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Spray Foam Is Not a “Silver Bullet”

Updated: Sep 29, 2023

Spray foam is one of the most popular insulation options and some people believe it may even be a silver bullet for making homes comfortable and efficient. However, while spray foam insulation has many great features, it isn’t ideal for all scenarios, and it’s important to understand that the experience of the person or company installing the foam is just as important, if not more so, than the product itself. Also important is knowing what other insulation types are out there.

Insulation Types

In order to gain a deeper understanding of which insulation type is right for you, it’s crucial to know which popular insulation options exist and where they provide the most benefit.

Cellulose Insulation

Made out of recycled newspaper, cellulose is one of the most environmentally-friendly options available. It has a higher effective “R-value” than fiberglass, and it is fire, mold, and pest-resistant. Cellulose is often used in attics, floors and walls.

Denim, Cork and Wool Insulation

These insulation options are available for homeowners particularly concerned with their impact on the environment. While denim, cork and wool insulation don’t have an extremely high R-value per inch (or thermal resistance), they are a great solution for homes with certain eco-friendly requirements, although they are typically more expensive and difficult to locate in some areas.

Rigid Foam Board Insulation

A high R-value, sturdy insulation option, rigid foam board is often used in crawlspaces, dormers, knee walls (attic-facing walls), on exterior walls, and on a home’s foundation walls.

Fiberglass Insulation

Used most often due to its low cost, fiberglass is the most commonly used insulation across the US. Many homeowners also attempt to install fiberglass, particularly fiberglass batts, on their own. However, both fiberglass batts and blown-in fiberglass should be installed carefully by a professional to ensure they fill cavities properly and aren’t compressed, which is often very difficult to do. Again here, the expertise of the person installing the product is crucial to getting the material to perform as intended.

Spray Foam Insulation

Spray polyurethane foam exists in two varieties: high-density and low-density. High-density “closed-cell” spray foam insulation is very durable and effective at sealing leaks, which helps to reduce energy loss and moisture issues. It is also considered a “vapor barrier”, so it’s often used in below-grade applications, like foundation walls for basements and crawlspaces. Low-density “open-cell” spray foam is a less expensive option that isn’t as durable as closed cell, and it also isn’t considered a vapor barrier either. Open-cell also has about half of the R-value per inch of thickness applied versus closed-cell foam, so you need twice as much to get the same R-value. However, both spray foam options provide a combination of insulation and air sealing benefits which can be very effective when installed properly and in the right locations.

Damaged spray foam after installation
Damaged spray foam after installation

Why Spray Foam Insulation Isn’t a Silver Bullet

While spray foam is a useful insulation product, it isn’t right in every case, and unfortunately many problems exist with the installation of spray foam that can reduce its effectiveness significantly. As the demand for spray foam insulation has grown, more contractors have begun installing this two-part chemical product, and unfortunately not all installers are properly trained to do it well. Without proper training, installation techniques, and quality control, spray foam applications can quickly become ineffective and even dangerous to the home’s health.

Open cell spray foam can sometimes fold over on itself, which leaves unfilled gaps. Often, spray foam is applied too thinly, reducing its R-value and air-sealing abilities. Issues with mixing the two-part chemical can also reduce its ability to stick to framing and concrete, while sometimes cured spray foam contracts and pulls away from the surface, leaving large areas uninsulated. This can also happen if the temperature of the foam mixture isn’t just right, or if the surface it’s being applied to is too cold. The thickness of the foam, incomplete coverage and foam contraction are problems often seen with spray foam insulation.

Since spray foam insulation is extremely effective at air-sealing and insulating, if a home is not ventilated properly and an attic or crawlspace is sealed and insulated with spray foam, humidity can quickly build up, causing problems with mildew or mold. When using spray foam, it is crucial to ventilate properly during the actual installation, as well as afterwards to ensure you don’t trap any off-gassing chemicals or moisture inside your home. If not done, this can create significant indoor air quality and respiratory issues!

Improperly installed spray foam insulation
Improperly installed spray foam insulation

Building Performance Makes Sure Your Insulation Is Installed Right!

Our RESNET-certified inspectors have decades of experience with all kinds of homes and buildings in Indiana and Kentucky. We can inspect your new or older home and determine which types of insulation are best for your needs. We also offer HERS Ratings for new homes (home energy ratings), which includes energy code compliance verification services, such as blower-door testing and duct-leakage testing. We will work to help you achieve the most comfortable, healthy, and energy-efficient home you can afford!

Contact us or call (502) 509-5535 today to learn more about insulation options and to schedule an inspection!

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