Spray Foam Custom Insulation FAQS:
I am confused about the difference between open-cell and closed-cell spray foam insulation. How do I choose between the two?
We get this question a lot. The short answer is that open-cell spray foam is less expensive and, while superior to cellulose or fiberglass in insulating power, air infiltration and moisture blocking, and promotion of healthy indoor air quality, open-cell spray foam has less insulating power per inch than closed-cell spray foam and doesn’t add structural strength to walls and roofs.
Closed-cell spray foam insulation has all the benefits of open-cell spray foam, with almost twice as much insulating power per inch. Plus, the density and sticky closed-cell quality of closed-cell spray foam can add significant strength to frame walls and roof structures. Which should you choose? It depends upon a variety of factors including your budget, geographic location, your energy saving goals and other factors.
You can make the most informed decision by scheduling a visit with Travis. While, as a practical matter, most of our work in existing homes is limited to new attic insulation, the agenda for a site visit can include the following tasks:
- survey your home’s construction, existing insulation, and the accessibility of your attic and walls;
- measure roof and exterior wall surface areas;
- explain different spray foam insulation types and product options;
- provide you with a firm quote for the installation of spray foam insulation in your home.
I’ve seen ads for spray foam insulation kits on the Internet. Is there any reason why I can’t apply spray foam insulation myself?
We do not recommend it. Applying spray foam insulation requires complex equipment, including a plural component proportioner pump with heaters, dual high pressure heated hoses, a high-pressure mixing spray gun, feed hoses, an air compressor, and safety equipment. While spray foam insulation is completely safe once it hardens, the raw ingredient chemicals can be harmful if inhaled or in contact with the skin. Inexperienced installers also have a tendency to underestimate the foam’s expansion, so they waste ingredients by over spraying.
It takes training and experience to apply spray foam insulation with the consistency and quality control necessary to achieve designed performance. Problems can arise if the foam chemicals are mixed in the wrong ratio or at the wrong temperature, causing the cured foam to crack and shrink away from rafters or studs. And working too fast can leave voids in the finished foam, reducing its insulation value. We say leave it to the experts… us! Together we have close to two decades of experience with spray foam.
Does spray foam insulation absorb or trap moisture?
Closed-cell spray foam insulation does not absorb moisture. Period. Open-cell spray foam insulation absorbs moisture but then dissipates the moisture within a relatively short period of time. This is unlike cellulose or fiberglass, which are porous and will allow moisture to pass right through the insulation, soaking the insulation and ruining its insulating power in the process.
Most moisture problems in houses result from air infiltration through walls and ceilings. Spray foam insulation expands to fill even the smallest cracks and openings in walls and roof sheathings, so these moisture sources are virtually eliminated. Proper construction materials and techniques usually prevent moisture buildup from other sources. Contact us if you have questions about an application with unique moisture characteristics, such as an indoor swimming pool room or a walk-in freezer.
I have heard that a roof leak could rot my roof if I have to spray foam insulation on the underside of the roof deck. Is this true?
No, this is not true. Some fiber insulation companies have created illustrations that show water from a roof leak draining down the underside of the roof deck in a spray foam insulated attic. Their suggestion is that water from a leak will become trapped in a space between the roof deck and the spray foam insulation, leading to eventual roof rot.
However, this scenario is not possible because spray foam insulation forms a direct chemical bond with the roof trusses and the underside of the roof sheathing. There is no gap between the roof sheathing and the spray foam insulation, so there is nowhere for the water to go. In fact, spray foam insulation on the underside of your roof deck actually protects your ceiling and valuables by preventing water from leaking through your roof sheathing.
Will spray foam insulation on the underside of my roof sheathing void my roof warranty?
No, this is another myth. The suggestion here is that your roof sheathing and shingles will not last as long because the spray foam insulation increases the roof surface temperature, by preventing heat from radiating into the attic. While your roof surface temperature may be a bit higher, research shows that the temperature increase is only two to three degrees. For a Texas roof surface that can reach 160 degrees or more during the summer, this is a difference of less than two percent. By comparison, the roof temperature increase just from installing dark-colored roof shingles is three times greater.
Can spray foam insulation be applied directly to electrical wiring? What about installed electrical devices like recessed lights?
Yes. Spray foam insulation can be applied directly to electrical wiring. Properly sized wiring should not experience temperature issues. Recessed lights or other fixtures may require a certain amount of air circulation around them for cooling purposes. For fixtures, consider building a box around the fixture with gypsum wall board (drywall). The spray foam insulation can be applied to the outside of the box.
Incidentally, cellulose insulation is recycled paper and should not be placed in close proximity to recessed lighting fixtures. Even though cellulose insulation is treated with fire-retardant chemicals, tests show these chemicals tend to lose their effectiveness over time.