Roof Coatings DFT: Mil Thickness

Roof Coatings DFT: Mil Thickness

There are a ton of different types of roof coatings out on the market. The basic key to most of these roof coatings is the Dry Mil Thickness (DFT). Mil is a reference to thousandth of an inch thickness. One mil is one thousandth of an inch thick. To give you perspective, standard copy paper is about 8 mils thick. A standard credit card is anywhere form 20-30 mils thick.

DFT Guidelines

All manufacturers have guidelines on how thick their coating should be applied. Most often they are given in DFT. How they reach that thickness can vary greatly depending on how they are applied and the percentage of solids the particular material is. As a customer what you really want to know is what the DFT will be. This will give you a good idea as to how you should compare roof coating quotes between companies bidding on your project.

Quotes should include how thick the contractor is applying the coating and to what manufacturers specifications they are following. Our quotes state that we are installing the roof to the manufacture’s 10 year specifications. For instance, Gaco Western’s silicon roof coating is applied at 1.5 gallons of silicon roof coating per 100 square foot, which is approximately 22 DFT.  There are many other aspects that also matter when it comes to roof coating thickness.

Percentage of Solids by Volume

Roof coat thickness is only one aspect of roof coatings. The percentage of solids by volume or weight are also an important aspect. This means that if a coating has a 50% solids by volume, when you apply one gallon of coating about half of the coating cures off (leaving only half the material you applied). As an example again, Gaco Western’s silicon roof coating is 95% solids. 95% of the roof coating will still be there once it dries.

Fun fact: all liquids applied at one gallon per 100 square foot have a wet millage of 16 mils.

It is also important to consider how thick the coating can be applied in a single pass. Most acrylic roof coatings need to be applied in several passes. If you apply them too thick in a pass they will mud crack, leaving big cracks in the coating. Since polyurea roof coatings dry very quickly they can be applied in very thick passes, over 40-60 DFT.

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How is your contractor going to check and prove that he is applying the proper thickness? Using a wet mil gauge is the most common way, but you can also use a coating thickness gauge.

When it comes to roof coatings, don’t let someone sell you a quick paint job when you really need a roof coating. Call us today!

Condensation Control In Metal Buildings

Condensation Control in Metal Buildings

We often have interest regarding spray foam insulation for metal buildings or pole barns due to condensation coming from the roof underside. This condensation can range from very irritating rain drops on the head to damaging very expensive equipment which can cause thousands of dollars in damage. There are many ways to fix this including spray foam insulation, but let’s first look at what is causing this issue.

The Problem

Condensation generally occurs when warm, moist air comes in contact with a cold surface. In a standard pole barn you would find on most farms across the country, the inside of a non-insulated pole barn may have a concrete floor — but most do not. So if you have a dirt floor or even a concrete floor, this is where a lot of the moisture comes from. Very few concrete floors in metal buildings have a vapor barrier installed under them.

When I say vapor barrier, the most common would be a sheet of 6mil plastic sheeting. There are many different kinds, including some with fiberglass netting that may even go up to 10 or 15mils thickness. A lot of people think concrete is waterproof but that is far from the truth. Because of stack effect, moisture is drawn from the dirt underneath up through the concrete. Concrete creates a capillary effect (to be explained in a later blog), wicking moisture through it.

The Solution


While vapor barriers may work, you cannot install them after the concrete is poured. So to solve the problem you need to prevent the warm, moist air from reaching the cold surface.  Here comes the sales pitch! Of course insulation does the trick. And of course spray foam insulation is the best answer during construction of the building and most likely is the only answer after the building is constructed. Insulating the roof underside or the ceiling deck in an attic can stop the annoying drip problem.

Many metal building manufacturers offer varying solutions from insulation to “magic aluminum” tin foil that may or may not fix the problem. Unfortunately, many of these can and will cost more than the first choice of spray foam insulation. For more information on tin foil problems, check out our previous blog from our sister company, KC Spray Foam, on the topic.

So the next question you will ask yourself will be whether you need open celled or closed cell foam. But it’s easy: both work to solve the problem. Stopping the rain drops only takes a good spray foam contractor. Give us a call and put the umbrella away for good!

The Dangers of Spray Foam: From a Spray Foam Contractor

The Dangers of Spray Foam: From a Spray Foam Contractor

So this may not seem like a typical blog – when an industry professional writes a blog about how their product can cause issues. But I think it’s time to clear the air (pun intended) regarding the dangers of spray foam.

You don’t need to go far in a Google search to find a whole host of websites, YouTube videos, and newspaper articles regarding the dangers of spray foam insulation. Being an industry professional with almost 10 years of experience, I would be the first to tell you that there can be and will be problems with spray foam insulation when installed incorrectly. All it takes is one bad apple out of hundreds of thousands of good installations to give an industry a black eye. So I thought I would go over what they are and how to prevent them from causing problems.

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Spray Foam Problems

Fishy smell – The majority of the time when spray foam results in a fishy smell results from one of two things: improper mixing or their ratio is off. Spray foam is designed to be installed with the two parts at a one-to-one ratio. When this doesn’t happen, the foam never cures out to the proper end product. The second option comes from installing closed cell spray foam in too thick of passes which in turn may not let the foam cure properly. Most manufacturers will tell you to never install closed cell spray foam in lifts or passes more than two or three inches thick.

Charring or catching fire – As we just mentioned, closed cell spray foam needs to be installed in controlled lifts. Since closed cell spray foam creates an exothermic reaction when it is processed, this creates heat and if installed too thick can potentially create a fire hazard.

Respiratory issues – When spray foam insulation is installed, the applicators and helpers are required to wear the proper personal protective equipment (PPE). Once the product has been installed correctly and allowed to off-gas properly, spray foam insulation is a very safe product. While spray foam is as safe as the things that you come in contact with on a daily basis, you don’t want to be breathing it in while it is being installed. Now with that being said, some people who are hypersensitive to chemicals in general or who have asthma and related respiratory problems; while I would like to sell product to everyone, these people may want to look to other insulation options. I look at it like this: those without peanut allergies don’t worry about being in contact with peanuts. But for the population that is allergic should we stop growing and using peanuts? No, we simply need to take the proper precautions.

How Do We Prevent The Problems From Occurring?

This is the really easy part, do your homework: hire a certified, properly trained, and reputable contractor. That sounds easy, so how do you know if they are certified and reputable? Start with asking if they are SPFA certified. Next, find out what manufacturer they are buying their product from and check to see if they have completed the manufacturer’s training program. Not all manufactures have training programs and will sell product to just anyone. Spray foam insulation is not a “do it yourself” project nor should it be done by just anyone. We are manufacturing foam plastic insulation on the jobsite. This takes proper training, equipment, and skill.


However the easiest way to prevent all this is just to call us.


Air Barriers: Getting it Right

Air Barriers: Getting it Right

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There has been a lot of information over the years regarding air and vapor barriers. The information over these barriers has evolved quite a bit. I recently came across this article from covering a few of them and I thought I would add a few things to this thought process.

Joseph Lstiburek usually does a great job of breaking down technical engineer jargon, but I thought I would go a step or two farther and highlight what I think are some of the most important parts of this article. At the basic level this article talks about two different things: air barriers and vapor barriers.

Air Barriers

Air barriers are important because most insulations are fibrous (meaning they allow air to move through them), thus we need to add some kind of air barrier to stop the air flow. Think of it this way: during the winter you put on a nice wool coat and if you go outside it will keep you warm. But if a gust of wind sweeps by the air will pass through the wool coat and make you cold. The same idea is transferred to fiberglass insulation and cellulose insulation. This is why they need an air barrier to help them work properly.

Vapor Barriers

Vapor barriers are designed to stop the vapor from travelling through the wall cavity and soaking the insulation. Let’s go back to the wool coat idea again. Take that wool coat and soak it in a bucket of water then put it on. You will find very quickly that wet wool or wet fiberglass and cellulose conducts temperature very quickly. As Joseph Lstiburek points out, “Vapor is principally transported by air flow not by vapor diffusion. We needed air barriers not vapor barriers to control vapor flow. It took decades for that distinction to be appreciated.”

It was widely thought that vapor diffusion was causing insulation to become saturated with moisture when it was really air flow or air movement. He covers many different ways that have been tried or are currently being used to add an air or vapor barrier. While most of these will work if perfectly installed, in reality most of these do not work because they are not perfectly installed. Joseph points out that in the real world applications are just not matching the designed standards. Talk about labor intensive, check out this fluid applied air barrier:

What Really Works

So let’s cover what does work in the real world: spray foam insulation. Pretty much all of the wall assemblies mentioned here could easily be fixed installing open or closed cell spray foam. Both open and closed cell spray foam are an air seal or air barrier. While some people may think there is a lower cost way to stop air movement in a wall cavity, I would argue that most of these ways require great attention to detail which in turn equals great cost. Spray foam insulation quickly sprays into place filling cracks, holes, gaps, etc. air sealing the wall or attic assembly.

You may try to reinvent the wheel when it comes to air barriers, but you really need a good spray foam contractor!

Importance of a Good Subcontractor

You Need a Good Subcontractor

During the construction process you will be in contact with a lot of subcontractors. While sometimes I feel as though subcontractors can get a bad rap on the jobsite, most of the time they do not deserve it. During the construction process, you will be faced with making tons of decisions at a rapid pace. While a lot of these decisions will be made on cost alone, choosing a subcontractor based solely on that is a bad decision.


A subcontractor should be chosen on many different factors which also includes cost. I could generalize this blog for most subcontractors, but because we are spray foam contractors I will focus on them for this blog. Here are a few factors to consider:

Experience: Experience is a key factor in the spray foam world. Purchasing a rig on eBay and spending a few minutes watching YouTube tutorials does not make an experienced Spray Foam Subcontractor. My general rule of thumb here is finding someone who has been in the business full-time for at least 5 years. You don’t want someone learning on the job during your project.

Training: What kind of training has this subcontractor and their employees completed? The bare minimum here would be training from the manufacturer they purchase their products from. The next step would be completing SPFA certification. Do your homework and ask for documentation.

Proof of License and Insurance: Simply asking for proof doesn’t cut it. Get written proof.

References: Get a list of recent customers from the spray foam contractor and check them. Ask the customers about their good and bad experiences with the subcontractor. Did they show up when promised? Was the work completed in line with the scope of work or quote provided? Was the work done on time? A little careful listening can tell you a lot about the character of the spray foam contractor.

General Contractors: What other general contractors does this spray foam subcontractor work for on a regular basis? What major companies have they completed work for? Large companies have offices full of people on the lookout for potential problem subcontractors. They also have very strict rules before letting subcontractors onto their premise. Leaning on their experience can help you steer clear of issues.

Cost: I left this one for last for good reason. Too many people focus on the cost alone when choosing a spray foam contractor. Price is what you pay, value is what you get. The sweetness of a low price quickly fades when the work being done is not up to standard.

Like most things in life, doing your homework will create the best result when selecting a spray foam contractor for your project. Contact us today for any spray foam needs you have!

Rising Utility Cost Increasing the Value of Spray Foam Insulation

Rising Utility Cost Increasing the Value of Spray Foam Insulation


After reading an article from the Business Record, I’ve been thinking about some of what I would call the “core benefits” of spray foam insulation. I have talked many times in the past about comfort being the largest value of spray foam. And it is, but spray foam insulation has many values associated with it including lowering utility cost. As utility costs continue to rise it becomes an even better asset to saving you money.


Electric Rate graph


According to a CNS News article, Mid-American Energy has implemented the second part of a 3-phase plan in raising electrical rates $45 million dollars in three years. This goes back to the basic supply vs. demand problem. As of January 2014, the US has the smallest supply of electricity since 2007 with an increase in demand of over 14 million people. This problem is only going to worsen as time continues.

Supply vs. Demand

Not only is demand putting a pressure on supply, but environmental groups are mounting legal cases on any new coal-fired electrical plant plans. Many existing coal-fired plants are being taken offline due to legal pressure or expensive upgrade costs to pass tougher emission tests. This site shows a growing list of plants being taken offline.

This leaves us with three choices to increase supply: build new natural gas fired plants, wind generated farms, and lower usage. Natural gas fired plants are relatively clean burning, but when we use natural gas to generate electric power we are also creating a higher demand on natural gas, driving its costs up as well.

Use Less!

Adding spray foam insulation with other energy-lowering options can reduce demand. A properly insulated house or building using spray foam can lower heating and cooling costs by as much as 50%.

Demand per household is also up at this given time. Think about it: back in the 1970s we had one TV per house, one refrigerator, no computers or 4-5 cell phones per home. How many of you now have a refrigerator in your kitchen but also in your basement and garage? How many TVs do you now have in your home? We have all switched to compact fluorescent lighting but demand still increases because of all of the other things in our homes. The problem is it is only going to get worse – how long until we all have 2-3 cars plugged into our garages? That meter is going to spin faster than a Harlem Globetrotters’ basketball!

Spray foam insulation is an investment that will pay increasing dividends as time goes along. Remember, you buy spray foam insulation once, but you buy energy to operate your HVAC system every time it comes on and the costs always goes up over time. To start investing in a lower-usage future, contact us today!

Insulation and Knob & Tube Wiring

Insulation and Knob & Tube Wiring

This time of year Mother Nature reminds us how powerful she can be. We receive numerous inquiries from prospective customers wanting to know if we can inject spray foam insulation into existing walls. While we can most certainly do this if the wall cavity is empty, the first thing our Salespeople and Certified Applicators look for is Knob & Tube wiring within the structure. If there is any, we always recommend bringing in a certified electrician.

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While we are definitely experts in spray foam insulation, we would never undertake wiring a home. We here at Iowa Spray Foam always refer to a professional electrician for their services.

Why is insulation and Knob & Tube a bad combination?

Knob & Tube wiring needs space to keep it cool. When spray foam insulation (or any insulation for that matter) is installed around it, the insulation restricts the wiring from dissipating the heat in the wire when electricity is energizing the circuit. If the heat is not properly dissipated, the wiring could overheat and potentially cause a fire. This is part of the reason that the tubes come into play: they prevent the wire from touching the framing or other materials, preventing fires.

You must also keep in mind that some of this wiring could be as old as 80 years old. We have witnessed some homes where the protective insulation wrap around the wiring has fallen off or has even been chewed off by rodents. So while most people don’t really want to spend money on upgrading their homes, it is really a good idea.

Don’t believe us? See what This Old House has to say about Knob & Tube: “Faced with drafty houses and high heating bills, homeowners often add thermal insulation to their attics and walls. Insulation on top of knob and tube wiring is a major fire hazard.”  They go on later to state,  “In 1987, the National Electric Code prohibited the placement of insulation in contact with this type wiring.”

These concerns come into play not only inside a wall cavity, but also in attics, crawl spaces, or even basements when installing spray foam insulation. This is just another reason to make sure you are looking for professionally trained and certified spray foam insulation contractors for your projects. Call us at Iowa Spray foam for your next home project.

Building Science 101: Heat Transfer Methods and Flip Flops

Building Science 101: Heat Transfer Methods and Flip Flops

flip flops
I know that I have written a lot of blogs in the past years, but this may be one of the least intriguing. However, the topic is important.
There are three basic methods for heat transfer: conduction, convection, and radiation. We are going to talk about conduction in this particular blog and we will follow up later with the other two methods.
What is Conduction?
Conduction is a heat transfer method that requires two materials to be physically touching each other to occur. This is unlike the other two methods of heat transfer that can occur without physical contact.
An example of conduction includes putting a pan on a burner of a stove and turning on the heat. The heat from the burner or flame transfers through the pan’s metal, warming the food in the pan. Another example would be walking on the sand at the beach while barefoot. As you may have experienced, the sand is hot and it will transfer that heat to your feet. So to keep your feet from burning you put on a pair of foam flip flops.
Now that you have a basic idea how conduction works you are certainly wondering what this has to do with spray foam insulation. In fact, it has a lot to do with building construction in general or even more to the point, how your building can lose energy and be uncomfortable.
Thermal Bridging
Thermal bridging is heat transfer via conduction. Have you ever driven down the road and noticed on a cool, frosty morning that you can see the lines from the trusses on someone’s roof? Or maybe on the siding of the wall you can pick out every stud? This is also known as “Ghosting”.
The reason you can pick out every stud is because wood has an R-Value of about 1 per inch. So when we install an R-21 of spray foam insulation into the wall, the insulation slows down the convection of heat through the wall, much like the foam flip flop keeps your feet from burning on the sand. The wood stud allows it to transfer heat faster and thus you see the lack of frost on the wall where the stud is. This also works on roofs when insulating the underside of the roof in a vaulted area because the drywall is attached directly to the roof joist and the sheet is attached to the roof joist from the other direction.
How Do We Stop This?
We need to provide a thermal break between the wood and the exterior of the wall. This is done by attaching foam sheeting, or in some cases applying spray foam over the trusses in a complete manner. The picture below shows the spray foam insulation installed over the purlins on the roof underside. The purlins covered will not conduct thermal bridging here.
How Much Energy Are You Losing?
Keep in mind you have a stud every sixteen inches in an exterior wall. If you add those up you could have anywhere between 15-30% or more of your wall conducting heat transfer. The 2012 IECC code has this figured out. They allow for a provision to have an R-13 cavity insulation with an R-5 continuous insulation such as a foam board.
Adding spray foam to a home is just part of building a warm and comfortable home. Stopping conduction via thermal bridging is another key part. Before heading out to the beach this cold winter and putting on those foam flip flops, call a Building Science educated Spray Foam Insulation contractor to keep you warm and comfortable!

Spot Lighting Spray Foam Insulation and Recessed Can Lights

Spot Lighting Spray Foam Insulation and Recessed Can Lights

This week we’ll be talking about recessed can lights. There are many types and styles, so we will begin by breaking down the different types.


In Contact

IC, or In Contact recessed can lights are designed to be installed with regular insulation installed directly beside or on top of them. Notice that I said “regular” insulation, such as fiberglass or cellulose insulation, NOT spray foam insulation. Spray foam insulation is an air seal and works a lot better than “regular” insulation does. Because the spray foam doesn’t allow the heat to escape it can make in contact recessed can lights get very hot.

Most can lights have a thermal overload to protect them from getting too hot. The thermal overload shuts the light down when it reaches a certain level to protect the light from damage. However, these thermal overloads wear out over time and stop working. When this happens, the light stops working and you have to replace it. You may have noticed that some can lights turning off and then coming back on after a short while. This is the thermal overload cooling it off, then it kicks back on once it is cooled (it’s not a ghost in the house!).

Non In Contact

Non-IC or Non In Contact recessed can lights are not to be installed in direct contact with any kind of insulation. These are usually installed in interior ceilings between floors. You never want insulation of any kind near these can lights because it could cause a fire.

Air Tight

Another popular style of recessed can lights are Air Tight. Most conventional can lights leak a huge amount of air into and out of the conditioned living space. Pay close attention to the details for installation on these particular lights and make sure to use the proper trim ring to make sure these are air tight. In my experience, they still are not very air tight even when installed properly.

Most Recessed Lights

Most recessed can lights will be stamped or labeled on the exterior and interior of the can light indicating which kind they are. Here at Iowa Spray Foam, we like to use products like these can light insulation covers to protect the light and leave an air gap around them when spraying foam in an attic. After installing these boxes, we coat them with spray foam insulation, effectively insulating and air sealing them.

Whether you use spray foam insulation or traditional insulation, recessed can lights are not very energy efficient for several reasons. To install them, you have to cut a hole in your ceiling directly into the unconditioned space – allowing air to move back and forth. Second, can lights typically only provide light in about an eight foot diameter area. So in most rooms, you will require many can lights to light the area where one good ceiling-mounted light would do the job.

Most older can lights use incandescent bulbs or halogen bulbs which use more watts of energy and produce secondary heat. During the summer you can have many mini heaters in your ceiling, pumping heat into your home. I’m sure you can remember sometime in your past touching an incandescent light bulb and getting burned. Just image the heat from eight or ten of these during the summer and how much heat they are exuding, putting a heavier load on your air conditioner!

Having a good spray foam insulation contractor who knows how to handle recessed can lights is incredibly important. Good thing you know how to contact us!

Moisture Myths and Spray Foam

Moisture Myths and Spray Foam

Here at Iowa Spray Foam, we get a lot of questions about spray foam and appropriately so. One of our most common questions is about whether or not spray foam will cause moisture issues. The simple answer is no. However, let’s go into detail rather than just taking my word for it.

Myth #1

Some people assume that when spray foam is applied to a metal surface (like a metal pole barn) that the moisture will get trapped on the surface of the metal, causing it to rust out. This is not true.

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By using some basic building science logic, we can easily disprove this. Moisture movement requires air movement. When you have an air seal you stop the moisture movement. Spray foam is an air seal which effectively stops the moisture movement. Condensation occurs when warm, moist air hits a cold surface which then leads the moisture-laden air to reach its dew point. Insulating with spray foam stops the moisture-laden air from reaching the surface, keeping it from reaching the dew point and then the water vapor in the air does not turn into a liquid.

Do you want to test this yourself? On a hot summer day, fill a plastic or glass cup and a foam cup with ice water. Set them outside for an extended period of time. Which one condensates? Of course the plastic or glass cup will condensate, but the foam one doesn’t. But why? The foam prevents the cold water from meeting the warm air resulting in a lack of condensation.

So you may not believe a spray foam contractor telling you all about the great things about foam. How about a building science professional? John Straube, a building science professional from Building Science Corporation explains condensation and how it is related to insulation:

“Cold-weather condensation is primarily the result of outward air leakage. Diffusion usually does not move sufficient quantities of water vapor fast enough to generate a problem. To control damaging condensation inside enclosure walls and roofs, air barriers are used to stop airflow and vapor control layers (vapor diffusion retarders or barriers) are used to limit diffusion flow. Air leaking outward through the enclosure wall in cold weather will contact the back of the sheathing in framed walls. This condensation can accumulate as frost in cold weather, and subsequently cause “leaks” when the frost thaws and liquid water drains down, or cause rot if the moisture does not dry quickly upon the return of warmer and sunnier weather .In walls with sufficient exterior insulation, the dewpoint temperature of the interior air will be below the temperature of the back of sheathing: therefore condensation due to air leakage cannot occur within the studspace. If an assembly is shown by calculation to be safe against air leakage condensation (using the method described below), then diffusion condensation cannot occur, even if absolutely no vapor resistance is provided inside of the sheathing (i.e., no vapor barrier or other control layer), and even if the sheathing is a vapor barrier (such as foil-faced insulations).”


Moisture Myth #2

Myth: You have to use closed cell spray foam on metal pole buildings. Open cell spray foam will allow moisture to get to the metal surface.

Remember that open cell spray foam is also an air barrier. Sealection500, the open cell spray foam used at Iowa Spray Foam, only allows 0.001 L/sm2 of air to pass through at 50ps. 50 Pascals of air movement is equal to about 16 mph wind. So with a 16 mph wind a very little, almost unmeasurable amount of air is passing through open cell spray foam. Even when tested at 300 Pascals — or around 50 mph — a very small amount of air moves through open cell spray foam.


The Questions to Ask

The best question that needs to be asked but consequently never is, is: how do we control moisture in the building? Simple things like vapor barriers under the basement slab or in a crawl space can do the trick. Controlling and removing excess moisture due to cooking, bathing, and laundry goes a long way as well. Check out this video from Anderson Windows on other ways to eliminate moisture:



The next time someone tells you that foam insulation traps moisture, tell them they are all wet! A spray foam contractor as well as a building science professional proved it to you with a foam cup! Contact Iowa Spray Foam for all of your spray foam needs.