How Does Spray Foam Compare With Traditional Insulation? Five Quick Facts
“Should we use spray foam insulation, or traditional fiberglass insulation?”
With the rising popularity of spray foam insulation, this question comes up more and more.
There are some clear contrasts between these two types of insulation. Depending on your priorities, you may find that one is a better fit for your project. Let’s look at the biggest differences:
- Spray foam consistently outperforms fiberglass when it comes to energy efficiency.
The biggest downfall of fiberglass insulation is that its Long-Term Thermal Resistance (LTTR) rating is substantially reduced over time. The numbers on a bag of fiberglass insulation (the R-value) are often deceiving. When the bag says R20 it means that it will provide that rating when installed perfectly, without any air movement or gaps. The LTTR of an R20 fiberglass batt is, at best, R12. This is because it will sag and gap for a variety of reasons (gravity, install defects, wires pulled through wall space, vibrations in the house, and so on). For every 1/8" gap you will lose 40-50% of the R-value. Spray foam insulation is guaranteed to never gap, sag, or crack, while fiberglass insulation provides no such guarantee.
- Spray foam increases a building's racking and structural strength.
Many building walls are built to just the minimum standard. They're safe, but still prone to shakes and creaks during storms and internal movement. Apply spray foam insulation inside the walls and it will fill in every crevice between your framing and sheathing, hardening to create another layer of "structure" that supports the walls and decreases movement from wind and interior activity. According to the National Association of Home Builders (NAHB), walls filled with spray foam can triple the racking strength of the building.
- Spray foam can be used for non-thermal applications.
When there are gaps and cracks around doors and windows and in between walls, noise travels easily. Using spray foam to fill those gaps significantly decreases noise levels to create a more comfortable interior atmosphere. Overall, buildings with lots of little "holes" allow moisture in and tend to hold humidity, which ultimately breeds mold and can cause serious health problems for the inhabitants. Moisture can also cause extensive damage to a structure over the long term. In many cases, spray foam simply makes good sense for its multiple purposes and benefits.
- Spray foam is versatile.
Since spray foam expands and adheres to almost any surface, it fills areas that traditional fiberglass can’t reach. Foam insulation assumes the shape of the space where you apply it (curved, round, etc.) while fiberglass retains its own shape, compromising the integrity of the product.
- Spray foam has benefits for metal buildings.
The strengths of spray foam insulation perfectly complement the weaknesses of metal buildings. Metal can promote condensation, but spray foam provides an airtight “thermal break,” eliminating that possibility. It’s difficult to create an air barrier system in a metal building, but spray foam gets the job done by filling cracks and crevices. If your project involves a metal building, you should seriously consider spray foam insulation over traditional fiberglass.
Spray foam insulation clearly has a lot going for it. As the Insulation Specialists, we can help you figure out what type of insulation is best for your project.