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Is Spray Foam Insulation Good for Your Subfloor? 

Spray foam insulation has been commonly used for maintaining energy efficiency in various parts of the home. But is it beneficial for your subfloor? 

On this page, we’ll explore what the subfloor is, and whether using spray foam insulation is a good idea.  

What is the Subfloor? 

The subfloor is a crucial structural component of a building’s flooring system, or the ‘ceiling’ of your crawl space. It is the layer of material that sits directly on top of the floor joists and serves as the base for the finished flooring material. 

The subfloor provides a flat, stable surface for the finished flooring to be installed on and helps distribute the weight of furniture, occupants, and other loads evenly across the floor joists. 

Subfloor materials can vary depending on the construction method and building codes, but common materials include plywood, oriented strand board (OSB), and sometimes concrete in certain types of construction. The thickness and type of subfloor material used depend on factors such as the building design, expected loads, and local building codes. 

What is Spray Foam Insulation? 

Spray foam is a type of insulation material commonly used in construction to seal gaps, cracks, and voids in buildings. It is a two-component mixture composed of isocyanate and polyol resin, which are combined at the application site using specialized equipment. 

When these two components are mixed, a chemical reaction occurs, causing the mixture to expand rapidly and form a foam-like substance. This expanding foam adheres tightly to surfaces, filling gaps and creating an air barrier. 

Is Spray Foam Insulation Good for the Subfloor? 

While spray foam insulation was a common option in the past, we do not recommend putting it or anything else on your subfloor. These are some of the reasons why spray foam insulation is not recommended: 

  • Moisture Concerns: Spray foam insulation traps moisture. Both open cell and closed cell foam seal moisture, making it so that wood can never fully dry. 
  • Mold Growth: Spray foam insulation is prone to grow mold. Mold has a constant food source due to the moisture in the wood. 
  • Removal Difficulty: Should the need ever arise, spray foam insulation is very difficult to remove from the subfloor, leading to costly removal solutions down the road. 

Putting spray foam insulation on your subfloor is not recommended. In fact, it’s best to not put anything on the subfloor because it could inhibit airflow from the crawl space to the home. It’s essential to consult with encapsulation professionals like those at Tar Heel Basement Systems to determine the best insulation options for your specific needs and circumstances. 

What We Recommend  

At Tar Heel, we offer foam board insulation, which heat-reflective surfaces and excellent insulation value, despite being thinner than other types of insulation. It has numerous benefits, including:  

By installing foam board insulation on the crawl space walls, air can flow upward into the home and help maintain the warmth of your floors. Our crawl space encapsulation solutions and services guarantee optimal results. 

Contact Tar Heel Basement Systems Today 

Trust Tar Heel for your crawl space repair and encapsulation needs. Whether you are dealing with rising energy bills or crawl space moisture, we offer solutions tailored for your specific needs. During an inspection, our professional team will assess the issue and determine the next steps, guiding you every step of the way.  

Schedule a free inspection today.  

Phillip Mazzotta

Phillip Mazzotta

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