Can Spray Foam Be Applied Over Existing Insulation?

If your home already has insulation but still feels drafty or uncomfortable, you might be wondering—can spray foam insulation be applied over what’s already there? The answer is sometimes, yes—but it depends on the condition and type of your existing insulation.

Here’s what you should know before adding spray foam on top of older materials:

1. Check the Condition of Your Current Insulation

If your existing insulation is wet, moldy, or damaged, it should be removed before applying spray foam. Moisture and decay can prevent proper adhesion and lead to air leaks or trapped mold later on.

2. Compatibility Matters

Spray foam can be applied over certain types of insulation—like fiberglass batts or cellulose—as long as the materials are dry, clean, and stable. However, if the old insulation is loose or deteriorating, it’s best to remove it to ensure an airtight seal.

3. Air Sealing and Efficiency

One of the biggest benefits of spray foam is its ability to seal gaps and air leaks, something traditional insulation can’t do. Applying spray foam properly ensures improved energy efficiency, lower heating and cooling costs, and a more comfortable home year-round.

4. Trust Professional Installation

Applying spray foam over existing insulation requires the right tools, safety gear, and expertise. A professional installer can evaluate your current insulation, recommend the best approach, and make sure the foam bonds effectively without causing moisture or ventilation issues.

At Custom Insulation Company, Inc., our team provides expert evaluations and safe, high-quality spray foam applications for homes and businesses. Whether you’re upgrading existing insulation or starting fresh, we’ll help you create a more energy-efficient and comfortable space.

Contact us today to schedule a consultation and find out if spray foam can be applied over your existing insulation.