedule. The unitized rainscreen system was used from the third floor to the 20th floor – using 30 units per floor – with approximately 50,000 square feet protected by the DOWSIL Silicone Air Barrier System.

All-Weather Installation

Construction on-site continued into late fall, due in part to the low-temperature installation capability of DOWSIL DefendAir 200, which can be applied at temperatures as low as 20°F (-6°C).

The ability to use spray-applied product was much easier, said Jerry Jensen, Project Manager. Its cold-weather ability allowed us to continue construction into inclement fall weather.

In addition to the unitized rainscreen panels, on-site work totaling nearly 8,000 square feet used the DOWSIL Silicone Air Barrier System on the first and second floors.

Confidently Build A Better Barrier – Simple. Compatible. Silicones.

Because it is not uncommon to face challenges with varying interfacing construction materials, having a compatible all-silicone solution from Dow was appreciated and advantageous.

Having exclusively silicone products ensured compatibility. Rather than an ‘origami’ of incompatible materials around openings, having all-silicone materials simplified construction and eliminated uncertainty. It is straightforward. We can get answers from a single, trusted manufacturer, without unproductive back-and-forth exchanges with multiple suppliers. It’s helpful to have the continuity and support – and the confidence of warranty protection – from [Dow.]

Jerry Jensen, Project Manager, external cladding contractor

Additionally, the all-silicone compatibility of the DOWSIL Silicone Air Barrier System allowed materials to be applied in any order, eliminating sequencing delays and expenses.

Learn More About DOWSIL Silicone Air Barrier System

Dow High Performance Building solutions include proven and innovative materials for structural and protective glazing, weatherproofing, insulating glass, high-efficiency insulation, and window and door fabrication. Learn more about the DOWSIL Silicone Air Barrier System and other High Performance Building solutions from Dow.


Last Modified: January 9, 2021

Dow Corning® High-Performance Silicone Building Products Are Now Branded DOWSIL™

Dow Corning construction materials are now DOWSIL™. New brand name. Same trusted products.What does Dow Corning Now Branded DOWSIL mean for customers? A new brand name, but the same trusted materials. Continuing warranty coverage. Stronger service and support. A new, easier-to-use website. And a new world of possibilities.

Over the next year, Dow Corning branded silicone building and construction products will move to the DOWSIL name. Product numbers (e.g., “983”) and descriptors (e.g., “Structural Glazing Sealant”) that are part of the product names today will remain the same, and most material numbers and SKUs will not change. Products will be sold through Dow moving forward.

An Integration Information Center is available at Who We Are, where customers can find regular updates, integration activity materials, FAQs, and a tool to generate a chemical equivalency certificates for specific products. More information about Dow’s proven high-performance silicone building solutions can be found at

Download a printable copy of the DOWSIL rebranding announcement [PDF].

Last Modified: August 2, 2020