Spray Foam Dry Time

During a time when energy-efficient projects are on the rise, using spray foam to insulate your building is an ideal way to play your part. The installation process is quick and straightforward. 

Assuming installation was done correctly, you can expect your spray foam to cure in 24 hrs. However, many factors affect this process, meaning the dry time will change respectively.

Factors that Affect the Curing Duration

It’s natural to want to get activities going in your building right after spray foam application, but you need to wait till it cures appropriately before moving in. Depending on the chemical formula used, it takes five to 60 minutes to get a tack-free foam.

Most foam work dries between eight to 24 hrs. after application. This is often affected by the following factors:

1.       Formula used

Spray foam is made of chemicals that react to each other fast, creating a foam insulator component. One of the system’s sides contains methylene diphenyl diisocyanate and polymeric methylene diphenyl diisocyanate.

The other side contains a blend of blowing agents, polyols, flame retardants, surfactants, and catalysts. The two compartments’ contents mix when sprayed to create the foam.

Spray foam has two different types; the open-cell and the closed-cell spray foam. The former is less dense and dries faster. The latter is much thicker, but it also offers air sealing, worth its longer curing time.

To know how much foam you will use for a particular space, multiply the foam’s thickness by the area’s square feet. A 2 ½” thick foam formula will work well for a thousand ft2 area. This gives you about 2500 bf of the foam required for sufficient work.

The formula translates to a dry time of about eight hours or more, though other factors still contribute to the time.

2.       Temperature

For the best work and a faster drying time, spray your foam within moderate temperatures. The temperature should be between 60 to 90 degrees F, which is 16 to 32 degrees C.

Low temperatures make the application surface absorb heat from the foam. This will reduce its effect on the surface and reduce the foam’s kit yield.

For better results, if the temperatures are low, heat the room for an hour before application. Do the opposite for extremely high temperatures.

A test patch helps you know if the temperature is right for the process. If the foam adheres appropriately, you are good to go. Alternatively, apply a thin layer to bring up the ambient temperature. This layer has to be very thin, knowing you are only creating a better application condition.

Once the first layer cures, repeat the application to build up its thickness.

3.       Humidity

The more humid your application space, the longer the foam takes to cure. According to the Air Conditioning Contractors America, a recommended humid condition is at 75 degrees F, which has 50% relative humidity.

A low temperature of about 55 degrees F causes high humidity effects. This is a challenging condition for foam application.

If you do not have many options for increasing your room’s temperature, a dehumidifier might make the place much better. The system heats the air to reduce humidity, which consequently improves the temperature for foam application.

4.       Amount of foam sprayed

Quantity affects spray foam dry time since air and heat have to penetrate through its texture to dry. Therefore, the thicker the foam layer, the longer it takes to dry.

Proper foam installation should cover at least three to three quarter inches lifts. You can apply layers as thick as four inches for better yield, but you also have to be patient with the curing time.

A thin foam layer application is fast and covers a broader space with relatively the same foam amount. However, it has less yield and less cover density.

The energy code requirement of foam application is between R-13 and R-19. This is reachable with a three-inch application layer.

Steps to Ensure Proper Installation

So many horrifying stories have made people shy away from using spray foam insulation. While it is understandable for one to take extra care, you only need to follow a proper application process to avoid unwanted outcomes.

1.       Work with an experienced installer

Due to the complexity of the chemicals involved, spray foam application should not be a DIY endeavor unless you have prior experience. It’s more proper to hire experienced personnel who understands the nitty-gritty of the process.

It will save you reapplication costs and also ensures you follow the authorized application implications in your state.

2.       Choose your products right

Spray foam involves a combination of several chemicals that work together to produce the insulation foam. Given that different manufacturers have various quality levels, ensure you only use proper chemicals from authorized manufacturers.

3.       Prepare adequately

Preparation is as necessary as the application process; therefore, do it efficiently. Cover doors, windows, and any other surfaces you do not wish to come into contact with the foam.

You might need to do away with older foam, if any, and clear the room of any obstructions. Finally, suit up and ensure that no one who isn’t on the job is around during application.

4.       Keep the spray foam on ratio

Both sides of the spray compartments have different chemicals that merge on spraying to create the insulation required. To avoid air quality issues, ensure the ratios are as per the recommended standards.

5.       Spray under ideal conditions

Several factors affect how efficient the application will be. Ensure that the temperatures and humidity conditions are right. Heat the space if need be and use a dehumidifier as well.

6.       Quality test before application

Finally, test the foam before application. You can do this by spraying a bit on a small portion of the surface and see how it adheres. If the formula and other conditions are right, adhering will be okay. Curing should be good after 24 hours.


A lot goes into the preparation, application, and curing process. By following the above steps and considering each tip, an excellent outcome is inevitable.