Many Types of Foam
According to the polyurethane foam association over 1.8 billion pounds of flexible polyurethane foam (FPF) products are produced annually in North America. There are many different types of foam out there; they are all based on altered forms of plastic filled with micro bubbles.
Some examples of FPF products are: polystyrene foam, polyethylene foam, styrofoam, and polyurethane foam. Polystyrene foam (often blue) is used in rafts, life preservers, and insulation wraps for residential homes. Polyethylene foam is used in cushions, pillows, and beds. Styrofoam is usually white, and typical uses are white foam for coolers, mugs, or cups (e.g. coffee/ or hot chocolate). Finally, polyurethane foam is a yellow type of foam for roofing, insulation, refrigeration warehouses, foam boards. Foam roofing is one of the most common polyurethane foam applications.
Foam Roofing Myths
There are probably as many myths as there are types of foam. Some of these misconceptions may be partly due to the fact that there are so many different kinds of foam. With about three decades of foam roofing experience we have heard some myths so absurd we wont bother listing them here. This article is an attempt to dispel some of the most typical myths and rumors about foam roofing. Without further adieu, here are ten of the most common polyurethane spray foam roofing myths, listed in no particular order.
Picture: A Sprayed Polyurethane Foam roof (SPF) installation on a warehouse. SPF foam roofing is plagued by myths and misconceptions .
Myth #1: Foam Roofing is New
Although the groundwork for polyurethane foam was done by Otto Bayer and his team in 1937, polyurethane foam would not become available until much later. In 1952 polyisocyanates became commercially and commercial production of polyurethane foam began in 1954 based on toluene diisocyanate (TDI) and polyester polyols. Commercial production of flexible polyurethane foam began in 1954, based on toluene diisocyanate (TDI) and polyester polyols. The invention of these foams (initially called imitation Swiss cheese by the inventors) was thanks to water accidentally introduced in the reaction mix. These materials were also used to produce rigid foams, gum rubber, and elastomers.
Dr. Otto Bayer began working with polyurethanes in 1937. However, it was not until further innovations, and Walter Baughman’s discovery of the Blendometer in 1953 that mass production of polyurethane foam began. As a product, polyurethane foam is over half a century old.
Initially polyurethane spray foam was used in the 1960s for refrigeration and industrial insulation projects, although by the late 60s and early 70s polyurethane foam had evolved into exterior roofing applications. The earliest foam roofs are now around 50 years old. So, as a product, polyurethane foam has existed for the better part of a century, and it has been in use on roofing in applications for about half a century. For most of the living world, foam roofing is indeed not new.
Myth #2: You Can’t Stop a Determined Bird From Pecking a Foam Roof
This is very much a myth, and if you believe it, you should be ashamed. Now, keep in mind that If you have a sadly deteriorating foam roof, with large patches of exposed foam (where the acrylic coating has worn away), then birds may peck at your deteriorating and exposed foam.
One popular foam roofing myth involves birds pecking a foam roof into oblivion.
However, it’s very easy to stop the birds from doing this (i.e. the “can’t stop” part is a myth). Simply replace the coating with a fresh layer or use some acrylic caulking to seal up the exposed area. When an added layer of rubberized coating covers the foam, surface toughness increases such that birds tend to stop pecking as they find that their beaks bounce-off the roof surface. Keep in mind that this type of work is best performed by qualified technicians who understand surface preparation procedures and have access to suitable materials. If you do find a bird pecking at your foam roof, think of it as a compliment. Even a bird’s brain is smart enough to realize that foam is both lightweight and has great insulating qualities (e.g. for a nest).
Myth #3: You Can’t Walk on a Foam Roof
You CAN walk on a foam roof without having the skills of those ninjas that walk on rice paper; just leave your spiked heels and cowboy boots in the closet–its best to use soft rubber sole sneakers. Unless you’re walking on a condemned (or soon to be) building, a foam roof is completely capable of sustaining the weight of a normal person.
Employees walk on an SPF foam roof while making an inspection.
Soft sole shoes are advised because an extremely sharp object can damage or penetrate the foam. Since spray foam roofing structure is composed of millions of tiny closed cells, only a hole in the roof that penetrates to the underlying substrate can potentially cause a leak. However, foam can only last forever if it is protected from UV rays (sunlight). If your foam roof has a hole or is damaged, a proper type of coating or caulking should be used to coat the roof again and protect it from UV rays.
Myth #4: Foam Roofing Material is Just Like Memory Foam Mattress Material
Sure, and monopoly money is accepted by your local bank. On a more serious note, memory foam mattresses are very low density and open cell, while foam roofing foam is still flexible, it is relatively much higher density and composed of closed cells. Polyurethane closed cell foam used in roofing applications is a completely different material composition vs memory foam. Polyurethane foam used for roofing applications is exponentially stronger and more durable than the type of foam used in a mattress. For example, Dura-Foam has many roofs approaching the 35 year mark which are still in near perfect condition.
Myth #5: Foam Roofing is Expensive
A foam roof actually costs about the same as a typical BUR or single ply roof. Also, consider that BUR or Asphalt roofs are actually an oil based product. Rising oil prices are driving up the costs of most typical flat roof alternatives, while the cost of foam roofing has remained more constant. An additional benefit to consider, is that a foam roof is the last roof you’ll ever need to buy. Furthermore, a foam roof provides exceptional insulation, and we always use reflective cool roof coatings (on completed foam projects) which results in even further reduced energy costs. Cool roof coatings alone can cut down cooling costs by 30 percent or more in warmer climes.
If you’re only considering a 5 or 10 year window, a foam roof may or may not be more expensive than a traditional roofing material. However, when you start considering 15, 20 or more years in your evaluation, the foam roof becomes much more cost effective than other alternatives. You wont need to replace the foam roof in 20 years–you can simply maintain a foam roof by periodically adding re-coats to protect the roof from prolonged UV exposure. This is not a viable option with a traditional roofing installation.
Myth #6: Foam Roofing is Not Durable
When you think about ‘tough’ materials, foam products probably don’t come to mind. However, Dura-foam has built many 30 year old (and counting) foam roofs which remain in great condition. Many of the earliest foam roofs are still standing (50 years and counting). Foam roofing has already stood the test of time, and its a fact; a foam roof can last the life of your building.
Image: This is a pair of polyurethane soled shoes. Polyurethane is often used in the soles of shoes due to its extreme durability.
Mtyth #7: Foam Boards Insulate as Well as a Sprayed Foam Roof
Not really–whether you DIY (Do-it-Yourself) or have a contractor install a foam board roof, you’ll only see a fraction of the benefits possible with sprayed foam roofing. Sprayed foam roofing is manufactured on site, and is sprayed to perfectly conform to your roof as a single monolithic barrier to the elements. A foam board roof is full of seams which allow moisture and vapor transmission, which greatly reduces the insulation capacity.
Although the R-value rating of a foam board roof appears to be on par with a foam roof, the actual performance of such roofs is substantially inferior. In other words, in this case, the R-value of the insulation does not factor air-infiltration with thermal resistance which makes it an inaccurate comparison. One should also consider a sprayed foam roof also seals a roof better (prevents leaks) better than any traditional pre-manufactured material (even foam boards).
Myth #8: Polyurethane Foam is Toxic
Here’s just one more myth to add to our list. Polyurethane foam is really just a form of altered plastic with millions of tiny trapped air bubbles. Although the formulation is designed for roofing applications and optimized for the best combination of thermal resistance and durability, the base material is the same thing used in most refrigerators or foam mattresses. Polyurethane foam materials are completely inert, and are just as safe as the foam pillows you probably have on your couch by your TV or in the seat cushions inside your car.
Myth #9: Soy Foam is Substantially ‘Greener’ Than Polyurethane Foam
We have looked at the most recent Soybean oil based foams, and they presently contain a maximum of about 15% soybean oil. Considering the expense, and the risk that these formulations wont stand the test of time (last the life of your building), we are not completely sold on this product.
Perhaps one day, Soybean oil based foams will be substantially different from traditional foam. For now, its 85% exactly the same as your every-day polyurethane foam, and for us, it’s not enough to justify the added expense. Although we will look for new developments in bio-based foams in the future, our present conclusion is that soy (and other bio-based) foams are just a gimmick. Once technology changes and the second generation of soy based (and other bio-based) foams are released, we will re-visit the subject.
Myth #10: Foam Roofing Absorbs Water
If foam on a roof system is found to soak up water, either the wrong material was used or the material components were not applied using the proper equipment and expertise. The Spray Polyurethane Foam (SPF) used in roofing applications is “closed cell”. In other words, it is a plastic with millions of tiny closed cells which are impenetrable by water. A block of SPF submerged under water will remain buoyant and dry indefinitely. For this reason, spray polyurethane foam is used in flotation docks and the hulls of sea vessels. In roofing applications, closed-cell SPF is manufactured at the job site using specialized equipment. Foam that soaks-up water is not classified as “closed cell” SPF.
Summary
During the last few decades foam roofing has grown in popularity and become the flat and low slope roofing material of choice for environmentally conscious consumers. Unfortunately, there are some obstacles for foam roofing contractors due to large amounts of misinformation that have propagated through society. There are many foam roofing myths; the ones we have listed here are just some of the most common ones. Foam roofing is truly a highly quality, high performance product. Hopefully this article will help at least a few people separate fact from fiction in reference to foam roofing.
I didnt realize polyurethane foam has been around for 50 years. That seems like a really long time. I wonder why it hasn’t caught on more than it already has.
Seriously, what bird would want to eat foam? I haven’t heard that one before, it seems a bit ridiculous.
My chickens LOVE foam.
jamie birds use insulation pieces for building their nests.lol
Even a birds brain is smart enough to realize that foam is both lightweight and has great insulating qualities (e.g. for a nest). lol
I own a restaurant if Florida. I had a foam roof applied to my building, which had a 7 year warranty. A couple years later I found about 30 quarter-size holes in the foam. They didn’t go all the way thru the foam – they were about 1/8 inch deep. They looked like where a bubble had formed and the top flaked off. The contractor would not repair the roof under the warranty, claiming that birds had caused they damage. I knew that he was lying and reading your website only confirms my suspicion. It is obvious that the material was not applied correctly or the roof was not properly prepped.
John, based on your description, those sound like they may be small foam bubbles. Bubbles often occur if even a small amount of moisture gets caught between layers of foam during the installation process. Those 30 bubble could have been caused by 30 beads of sweat fallen from the installation crew. Fortunately, bubbles rarely result in a leak. After all, they hold air pressure! Anyway, you can fix them by trimming away the separated material and filling the void with any high quality polyurethane sealant.
I have a 50 y/o Cape Cod. I replaced the slate with shingles 18mths ago. The underdecking was pristine tounge and groove boards. I intend to use closed cell spray on the underdecking.. Will the closed cell foam rot my roof?
Foam is plastic based, mold resistant, water-proof, and vapor trapping. Properly installed foam would never cause anything to ‘rot’. Just be sure to hire a reputable, experienced contractor with a good BBB rating (and few or no complaints); then I’m sure things will work out for you.
I am looking at an old mobile home to buy and it has white foam on the roof. It looks bumpy. What do I need to know about this, and does a foam roof need a coating of something to protect from UV?
I have been told that spray on roofs can not be applied to residential gambrel and gabel roof systems. Is this true? And if so why?
Foam roofing has taken a long time to become popular i feel because the equipment is expensive . You have a major investment in the equipment need. I did a test on birds eating foam .I put a tarp on the ground in my back yard i put 100 chip of foam on it and bird seed my conclusion is the birds ate every bit of bird seed and did not eat one piece of foam.
I am waiting for my contractor to have mine done. I pray it works for me. Finding this process might have been a God send. But I am still scared. I really have little money and really extending myself to do this. I have a 30×40 100 year old flat roof. It has only had tarpaper on it so far. The roof is reall bad. The stucture is not great. I just can not afford to tear it all off and build a new roof or even just new decking. The roof could never handle much more weight. Am I right in thinking this will be good for me and be my seviour?
I am absolutely amazed that the foam roof was created prior to WWII and after the Great Depression. now that is history. We’ve had our foam roof for nearly 10 years, and not one leak, cracks etc, and we live in Phoenix. The roof has out lasted extreme heat 117, to major hail storm, and the latest 5 hour rain storm. A fabulous product.
Oh my neighbor has a shingle roof and she lost 15 tiles and major leaks…
Somewhere i saw an article about emergency housing formed by making a tent-like structure with a frame and tarpaper, and then spraying it with PE Foam that formed both an unsulated roof and prided strength to what is a very basic structure. The reflective tar paper interior provides added insulation ans is largely resistant to catching fire when lamps/lanterns are used internally. There was an option of covering the foam with silvered tar paper externally and although extremely basic accommodation it gave good protection from snow etc in remote areas such as Nepal.
Has anybody else heard of this emergency housing method, and are there any links to related sites. The issue is that the system is so cheap that nobody can make money out of it…
Birds dont eat the foam, they just peck at it. Like a dog chesing on something, a horse chewing bark off of a tree, bears scratching trees, -birds like to peck.
In the Top 10 Foam Roofing Myths section, it mentioned to maintain a foam roof we may need to periodically adding re-coats to protect the roof from prolonged UV exposure. Does anyone know if this recoating work must be done by the professionals or it is a DIY work.
We’ve always just painted the foam roof ourselves. Simple to do and does not require anything difficult. We do this about every 5 or 6 years. But use the correct paint! Silicone, UV protection. It is a DIY project.
It’s possible as a DIY as long as all the right methods and materials are used and give a BIG HIGH FIVE to those who do it successfully! I’ve seen a number of DIY roofs develop adhesion issues where vital steps were missed or performed incorrectly.
It has to be done by the same company with a charge, about 25% of the original.
I think this article is very helpful for us,it has solved our problem,thanks!
Could this be used on a typical high pitched residential roof, like my house?
Yes, foam roofing will work on pitched roofs as long as they are not too steep. The foam technician needs to be able to walk across the roof surface while spraying a smooth pattern. At pitches steeper than 4″/12″, walking freely without slipping and smooth foam application tends to become too difficult form most foam technicians.
Great post. Blog is informative for the consumer’s point of view, they have more options for the roofing and their roofing contractor.
Had a contractor talk me into applying elastomeric over my hot tar roof he said someday I can have the roof foamed, True?
Yes, spray foam can be applied over the elastomeric coating. The foam contractor should thoroughly scrub the existing asphalt/elastomeric surface to assure any loose elastomeric material is removed prior to foam roof installation.
All the myths are valuable. For repairing there is only one myth what works. Leaks could also be through with a repair of easy steps one is review for leaks and second is cure them with RV Roof Repair.
I live in Texas with a 2level high-pitched roof and need a second new roof to replace the one we just got two years ago! The constant hail here is a big problem and I am thinking this might be a solution! Although I am not sure my HOA will allow it. Can you tell me if the foam would hold up and out-perform a shingled roof in our intense Texas heat, large hail, and constant tornadoes? Do you have any pictures as to what it would look like on a residential home with pitched roofs?
Typically, shingles are best on roof that have a high pitch. I’ve been in some of those Texas hail storms and the are HUGE! You should look for a style of shingle that does not break or crack when faced with large hail stones. Foam roofing is a solution geared toward low-slope roofs that require a continuous barrier with no laps or seams. All that said, foam roofing can perform well in hail storms because of its resilient surface.
I have a steep roof pitch. I have little money and my roof needs to be replaced. Is there no way a foam roof will work for my home.
If it’s possible to walk comfortably on your roof, the pitch is likely within acceptable constraints for a foam roof application. However, shingle style roofing is typically recommended for roofs of 4/12 pitch or steeper.
Is it possible to install solar panels over a sprayed foam roof? If yes, will the mounting structure holes cause leaks later on?
Yes! We have installed thousands of solar supports in Dura-Foam roof systems without failure. Interestingly, the interface between solar support and foam roof system is where the materials are thickest and strongest!
I did not know before that you can walk on a foam roof. My brother recently bought a home with a foam roof and got his Frisbee stuck on top of it, but he didn’t retrieve it because he thought that the roof would collapse. I’ll be sure to let him know about this.
I am awaiting a quote for a foam roof, (new roof on existing home). I believe there are 2 additional layers which will be placed over the foam itself, with the top being a UV resistant layer.
Another contractor, who I am asking to quote some interior re-modeling is telling me NOT to do a foam roof but to do a rubber membrane one. I want this to be a GOOD roof that should stand me in good stead for a # of years. I’m now unsure of what to do. Advice?
With the plethora of different roof materials out there, you are guaranteed to get varying opinions from each person you ask. You have two key variables: 1) Roof Material and 2) Roof Contractor. As a material, foam roofing is a proven product. However, it is very important to select a foam roofing contractor with a strong track record and history of honoring their guarantees. For example, Dura-Foam has specialized only in foam roofing under the same name for almost four decades. Whether you are rolling-out rubber membranes and welding miles of seams or spray applying polyurethane foam, skill and diligence of the contractor is of utmost importance to assure that the material performs according to specification. After identifying the best contractors, investigating the trade-offs between different materials will lead toward an educated decision.
My sister wants to make sure that her roof is properly insulated for her home to be warm this winter. It was discussed here that foam roofing is not as expensive and as she thought it would be. Furthermore, it’s recommended to hire a professional foam insulation technician for quality care.
Finally, polyurethane foam is a yellow type of foam for roofing, insulation, refrigeration warehouses, and foam boards. Foam Roofing is New Although the ground work for polyurethane foam was done by Otto Bayer and his team in 1937, polyurethane foam would not become available until much later. For latest repair epdmcoatings is better than best.
Thanks for explaining that a foam roof can support the weight of a person. Recently, our home has had some leaks in the roof and it’s causing some problems inside the house. I’ll have to look further into spray foam roofing.
It’s good to know that replacing a coating will prevent birds from pecking at your foam roof. My sister wants to make sure that her home is protected from the elements in the coming weeks. I’ll share this information with her so that she can look into her options for roofing professionals who can help her with this.
My kids had a new roof installed on a 1966 flat roof home in June. We had a huge storm yesterday and a decent sized limb fell and made some punctures which we knew was a possibility with the foam. They didn’t go all the way through but until they can get their SPF contractor out there to make repairs, should they put some kind of roof coating on the exposed punctures? We live on a houseboat and use a rubber roof coating on our roof. Would that be suitable if they do need to put something up there?
Hi Christina – to self-perform a temporary repair of the tree damage you described, you could use a high quality “polyurethane sealant”. This type of material is typically applied with a caulking gun. Clean-up the area the best you can by shaving-off a minimal amount of the damaged polyurethane foam exposing a solid clean surface. Also, clean-up the adjacent roof surface the best you can. Water with a scrub brush or rag typically works well. Assure that no air is entrapped under the sealant by working it into the area of damage using a spatula or rubber scraper. After the polyurethane sealant cures, apply a UV-resistant elastomeric coating in case the polyurethane sealant is UV-sensitive.
Hi! We are thinking of puttimg foam roofing on our warehouse roof due to the many benefits like reduced heat absorption and arresting water leaks. But our main reason is sound insulation from rain. Our contractor claims that SPF roofing can do the latter. Would you have any experience with this? And will a 1-inch layer with elastomeric paint do the trick? Thanks in advance!
Hi Erick,
Foam roofing helps a lot with general noises such as traffic and airplane engines. However, the sound of water droplets splattering on the roof surface may be something you need to test if you need a specific level of sound dampening. For example, install foam roofing on a test area. Then, simulate rain drops with a spray hose while measuring inside noise at the test area vs. existing roof area using a decible meter. Adding a layer of Densdeck (fiber reinforced, gypsum based roof substrate) over the plywood sheathing prior to installing a foam roof system will provide additional sound dampening. Densdeck has a secondary benefit of an improved fire rating as it is a non-combustible substrate. Lastly, increasing the thickness of the spray foam layer can also increase sound dampening.
Can a foam roof be used on a green roof under 6-12″ of soil? Will roots dig into the foam?
You could confirm manufacturer specs, but offhand I believe you will find that SPF is generally not recommended for below-grade applications where the product would be under hydrostatic pressure for extended durations.
Can you use foam on a deck to construct a pitch for water to flow off? And after applying foam for the pitch could I place a layer of roofing finish material or tile on the foam?
The deck has polyglas and a hot tar application. Now needs to be pitch to get water to flow off the deck