There is a lot of mystery surrounding spray foam insulation. Its one of those topics where if you ask 3 people you get 10 answers. How do you know who to believe when you are looking for answers on your next insulation project? Here we will address some of the common myths about spray foam insulation. We are calling them myths because the facts are different. Opinions can be hard to change but if we look at each topic objectively, and the science behind it, we can draw some factual conclusions.
Myth 1: Spray foam is toxic and dangerous to install in your home.
Most of us have seen a spray foam contractor wearing a respirator and tyvek suit who looks like something out of a movie. It can be easy to draw a conclusion here that the final product must be toxic in some way. Its important here to understand that we have to look at 2 separate things. One is the raw chemicals that the contractor combines to manufacture spray foam. The second is the final finished product that you live with long after the contractor is gone.
The chemicals: Spray foam insulation is manufactured on site at your home or business. Two chemicals stored in drums get heated, pressurized, and pumped through long lengths of hose to the area to be insulated. Its only at the very tip of the spray gun, when the trigger is pulled, that these chemicals mix and begin reacting to form the finished foam. These chemicals are called an “A” and a “B”. The A being Isocyanate and the B being a polyol or resin. The precautions required when handling or spraying these products can be found in the safety data sheet which accompanies the product. These handling instructions are required for all chemicals. In the case of spray foam application, it is important for proper protective equipment to be used by the applicator since spraying at high pressure exposes them to vapors, aerosols, and particulates of these chemicals. Most people can easily understand that we all want to avoid breathing in any amount of chemicals in the air. Proper PPE along with engineering controls like large intake and exhaust fans in the workspace mitigates these risks for the contractor, and allow for a safe installation. So how does this translate to the finished product?
The finished foam: Many products are like spray foam in terms of requiring protective measures during installation but being completely safe when finished. Even something as common as spray paint requires certain measures to be taken to reduce the risk of inhalation or exposure. Its right on the back of the can. At the same time, dried paint is completely safe and there isn’t a risk to people. Finished foam is completely inert. This is well documented and millions of people have been enjoying the benefits of spray foam insulation without issue.
Myth 2: Spray Foam will leave a smell
As they say it only takes a few bad apples to spoil the bunch. They also say that a happy customer may tell a few friends, but an angry customer wants to tell the whole world. There absolutely have been faulty spray foam insulation jobs. Unfortunately the bad jobs and the bad contractors are the ones you hear about and this keeps this myth alive. As we said previously spray foam is completely inert, so how could someone end up with a lingering bad smell after the job was done? Simply put, a bad smell was caused by a bad job. You probably wouldn’t want someone who started last week to paint your nice car, and you probably shouldn’t let someone without experience and training spray foam your home. That is because the most important thing for a successful job is the ratio of the foam and the thickness per pass. Spray Foam is mixed at a 1 to 1 ratio of the two chemicals. Too much or too little of one or the other will cause a number of issues. Its like following a recipe. If you just inserted any amount of any ingredient you never know what you will end up with. Many things could cause an off ratio condition when spraying foam but a trained and experienced applicator can see it and stop to make corrections instantly. A less experienced contractor may not realize or not care and continue installing a bad mix of foam which is ultimately what leads to more stories of bad jobs and unhappy customers.
The second part of this is about thickness of foam per pass. What does this mean and why is it important? Sprayed polyurethane foam is installed in layers to get to a final depth. Foam is formed via an exothermic (heat-releasing) chemical reaction. This heat and any gasses need to be released before more foam is added on top. Most manufacturers specify about 2 inches maximum per pass to allow this to take place. If a lazy or just untrained applicator decided on a Friday afternoon to install 8 inches in one pass, well, bad things will happen. The heat and gasses are trapped and in the worst instances this bad foam continued to give off gas and cause trouble for homeowners. Every day spray foam is installed all over the country without any lingering odors. Unfortunately the customer who was stuck with a bad job that did cause a lingering odor is the story heard most.
Most people don’t consider how much foam is already all around them in their daily life. Your refrigerator is insulated with closed cell foam, your living room couch, the seats in your car, maybe even your bed pillow or mattress are foam. We know that unless something went really wrong during the manufacturing process these aren’t constantly emitting bad smells and the same is the case with foam used for your insulation.
Myth 3: A house needs to breath and foam insulation will make it too tight
The short answer is that people need to breathe and houses need the ability to dry. In the early 1970’s people started experimenting with tighter insulation techniques without taking into account the entire structure. Many moisture issues arose and the old timers pointed out that the old farm house with no insulation never had moisture issues so we should leave homes drafty for longevity. We know this isn’t the case now. Building science has come a long way. There is definitely a middle ground between a house so drafty that it can barely be heated to a comfortable level, and a house so tight that humidity from cooking, showering, and people breathing increases to high levels that cause health concerns or threaten to rot the structure. The popular saying now is build it tight and ventilate right. A house can and should be built as tight as possible, and moisture levels and fresh air should be controlled by the HVAC system. Air exchangers now have the ability to ventilate the home with a precisely controlled amount of fresh air, even the ability to retain heating and cooling. These are called energy recovery ventilators (ERV) or heat recovery ventilators (HRV), Humidity is maintained at the correct level and all air flows through a filter. This means stale moist air can be removed, fresh air can be introduced, all while keeping your energy bill in check.
Myth 4: Spraying foam on a roof deck ruins shingles
The myth that roofers love to push. First, why do they say it? They are saying that shingle temperature would be too high if they cant breathe into the inside of the attic space. So you are left in the middle. Your HVAC unit is in the hot attic and you are exploring insulating the space to save on energy costs. Your roofer claims it would void the shingle warranty. So what do the actual shingle manufacturers say? Two of the biggest shingle manufacturers in the US, GAF and Certainteed have bulletins stating that spray foam insulation does not void their shingle warranty when installed correctly. The Florida Solar Energy Center did a comprehensive study on shingle temperature of vented vs unvented attics and found a minimal difference in temperature. They found that shingle color has a much more significant impact on shingle temperature than whether there is or isn’t insulation underneath. If shingle temperature is a major concern for the roofers who push this narrative, they should probably suggest white shingles.
Myth 5: Spray foam insulation is not worth the cost compared to fiberglass or cellulose
Sure, fiberglass costs almost nothing. Does that make it the best choice? Is up front cost the main factor when choosing an insulation product? What is the true cost? Since the department of energy states that up to 40% of energy loss is due to air leakage in a home, is a fiberglass batt with no ability to stop air going to result in an energy efficient home? How much will it actually cost in the long run? You could ask your builder to pay great attention to sealing every crack and gap before installing fiberglass, rock wool, or cellulose and how would they do that? Most likely by using cans of foam. In fact even people who think that spray foam is not worth the cost probably have used foam from a can due to how good it is at sealing every gap. So if one product stops all air leakage, and the next does not, the true cost over the long run is not just the up front installation cost but the difference in energy bill for the time you plan to live in the home. Every house is different but even a modest difference in monthly energy bill is like a dividend on investment. We have customers routinely telling us they are saving 30-40% or more with spray foamed houses.
If you have further questions about spray foam insulation, the team here at Amira contracting would be more than happy to answer them. We can be reached through the contact form or by email [email protected]. You can also call us anytime at 302-464-0644.