Cold weather brings additional challenges for the spray foam contractor. These challenges are easily addressed, but not easily remembered until the contractor begins to experience the issues which are always present during cold weather application The first issue is being aware that the temperature is about to change, and ordering the appropriate reactivity product to address the upcoming change. Below is a chart showing the lower end of the application range for each product.
When spray applied polyurethane foam is applied in colder conditions than intended for the formulated reactivity, the results can include a smooth glossy surface, friability, poor yield, and poor adhesion. There is some ability, although limited, to adjust for fluctuations in temperature. Often referred to as “dialing in” a foam during the application, the applicator can adjust the preheats and hose temperatures as well as the pressure of the proportioning unit.
The proper storage of both components is critical for a successful application during cold weather conditions. Both components must be at a minimum of 70°F to insure that the supply pumps can move the material to the spray machine at an appropriate rate. Both materials will thicken as they cool. The resin or “B” side will get very thick and hard to pump very quickly as the temperature drops below 70°F. In addition, depending on the machine being used, some machines may not have the capability to heat the material to the required application temperature.
Each machine is only capable of producing a specific amount of heat. If the temperature difference between the beginning temperature of the material and the required temperature for application is greater than the machine can supply the result will be poor foam quality. This may also cause off ratio foam, down time and may damage your equipment.
As always, please do not hesitate to contact your Lapolla salesman or technical staff with questions of field application issues. Once you are on the job, should problems occur, you risk down time. As we all know, if the applicator is not spraying foam, nobody is making money.
Here are some additional tips for successful cold weather spray foam application.
Warm up the substrate as much as possible before spraying. Torpedo heater can be used prior to spraying, however, all open flame heaters must be turned off while you are spraying. Please remember that the use of propane and gas fired heaters will result in high humidity levels. This humidity may condense on cold substrates creating moisture issues such as poor adhesion or shrinkage. Applicators should avoid the use of gas fired heaters if possible to reduce this risk. Blocking soffits and exterior penetrations will help retain some of the heat.
Keep the hose off the snow, ice, and concrete. These will draw heat off the hose as fast as the proportioner can heat it.
Use the sun to your advantage. The sun is the largest heater you have. Start spraying on the sunny side and follow the sun around through the day.
Whenever possible, maintain heat in the area for 24 to 48 hours after spraying to help with the curing process.
Order you materials far enough in advance to give them time to warm up (about 10 degrees per 24 hours). Do not store drums in direct contact with concrete. Keep them on the pallets while in storage. When the materials are in the truck, place something under the drums to raise them an inch or two off the floor to allow warm air to circulate underneath them.
Do not allow the dynamic pressure to drop below 1000 psi. Pressures less than 1000 psi can result in a poor mix in the gun.