What is spray foam insulation?
Also known as spray polyurethane foam, spray foam insulation is a type of plastic insulation composed of isocyanates and a polyol resin blend. These chemicals are mixed together and applied using a spray gun system, at which point the mixture rapidly expands to up to 30 to 100 times its liquid volume. Within seconds, the spray hardens and bonds to the application surface, creating an effective barrier and adding structural strength.
Because it significantly expands as it's applied, spray foam is particularly useful for penetrating and filling cracks, holes and other openings near the application site. This virtually eliminates air infiltration, enhancing the effectiveness of the insulation when compared to fiber insulation materials. It's available in a variety of densities to suit nearly any application. It also enhances comfort by reducing temperature inconsistencies and minimizing unwanted outdoor noise.
How long has spray foam insulation been around?
The basic technology behind spray foam insulation can be traced back to the work of Otto Bayer in the 1940s, but technological advances in the 1960s made the foam more suitable for insulation in commercial and industrial applications. It was first used for roofing insulation in the 1960s because of its ability to seal out water. However, its insulating efficiency made it more popular during the energy crisis of the 1970s.
Considering its advantages, why is spray foam used less frequently than other insulation types?
Spray foam insulation offers superior performance and energy savings, but there are a few reasons many people still rely on traditional fiber insulation. When it first rose to popularity in the 1970s, early formulations were made with highly toxic formaldehyde. As a result, many people stopped using spray foam products entirely. More modern formulations contain no formaldehyde and are completely safe to use.
Another factor comes down to short-term versus long-term cost. Fiber insulation is less expensive to purchase and install than foam, so the lower short-term cost makes it a more popular option. The problem is that fiber-based products tend to allow significant air infiltration and provide substandard insulation performance. By comparison, foam insulation eliminates most air leaks and delivers outstanding thermal insulation. Considering around 40 percent of heating and cooling costs can be traced to air leaks and poor insulation, the performance of spray foam makes it a far greater long-term value.
Does spray foam insulation meet building code standards?
Yes, but with one important caveat. Foam insulation is approved for use as detailed under the "Foam Plastic" section of the building code. However, unless the foam has been specifically certified as exempt, it must be installed with a thermal barrier to protect against fire.
Does insulation have to be installed by a licensed contractor?
No, hiring a licensed contractor is not legally required, but it's the best way to ensure optimal results. Insulation that isn't properly installed is often less efficient and more prone to air and water intrusion. At best, this means you won't save as much as you might expect on energy costs. At worst, it could lead to poor air quality, fungal growth and even water damage. State-licensed contractors, such as Sensigreen Mechanical must meet strict standards and demonstrate a high level of knowledge and expertise, ensuring your insulation will be installed correctly.
Should I choose open-cell or closed-cell spray foam insulation?
Spray foam insulation comes in two distinct varieties, each of which offers its own advantages and disadvantages. Closed-cell insulation is the best choice for the highest level of insulating and moisture-blocking performance. It has nearly twice the insulating value of open-cell and can often be layered over multiple applications for even better results. Depending on the product, closed-cell can also act as a structural reinforcement, vapor barrier and E84 flame retardant.
Open-cell spray foam is considerably more affordable, making it a good choice for tighter budgets. It also achieves greater expansion, which can be useful for insulating spaces that are otherwise difficult to reach. It falls short of closed-cell insulation in terms of performance, but it still far exceeds fiber insulation.
Ultimately, whether open-cell or closed-cell foam is right for you depends on a number of considerations. The best course of action is to consult with an experienced installer. A Sensigreen Mechanical professional can guide you through several steps to help you make the optimal decision for your home and budget, including:
- Evaluate your home and its insulation needs
- Compare and contrast spray foam insulation options
- Review available financial incentives
- Identify insurance discounts and other savings opportunities
- Offer a comprehensive quote for the solution you choose
Is installing spray foam insulation cost-effective?
Despite the higher initial cost compared to fiber-based insulation, spray foam insulation is a smart and cost-effective investment. First and foremost, the superior insulation performance of spray foam means you'll save money on heating and cooling costs each month. In fact, although the exact degree of savings depends on a variety of factors, foam insulation reduces energy consumption in the average home by around 20 to 40 percent each month compared to traditional insulation materials. This adds up to a significant return on your investment that will continue paying off for years.
Additionally, spray foam insulation can help to reduce the cost of new construction as well. More efficient insulation may allow you to install a smaller and more affordable HVAC system without losing heating and cooling performance. Because it does the same job even more effectively, spray foam can also eliminate the need for installing house wrap.
Can I simply buy a kit to install spray foam insulation myself?
Yes and no. It's possible to purchase kits that allow you to apply spray foam insulation, but installing it properly is an entirely different matter. Proper installation requires a degree of precision, consistency and control that's difficult to achieve without professional training and an experienced hand. The component chemicals must be mixed at precisely the right ratios and temperatures to ensure proper curing and adherence. The foam must also be applied evenly and consistently to prevent material waste, air cavities and variations in insulation values.
More concerning still is the danger of working with hazardous materials without the proper equipment and training. When it's correctly mixed and hardened, spray foam insulation is rendered inert and entirely safe. However, the individual component chemicals can be hazardous, and they may remain potentially harmful if they aren't mixed correctly. For these reasons, spray foam insulation should only be installed by experienced, properly equipped professionals.
Does foam insulation pose any safety concerns?
Not if it's installed by a professional. The earliest spray foam products used toxic formaldehyde, but modern foam insulation is completely safe once it hardens. It's rendered fully inert after application and does not release any hazardous emissions.
What is the typical lifespan of spray foam insulation?
One of the best things about spray foam insulation is that it's incredibly stable. Once the foam has been applied and allowed to cure, the result is insulation that's chemically inert, physically durable and not susceptible to water damage. Some spray foam installations have been around for over 40 years now, but that may be less than half of the expected lifespan. However, long-lasting performance is only possible with a quality installation.
Is spray foam insulation impervious to moisture?
That depends on the type of insulation being used. Closed-cell foam insulation is effectively impervious to moisture and can act as a vapor barrier. By contrast, open-cell foam is somewhat permeable, but it dissipates moisture quickly. This prevents many of the moisture-related issues associated with highly porous insulating materials like fiberglass and cellulose.
Another benefit of spray foam insulation is that it actively eliminates moisture at its most common sources. Water most often enters the home through air leaks in walls and ceilings. During application, spray foam rapidly expands to seal up any leaks and create a virtually airtight barrier. Moisture sources originating inside the home can be resolved by ensuring proper construction. For applications in which moisture poses a challenge, we'll be happy to work with you to address any concerns.
Could spray foam insulation put my roof at risk in the event of a leak?
One of the most common concerns surrounding spray foam insulation is roof rot. The idea is that a leaking roof can cause water to become trapped between the roof deck and the moisture barrier formed by the insulation. This, in turn, leads to rotting of the roof's structural components. This misconception has been encouraged by fiber insulation companies, but it simply doesn't match reality.
In fact, spray foam insulation acts as a safeguard in the event of a leak. During the application process, the spray foam material chemically bonds with the roof trusses and sheathing. This prevents water from penetrating through the roof sheathing and leaves no space in which water can even become trapped.
Will my roof's warranty be voided if I apply spray foam insulation under the sheathing?
No. When it comes to the longevity of shingles and roof sheathing, heat is one of the greatest enemies. One of the ways a roof deals with excessive heat is by radiating some of it into the attic. In theory, installing foam insulation under the sheathing could disrupt heat transfer and increase the roof's surface temperature, causing excessive wear. In practice, testing has shown only a very minimal increase in surface temperature. Your roof, and the warranty that protects it, will not be affected by spray foam insulation.
Can spray foam insulation be safely used in proximity to wiring and electrical devices?
With the exception of obsolete knob-and-tube wiring, it's completely safe to apply spray foam directly to electrical wiring. However, certain recessed lights and other fixtures need some air space to achieve effective cooling. In these cases, it's often best to build a drywall box around the fixture and insulate the box from the outside. While spray foam is generally safe, cellulose insulation should never be installed near lighting fixtures. The fire retardant treatment applied to cellulose fibers is known to gradually become less effective, making it a potential hazard.
Can an electrical outlet be added or moved after spray foam has been applied?
Yes. Although the electrical rough-in is typically completed before applying spray foam insulation, an electrician can pull wire through the insulation if necessary. For applications in which you may need access to the wiring in the future, installing an ENT raceway can make the task easier.
Can drywall sheathing still be easily installed once spray foam insulation has been applied between framing studs?
Yes. Because it expands significantly on contact, you may see bulges of insulation extending well beyond the wall frames shortly after application. However, this is only temporary. Once the foam has sufficiently hardened, any excess insulation is removed with a scraping tool or hand saw. The end result is a smooth, flush surface that's ready for problem-free drywall installation.