2014/2015 Cold Weather Application Guidelines

Cold temperatures change the physical properties of adhesives, sealants, primers, and coatings and alter the handling characteristics of roofing membranes due to increased rigidity. The information provided below is intended to help the installer successfully apply Firestone roofing materials in cold weather.

 

ROOFING AND WALL CAVITY ADHESIVES, SEALANTS, PRIMERS AND COATINGS

A.  Storage
All adhesives, sealants, primers and coatings must be stored between 60 °F (15.6 °C) and 80 °F (26.7 °C) prior to use, in order to ensure proper mixing and dispensing of the product and to ensure an appropriate application rate. If the properties and application characteristics of the materials begin to change during cold weather application, restoring them to room temperature will be necessary. Materials that have been stored below 60 °F (15.6 °C) need to be brought up to room temperature, thoroughly mixed and then examined for proper blend (no marbling or separation of components) prior to application.

Never allow water-based products to freeze (Water Based Bonding Adhesive P; SA Water Based (WB) Primer; AcryliTop™ PC-100 coating and Base Coats; Industrial Elastomeric Coatings and Base Coat). Freezing of water-based products renders them permanently unsuitable for use.

B.  Cold Weather Dispensing
When liquid materials are cold, their viscosity increases causing solvents and solids to separate. This separation of the solvents can make mixing and dispensing very difficult. Refer to the Technical Information Sheet (TIS) for each individual product for their minimum application temperature at the time of installation. Be sure to reference and follow all local Air Quality Management Districts’ requirements for application temperatures.

To minimize the potential for materials cooling on the roof before application, follow these additional guidelines:

  • Only bring materials from their warm storage within 1 to 4 hours of their application or as necessary to ensure dispensable material is close to 60 °F (15.6 °C).
  • Always thoroughly mix adhesive, primers, and coatings to a uniform, smooth state before and during use. Follow mixing instructions provided with each product and do not use any mixing equipment that could generate a spark, which could ignite flammable material.
  • Keep adhesives, sealants, primers, and coatings as close to 60 °F (15.6 °C) temperature as possible during application. In extreme conditions it may be necessary to rotate material between a hot box or warm storage area and the roof during application in order to maintain appropriate application temperature.

Drying times depend on ambient conditions; cool and overcast conditions will lengthen open times, while sunny and dry conditions shorten open times. Expect and plan for longer open times in cooler weather. Solvent blisters can occur if membrane is mated while the solvents in the adhesive/primer are not sufficiently dried.

C.  Application
To compensate for ambient conditions, additional time may be required for solvents to properly flash-off prior to adhering insulation or membrane. This applies to all primers and adhesives. During cold temperatures, a false reading may be given if a “touch-push” test is not performed properly. Be sure to conduct the “touch-push” test in the area(s) with the heaviest application of primer or adhesive and be sure to use a clean finger with adequate pressure to verify that all the solvents have flashed-off. Additionally, some products may not be verified by a “touch-push” test, but rather by time. Be sure to refer to the Firestone website for the most current TIS for all products being used on a cold weather job for proper application instructions.

Do not apply water-based products if freezing temperatures are expected within 48 hours after application to prevent disruption of the assembled materials while the assembly is transitioning from a green bond to full strength.

D.  Solvent Evaporation Rates
The chart below shows the various flash-off times associated with the solvent components of our adhesives, sealants, primers, and coatings. Our products may contain one or more of the solvents listed below. Because of the various formulation ratios of solvent components in each product, we cannot specifically assign a flash-off comparative value per product. Referencing the specific product’s Safety Data Sheet (SDS) for chemical components and comparing that information with the table below will provide some idea of what to expect regarding flash-off efficiency. Ambient conditions will affect all solvent flash-off times, but the affect will be proportional. To achieve Low Volatile Organic Compound (LVOC) status, materials must use highly engineered solvents that meet rigorous environmental criteria.

Solvent Chart
*The standard reference for Evaporation Rate is n-butyl acetate with evaporation rate of 1.0.

E.  Adhesive “Blushing”
“Blushing” occurs when the evaporative cooling of the material during dry time lowers the surface temperature at or below the dew point, resulting in condensation formation on the adhesive/primer film. When “blushing” occurs, the condensation on the adhesive/primer will not permit proper adhesion. The use of adhesives/primers should be monitored closely when the ambient temperature is relatively close to the dew point, keeping in mind that these temperature gaps are typically much narrower in the early morning and late afternoon. The use of adhesives/primers should be scheduled for midday to take advantage of the best adhesive application conditions of the workday, i.e. midday sun and the greatest difference between ambient and dew point temperature.

F.  Hot Asphalt
Application of SBS and BUR membranes in hot asphalt at ambient temperatures below 40 °F (4.4 °C) requires special handling and application techniques. Cold substrates can cool mopping asphalt at a rapid rate. Asphalt cools and thickens more quickly as the temperature decreases and will not flow well, and may fail to yield a uniform application rate.

The following cold weather application procedures are to be used when the temperature at the time of application is below 50 °F (10 °C):

  • Firestone Building Products does not recommend the use of hot asphalt when the outside temperature is below 32 °F (0 °C) or when wind speeds exceed 10 miles per hour at ambient temperatures below 40 °F (4.4 °C).
  • All asphalt handling equipment should be insulated in order to minimize the drop in asphalt temperature prior to application.
  • Roofing membranes should always be stored between 50 °F and 100 °F (10.0 °C and 37.7 °C).
  • Materials must be used within 4 hours of removal from a heated storage area.
  • If materials are not used within 4 hours they must be returned to a heated storage area until they return to 50 °F and 100 °F (10.0 °C and 37.7 °C) in temperature. The time required for roofing materials to return to the proper temperature for use is typically 24 hours.
  • Mop lead should be reduced to no more than five (5) feet (1.5 meters) from the roll.
  • Roll cap sheets into hot asphalt using positive pressure, ensuring proper side and end lap width.
  • Asphalt temperature shall be of 420 °F (215.6 °C) minimum, and must be maintained at the point of application of the roofing membrane.
  • Stop the operation and/or change to another container when asphalt temperature, at the point of application, cannot be maintained at 420 °F (215.6 °C).
  • Never overheat asphalt to compensate for cold weather conditions, and never heat asphalt above its final mopping temperature or its flash point. Always remain within the asphalt manufacturer’s approved application range, but never below 420 °F (215.6 °C).

Always follow all OSHA and NRCA safety regulations.

G.  Firestone Multi-Purpose MB Cold Adhesive and Flashing Cement

  • Multi-Purpose MB Cold Adhesive is best applied in cold weather by use of a heated spray rig. Squeegee-applied Cold Adhesive in temperatures below 40 °F (4.4 °C) is not recommended. Ambient and substrate temperatures should be 40 °F (4.4 °C) and rising at the time of application. Installation in temperatures colder than 40 °F (4.4 °C) should only be attempted when the adhesive pails are maintained at 60 °F to 80 °F (15.6 °C and 26.6 °C) until immediately prior to application.
  • Firestone Multi-Purpose MB Flashing Cement should only be used when ambient and substrate temperatures exceed 40 °F (4.4 °C) and rising.

 

ROOFING MEMBRANES

A.  Membrane Size
During colder weather, folded membrane panels become more difficult to relax and install, especially with adhered systems. The use of no-fold panels is highly recommended. Always unfold single ply membrane panels and roll out modified bitumen and BUR rolls in order to allow the membranes to fully relax prior to installation.

B.  UltraPly™ TPO Installation
To ensure that seams are properly welded when using an automatic welder, it is critical that test welds are done: 1) at daily start-up, 2) whenever ambient conditions change, and 3) if welding is stopped for a significant period of time (lunch breaks, etc.). When using a hand welder, test welds should be performed on scrap membrane or flashing material to ensure that the operator is using the proper technique and temperature setting.

TPO membrane can become stiffer in colder temperatures. To help relax TPO membrane and increase its flexibility, remove the white wrapping on the roll early in the day that the membrane will be installed and leave the roll in the sunlight as long as possible before installation. This will enable the dark bottom ply of the TPO membrane to absorb as much heat as possible and help the TPO membrane to relax and become more flexible.

C.  RubberGard™ EPDM Flashing Installation
Uncured EPDM flashing products are designed to be formable during warmer temperatures, but in cold weather, supplemental warming may be needed. This warming can be achieved by using a heat gun during application. Care should be taken to keep any heat gun away from cleaners, primers, adhesives, or other flammable materials. Ambient conditions (sunlight, wind, and temperature) and flashing color will determine the need for supplemental heat. Typically, temperatures below 60 °F (15.6 °C) may require the use of an additional heat source to ensure the formability of uncured flashing products.

D.  SBS, APP and BUR Installation
SBS and APP modified bitumen products and BUR ply felts should be stored between 50 °F and 100 °F (10.0 °C and 37.7 °C) and installed when ambient and substrate temperatures are 40 °F (4.4 °C) and rising. Attempting to install these asphalt-based products in colder temperatures can reduce adhesion and cause disbonding or blistering during subsequent heating cycles.

 

VAPOR BARRIER AND UNDERLAYMENTS

A.  Air and Vapor Barrier
Enverge™ Air and Vapor Barrier SA (40 mil) and SA-Solvent Based (SB) Primer have a minimum installation temperature of 14 °F (-10 °C). Enverge™ Air and Vapor Barrier SA (25mil) has a minimum installation temperate of 50 °F (10 °C). V-Force™ Vapor Barrier Membrane can be applied at ambient temperatures as low as 25 °F (-3.8 °C) as long as V-Force membrane has been stored in a heated area so that it will be between 50 °F to 100 °F (10 °C to 37.7 °C) at the time of application.

B. Underlayments
CLAD-GARD™ SA and CLAD-GARD R underlayments have a minimum application temperature of 40 °F (4.4 °C) at the time of application. All material should be stored out of the weather in a clean, dry area, in its original unopened packaging.

For further information and assistance please contact Please contact Quality Building Services Technical Department at 1-800-428-4511 for further information.

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