Roof insulation with foam: 5 main issues of an independent master

Adding foam insulation to your roof can be an affordable way to raise the comfort and energy efficiency of your house. Because of its superior thermal performance, foam insulation is growing in popularity among homeowners trying to cut back on their energy bills for heating and cooling. But taking on this project as a do-it-yourself enthusiast has its own set of difficulties and things to think about.

Making sure the insulation is installed correctly is one of the main issues when choosing foam insulation. In contrast to other forms of insulation, foam needs to be applied precisely in order to work at its best. Its efficacy may be harmed by gaps or uneven coverage resulting from improper installation. To avoid costly mistakes, it is imperative that you strictly adhere to the manufacturer’s guidelines and consider seeking professional guidance when necessary.

The decision between open-cell and closed-cell foam insulation is another important one to handle. Every variety has benefits. For example, open-cell foam is more flexible and lighter, which makes it easier to work with in some situations. Conversely, closed-cell foam has a higher R-value per inch and is more moisture resistant, which makes it perfect for places where moisture buildup or humidity is a problem.

For those who enjoy doing things on their own, cost-effectiveness is important. In comparison to traditional insulation materials, foam insulation may have a higher initial cost, but it can result in long-term energy bill savings. Determining whether foam insulation is a wise investment for your house can be done by weighing the advantages over the disadvantages, which may include potential energy savings and increased property value.

Furthermore, using foam insulation requires careful attention to safety. In order to avoid being exposed to dangerous fumes during installation, proper ventilation is crucial. Furthermore, it is advised to wear protective gear, such as goggles, gloves, and respirators, to reduce the health risks related to handling insulation materials.

Finally, before starting a foam insulation project, it is imperative to understand the local building codes and regulations. Adherence to these codes guarantees that your installation satisfies safety and performance requirements, which may have an impact on the insurance and resale value of your house. Clarity on local requirements specific to your area can be obtained by consulting with building professionals or local authorities.

We will examine the main difficulties that do-it-yourselfers encounter when applying foam as roof insulation in this article for "All about the roof." We’ll go over the five main problems that independent homeowners face most frequently: choosing the appropriate foam, making sure the installation is done correctly, controlling moisture issues, handling ventilation needs, and knowing local building codes. By addressing these typical problems, we hope to offer readers useful advice and solutions that will enable them to properly insulate their roofs with foam, improving their home’s comfort and energy efficiency.

Which is hidden under the name "foam"?

The polystyrene foam is commonly referred to as foam. However, it’s important to distinguish between extruded and pure polystyrene foam.

It should be clear from the name alone that polystyrene is a byproduct of styrene polymerization. Polystyrol appears colorless, elastic, and hard. He lacks low density and strong mechanical strength for stretching or bending. This material is used to make dishes and other household items, as well as lenses.

Polistyle foam is a type of foamed polystyrene that can have varying densities and is produced as sheets up to 20 cm thick. It is more expensive, more loose, and has a smaller range of use than extruded polystyrene foam.

The name of extruded polystyrene foam comes from the method of its production – extrusion, when the raw materials are squeezed through certain holes of the same size. More precisely: extruded polystyrene foam is a gas -saturated melt of polyethylene. It is produced in the form of sheets with a thickness of 30 to 70 mm, it can be different not only in density, but also in color. It is much more durable compared to the usual foam, has a groove system at the edges and is convenient to install – there is no need to fill out joints. In addition, his thermal conductivity is even lower – in fact, the lowest of all existing heater.

Extrusion is the method used to create extruded polystyrene foam, which gives it a consistent closed-end structure. Every cell has a diameter of between 0.1 and 0.2 mm at most.

In Russian, extruded polystyrene foam is referred to as EPPS, while in English it is known as XPS. Additionally, they are sandwich panels made of polystyrene that is sealed with a metal sheet or an OSB plate:

Additionally, handling this material is very easy:

However, the light blue Primplex plates are among the most well-liked XPS goods available in the Russian market. This material is fairly strong, having a high degree of frost resistance, stability in geometric sizes, and incredibly low water absorption.

Than the foam is better than another thermal insulation?

Let’s now address common misconceptions regarding polystyrene foam.

Thus, high thermal insulation is the primary and most significant attribute for which this insulation is valued. Manufacturers state that this is a coefficient of 0.20 W/MK for each of its individual types and 0.035-0.048 W/MK at 25C. However, water is the one thing that foamed plastics absolutely detest and absorb it fast. Furthermore, the remarkable method used to create the polystyrene foam allows for a water absorption of up to 350% of its mass. And there’s more than just this! Additionally, the insulation’s ability to retain heat is reduced the more moisture it contains.

However, in actual use, regular polystyrene foam insulation for roofs only lasts 10 to 15 years before losing significantly its ability to block heat. However, EPS, or extrusion polystyrene foam, is more resilient.

But out of all the roof insulation currently in place, the foam has the lowest thermal conductivity. The temperature of the 50 mm thick foam and EPPS sheets will be +5 °C even in cases of extreme frost. Added benefits over alternative heat insulators include:

  • Sound permeability.
  • Stable dimensions over time.
  • Ease of installation and cuts to the desired dimensions.
  • No need for wind protection.
  • Resistance to chemicals of various kinds.

Additionally, it’s fascinating to observe how extruded polystyrene foam is tested in a factory setting where it is submerged in water, heated to +40 °C, and then cooled to -40 °C. One year of operation is equivalent to each of these cycles. Consequently, extruded polystyrene foam manufacturers can state with confidence that their product can function as a subcutaneous heater for 50 to 80 years.

The fact that extruded polystyrene foam maintains its thermal insulation qualities even in the presence of water is perhaps its greatest benefit. Ordinary heaters typically last only a few years before they gradually lose their ability to retain heat, requiring the home to be heated more and more frequently if mistakes were made in the roof insulation. Not to mention other associated issues.

However, rodents can cause damage to the polystyrene foam in the roofing pie; they won’t live there, but they will move around in it. Unless you conceal these sheets from view:

Is the foam safe as insulation?

Officially, this material belongs to the category of environmentally friendly materials, which are those that don’t harm people or the environment. But let’s first decide which effects on the human body—prejudice and excessive anxiety—can be deemed harmful. You’re going to be really taken aback!

Such different concepts

Therefore, threshold and linear are the two basic concepts that are commonly used to evaluate the potential harm that certain substances may cause to the human body.

The threshold concept claims that all harmful substances in a residential building should be reduced to a level determined for each of them, the threshold, which is fixed by the value of MPC (maximum permitted concentration). T.e. This is the amount of harmful substance in the air that can already harm a person. Exceeding this threshold always leads to such negative consequences as a disease or even death. Let us give an example: the cheapest foam is chosen as a heater, it is mounted incorrectly, normal ventilation in the home is absent. Result: Sick liver in households. But in a well -ventilated house, no one feels harmful for a long time. T.e. The point is that the concentration of a harmful substance below the established threshold does not have a dangerous effect on a person, and with small toxins a healthy organism can easily cope. This is somehow to breathe in cigarette smoke from the interlocutor.

In all countries of the former USSR and modern Russia, construction standards and rules are based on the threshold concept. But in Japan, Canada, Germany, the USA and Belgium, the linear concept is at the head, the essence of which is that the harmful effect on the human body is linearly depends on the total absorption of a certain substance. T.e. At one time, cigarette smoke will really not have a significant negative effect on the body, but constant smoking – yes. The same applies to foam: if such a heater is on the roof and on the walls, then every day a person through the lungs absorbs the permissible style of styrene, which in a year is not so few. In a word, small concentrations of poison with prolonged use are also harmful. This is easy to show on the example of modern megacities: all the exhausts of transport and emissions of the plants themselves separately do not exceed the sanitary threshold, but still the townspeople do not live sweetly.

Reducing the maximum amount of styrene allowed in the living room by 594 times is necessary if the warming process uses the second idea rather than the first.

Naturally, polystyrene finds application in both the nation’s food industry and medical field. But keep in mind that the same concept—threshold—is used to calculate its toxicity. We merely point out that polystyrene and polystyrene are already out of use in many nations, and in some, it is even illegal.

A substance that is not excreted from the body

And this brings to mind that Stirol is a bad substance because it is not eliminated by the body. It is a condensed aromatic compound with gasoline yards in its molecule. Furthermore, contemporary scientists advise against using any foam or other polymerization products during the building of new homes because the threshold for Styroll’s substance to be present in the air should be lowered to such a low level.

Thus, we draw the following conclusion: styrene is poisonous to humans before anything that builds up in the liver. Ultimately, the issue lies in the fact that while the human body can effectively handle a typical toxin by breaking it down and excreting it through natural means (with the aid of the liver), styrene remains within the body and only builds up. As a result, only a linear threshold concept can be used with polystyrene insulation.

Furthermore, combustible materials should have the toxicity of combustion products assessed, per contemporary SNiPs. T2, or "moderately hazardous," is the value found in premium polystyrene foam.

99% polymerization

There is another point that not everyone knows about. The fact is that 100% polymerization of EPS is only a theory, but in practice it does not reach 98%. In addition, even the polymerization process itself – we turn it, because polymers are easily destroyed from ultraviolet rays, ozone, water, oxygen, heat and mechanical influences. Then, free styrene begins to separate from EPS and penetrates into the living room, albeit in a small concentration, but the heart and female health affects and not a little. And the most frequent problems from this element are toxic hepatitis, and all because of the cumulative properties of the styrene to accumulate in the liver, but not to be withdrawn.

Lastly, unique research conducted by the Russian Academy of Sciences revealed that, over the course of its use, polystyrene foam decomposes to a percentage of 10-15%, with 65% of the decomposed portion being styrene.

Exit – ventilation!

However, how could the foam that insulates the roof be harmful? Of course, no way, if this is insulation from the outside. Ventilation must be carefully considered if the attic is not used and the source is internal. However, the situation is dire if we are discussing an attic in a residential building with that kind of insulation. To put it mildly, we do not recommend doing this.

Alternatively, as in this project, it is wise to close the foam in front of additional insulation:

How to warm the roof with foam inside and out?

However, we have prepared a series of in-depth master classes for you to address this question.

The principal techniques for adhering the foam to the surface are:

However, two mounting techniques are mostly used. Glue

So, heat the attic roof appropriately:

As insulation for concrete roofs:

1. Choosing the right foam type 2. Ensuring proper application thickness
3. Addressing moisture and ventilation concerns 4. Understanding fire safety regulations
5. Evaluating cost-effectiveness and long-term benefits

A useful and efficient method to increase comfort and energy efficiency in your home is to insulate your roof with foam. Its superior thermal resistance, which keeps your house warmer in the winter and cooler in the summer, is one of its main advantages. Over time, foam insulation can reduce your heating and cooling costs by minimizing heat transfer through the roof.

But before you start this project, there are a few important things to think about. Make sure the roof structure is appropriate for foam insulation first. The best roofs for this kind of insulation are those with few corners or curves, that are flat or gently sloped. It’s critical to evaluate the state of your roof and whether foam insulation is compatible with it in order to prevent future problems.

The installation procedure itself is another crucial component. Although some homeowners might think about doing their own foam insulation, it’s usually best left to the pros. Achieving the best insulation performance and avoiding common pitfalls like insufficient coverage or moisture issues require proper installation.

Cost is a crucial factor as well. The initial cost of foam insulation is usually higher than that of conventional insulation materials. Yet, a lot of homeowners discover that the initial expenditures are justified by the long-term energy savings and improved comfort in their homes. It’s critical to balance these monetary considerations with the possible advantages for your particular circumstance.

Last but not least, think about how foam insulation affects the environment. Certain foam varieties might contain substances that are harmful to the environment. Making an environmentally friendly decision for your house can be aided by looking into eco-friendly options or speaking with an experienced contractor.

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What do you think, which element is the most important for a reliable and durable roof?
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Alexandra Fedorova

Journalist, author of articles on construction and repair. I will help you understand the complex issues related to the choice and installation of the roof.

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