Insulation is a crucial component for any residential or commercial building. From the high-rise apartments in the heart of the city to the suburban ranch houses and rural farmhouses, our homes need proper insulation to maintain comfort, reduce energy costs and protect our planet by cutting down carbon emissions. Among the several types of insulation available, foam board insulation stands out due to its unique features and numerous advantages. This article will explore foam board insulation extensively, discussing its types, installation process, benefits, and more vital information.
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What is Foam Board Insulation?
Foam board or rigid foam insulation is a versatile, high-performance solution primarily used for insulating walls, foundations, and roofs. These boards are made from several materials that offer different levels of heat resistance, strength, and permeability. Some popular types of foam board insulation are:
- Polystyrene Boards: Lightweight and easy to handle, these insulation boards are either of expanded or extruded type. Expanded polystyrene (EPS) offers moderate insulating properties, while extruded polystyrene (XPS) provides superior insulation.
- Polyurethane Boards: Known for their excellent insulating performance, these boards have a higher R-value (ability to resist heat flow) than other types.
- Polyisocyanurate Boards: These boards are treated with a fire retardant and offer incredible energy-saving properties.
Importance of Foam Board Insulation for Energy Efficiency
Poor insulation is a leading cause of energy inefficiency in homes and buildings. This inadequacy leads to substantial heat or cooling loss, resulting in an overworked HVAC system and higher energy bills. Installing quality foam board insulation offers a reliable solution for saving energy by:
- Reducing Heat Loss: The high R-value of foam board insulation minimizes heat loss during the cold months, helping maintain a warm and cozy indoor environment without placing an unnecessary burden on your heating system.
- Lowering Cooling Costs: In hot weather, a well-insulated house with foam board insulation will prevent heat from entering your interiors, reducing the strain on your air conditioning system.
How to Install Foam Board Insulation
Installing foam board insulation is a straightforward process. Here’s a step-by-step guide to help:
- Measure and Cut: The first step is to measure the space where you plan to install the foam board and then cut it accordingly using a knife or saw.
- Secure the Boards: Next, you place the cut board in the space, ensuring a snug fit. Secure the boards onto the wall or floor with adhesive or mechanical fasteners.
- Seal the Edges: To prevent air infiltration, use caulk or spray foam to seal the edges.
However, it's important to note that incorrect installation can lead to inefficient insulation. Hence, it's always wise to hire professional installers if you're unfamiliar with the process.
Top Benefits of Foam Board Insulation
Here are the primary benefits you can expect when opting for foam board insulation:
- Energy Efficiency: Foam boards have a high R-value, offering excellent thermal resistance per inch of thickness.
- Easy Installation: Foam boards are lightweight, easy to handle, and can be cut into different sizes and shapes for hassle-free installation.
- Moisture Resistance: Certain types of foam board, like XPS, resist moisture, making them perfect for damp locations.
- Structural Strength: Foam boards add structural strength to your walls, floors, and ceilings.
Frequently Asked Questions about Foam Board Insulation
How do foam board insulation work?
Foam board insulation works by providing a barrier between the inside and outside temperatures of a structure. The foam material contains millions of tiny air pockets that slow down the rate at which heat can transfer through them. This means that in the winter, the warmth from your heating system stays inside the house, and the cold air stays outside. In the summer, the process is reversed, keeping your air conditioned air inside and the heat out.
What's the best way to install foam board insulation?
The best way to install foam board insulation depends on where you’re installing it. For example, foam board installed in a basement or exterior wall might require different installation methods than foam board installed in an attic. However, the general steps typically involve: measuring and cutting the foam board to fit the space, attaching it directly to the framework of the area being insulated, and then sealing any seams with a foam sealant or tape. Always remember to check local building codes or consult with a professional before beginning this kind of project.
Can foam board insulation be painted or covered?
Yes, foam board insulation can be painted or covered. However, if you're intending to paint the foam board insulation, make sure to use a paint that's suitable for foam as some types of paint can damage the insulation. If you want to cover the foam board insulation, you can do so with drywall or paneling. But it’s important to note that any covering needs to be fire-resistant, as foam board insulation is highly flammable.
How do you cut foam board insulation?
Foam board insulation can be cut using a utility knife, a handsaw, or an insulation knife. For straight cuts, consider using a straightedge or a square to guide your cut. Keep the cuts as clean and accurate as possible.
How long does foam board insulation last?
The life expectancy of foam board insulation varies depending upon various factors, including the type of foam, installation location, and environmental conditions. However, if properly installed and protected, foam board insulation can last for over 50 years. It is also possible for it to last indefinitely if it remains dry and undamaged.
Can foam board insulation get wet?
While foam board insulation has some resistance to water, it is generally not considered waterproof. Long-term exposure to moisture can reduce its insulative properties and lead to issues with mold and mildew. In areas with high moisture levels, it is recommended to use a type of foam board insulations specifically designed to handle such conditions, such as extruded polystyrene (XPS).
Does foam board insulation need a vapor barrier?
Whether foam board insulation needs a vapor barrier largely depends on the type of foam board and where it's being installed. For example, extruded polystyrene and polyisocyanurate foam boards often provide sufficient resistance to moisture and don't typically need an additional vapor barrier. However, locations with high humidity or extreme seasonal changes might benefit from an additional vapor barrier. It's always a good idea to check local building codes or consult with a professional.
Is foam board insulation effective for soundproofing?
While foam board insulation is primarily used for thermal insulation, it also has some soundproofing properties. Its dense material and unique structure can help to reduce the transfer of sound waves through walls or floors. However, for significant soundproofing, other material or methods specifically designed for sound isolation should be considered.
Pros of Foam Board Insulation
Energy Efficiency
Thermal Insulation
Foam board insulation is an outstanding insulator, boosting the energy efficiency of homes and buildings. Its R-value, or its measure of thermal resistance, is comparable to or higher than other insulation types. It impedes heat flow, maintaining a constant indoor temperature regardless of outdoor conditions.
Energy Reduction
Due to its insulating characteristics, foam board insulation can significantly reduce the amount of energy utilized to heat or cool down a space. This reduction in energy use directly translates into savings on energy bills.
Easy Installation
Lightness and Flexibility
Foam board insulation is light and easy to handle, making it a more manageable choice during insulation installations. Its flexibility enables easy shaping, fitting, and cutting, accommodating various space sizes and shapes.
Other than a knife or saw for cutting the foam to the appropriate size, the installation of foam board insulation requires few other tools or resources, which contributes to its ease of installation.
Sound Insulation
Besides thermal resistance, foam board insulation also provides superior reduction of outside noise infiltrations. The dense material absorbs sound waves, reducing the amount of noise that can penetrate through walls and floors, resulting in a quieter indoor environment.
Moisture Resistance
Unlike some other insulation types such as fiberglass, foam board insulation is resistant to moisture. This feature decreases the likelihood of mold and mildew growth, protecting structural elements from the damaging effects of excessive dampness.
Cons of Foam Board Insulation
Environmental Impact
Non-Biodegradable
Foam board insulation is made from non-renewable petroleum products and it's not biodegradable. Once installed, it can last for a very long time, but when it's discarded, it can take hundreds of years to decompose.
Greenhouse Gases
The manufacture process of foam board insulation contributes to the release of greenhouse gases. Some types of foam board insulation also off-gas harmful chemicals which can have adverse health effects.
Fire Risks
Foam board insulation is highly flammable. Although many come with a fire retardant, these materials can become ineffective over time. This insulation type should not be left exposed and should always be covered with a fire-rated material.
Cost
Foam board insulation tends to be more expensive than some other traditional types of insulation, such as fiberglass or cellulose. While it can reduce energy costs in the long run, the upfront costs may be prohibitive for some homeowners.
Limited Compatibility
While foam board insulation is a versatile product, it cannot be used in all application scenarios. Its rigid nature makes it unsuitable for irregularly-shaped areas, and certain types can degrade if they come into direct contact with concrete or other specific materials. Therefore, it may not be the ideal solution for every insulation need.
Myths and Misconceptions About Foam Board Insulation
Foam board insulation, also known as rigid foam insulation, is commonly used in residential and commercial buildings for its ability to effectively reduce energy consumption and improve indoor comfort. However, misconceptions about this insulation method often cloud people’s judgement about its use. Below are various myths you might have heard about foam board insulation and the truth behind each one.
Myth 1: Foam Board Insulation is Inferior to Other Types of Insulation
Misconception
Many individuals erroneously believe that foam board insulation is inferior to other forms of insulation, such as fiberglass and cellulose. This belief often originates from the misconception that foam board insulation offers less insulative value compared to its counterparts.
Reality
Contrarily, foam board insulation has a high R-value, denoting its resistance to heat flow. It provides superior thermal performance compared to other insulation types per inch of thickness. Thus, even if you have limited space for insulation, foam board insulation would still yield excellent results.
Myth 2: Foam Board Insulation is Expensive
Misconception
The misconception that foam board insulation is costly arises from comparing its initial purchase price to other insulation materials. The misconception is furthered by the perceived complexity of the installation process.
Reality
Though the upfront cost of foam board insulation may be higher than some alternatives, it can save you significant amounts of money over time through reduced energy costs. The thicker, more efficient insulation foam board significantly lowers the need for heating and air conditioning, thereby reducing energy bills. Moreover, it is a straightforward DIY job, necessitating only minimal tools, and saves labor costs for installation.
Myth 3: Foam Board Insulation is Flammable
Misconception
People often misconceive that foam board insulation materials are highly flammable and pose a significant risk of causing house fires.
Reality
Most foam board insulation panels are treated with fire retardants to minimize their flammability. However, as with other insulation materials, if subjected to an extreme source of heat, foam board insulation can catch fire. As a precautionary measure, foam insulation should never be left exposed and should always be covered with a fire-rated product, such as drywall or plaster.
Myth 4: Foam Board Insulation Can Cause Water Problems
Misconception
A common fear propelling this misconception is that foam board insulation traps moisture, leading to condensation, mold growth, and structural damage to a property.
Reality
Properly installed, foam board insulation can actually help manage moisture problems. Its compactness means it forms a more effective vapor barrier compared to loosely-filled insulations, reducing the risk of condensation. However, it's important to ensure that seams are sealed correctly during installation to defend against potential moisture infiltration.
Myth 5: Foam Board Insulation Harms the Environment
Misconception
The notion that foam board insulation is detrimental to the environment stems from the manufacturing process involving the use of some chemicals.
Reality
Modern foam board insulations are made using environment-friendly blowing agents. In fact, by improving energy efficiency and reducing carbon footprint, foam board insulation contributes more towards environmental sustainability. It's worth noting that the overall environmental impact of an insulation material includes its performance and lifespan, not just its production.
In conclusion, when looking for suitable insulation for your home or business, it’s essential to look past common misconceptions. Foam board insulation has proven its effectiveness and efficiency in a broad range of applications and environments. By understanding the reality behind these myths, you can make an informed decision about this suitable material for your insulation needs.
Summary
So, it seems that when it comes to insulation options, foam board insulation is a really viable choice. It provides excellent thermal resistance to protect your home from extreme weather conditions. The benefits including ease of installation, improved energy efficiency and long-lasting durability make it an outstanding option for homeowners on a quest for better insulation.
Foam board insulation also stands out because of its remarkable versatility. It can be used in walls, roofs, and foundations, making it a go-to for a range of different insulation projects. Not only does it provide great insulation, but it also acts as a vapor barrier to keep your home free from unwanted moisture.
All these advantages make foam board insulation a clear winner in the insulation game. Whether you're building a new house or looking to improve your existing one, foam board insulation could be your ideal partner in achieving perfect comfort. It's all about ensuring that your home is as energy-efficient, comfortable, and protected as it can be, and this stuff really does the job right!
About US Quality Construction
Polyisocyanurate (PIR), Extruded Polystyrene (XPS), Expanded Polystyrene (EPS) or Styrofoam?
When building or renovating a high-performance building envelope there are really three main kinds of rigid foam panels you are going to have to choose from - Polyisocyanurate known as Polyiso (PIR), Extruded Polystyrene (XPS) - often called Styrofoam - and Expanded Polystyrene (EPS).
Before choosing, you should know exactly what you expect these foam insulation panels to do, to make sure you buy and benefit from the right one. These three products we're comparing here are all petroleum-based, but their characteristics, performance and ecological impacts vary significantly. Alternatively, depending on application and budget, you could always choose natural Green Insulation Products, Like Hemp Insulation panels or Batt Insulation or mineral wool - demonstrated here in roof insulation.
Polyisocyanurate foam panels:
PIR, polyiso, or ISO, is a thermoset plastic product typically produced as a foam and used as rigid thermal insulation panel - most often with aluminum foil facing. Thermal performance is rated at R6-6.5 per inch, but don't count on that if your winters are cold for the reasons we're about to explain. Most insulation products actually perform a bit better the colder it gets but polyisocyanurate breaks that rule. As of about 15°C its performance starts to deteriorate, and badly. By the time you get down to the -20s Celsius it's nowhere near that. It can be a great product to use as long as you keep it warm, which is a really odd thing to say about an insulation product.
The news of Polyiso's R value petering out when you need it most still hasn't permeated entirely through the building industry, so you still see it being installed occasionally on the exterior of walls in cold climates. It won't offer nearly the thermal protection you think it will in the dead of winter, and it may cause moisture damage due to its lack of permeability.
Polyiso insulation boards are the most widely used low slope, above-deck commercial roofing insulation. As a versatile choice for commercial roofing applications, polyiso is designed to be part of any modified bitumen, built-up, or single-ply roofing system. Polyiso products feature a facer for high strength and excellent absorption for both hot mopping and adhesive attachment methods. The product also is designed to perform well with mechanical fasteners, possibly under Green Roof membranes.
Polyiso Foam Panel Insulation Conclusion: In real terms, using polyiso foam insulation panels is probably a poor choice if your winter temperatures dip below 50°F or 10°C. To put that statement into perspective, a wall or roof assembly in Chicago was tested for the whole of December then averaged out. The first assembly using 2" Polyisocyanurate foam panels was compared to the same assembly using 2" of EPS foam and was found to be losing 30% more heat in this study (see below)!
XPS - Extruded polystyrene foam panels - The blue, pink or green ones (eg. Styrofoam):
XPS is Rated at R5 per inch, but it will off-gas and lose some insulation performance over time - especially below-grade and when tested in real-world applications. Above grade XPS foam acts as a vapour retarder (and becomes even less moisture permeable the thicker it is - 1 inch is about 1 perm, 2 inches about .5 perms); when taped it can act as an air barrier; the manufacturers and standardized testing state that it does not absorb moisture, nor is it affected adversely by it. However, with some of the EcoHome team having real world experience to the contrary, we "dug-deeper" and found that many contractors have also noticed potential issues with XPS foam boards retaining moisture, backed up by reports like this citing a large source of correlated testing and which would lead us to conclude that XPS rigid insulation panels should be avoided for below-grade applications like basement insulation - which is the opposite of much of the information out there.
Note: 1 perm and 60 ng are U.S. and Canadian equivalent rates of permeability, below that rate of permeability classifies a material as a type II vapour retarder, suitable for residential construction.
Also, rather regrettably for traditionally produced XPS, the hydro fluorocarbons (HFCs) most commonly used as blowing agents are far more damaging to the climate than those used with other rigid foam insulation boards. Some manufacturers speak of a transition to more eco-friendly foam insulation blowing agents; that will be great news when it happens across the board! And credit where it's due, the "real" Styrofoam, as in the DOW Chemicals blue product, is now manufactured with HCFC blowing agents which have 94% less ozone depletion potential. As HFCs have a global warming potential (GWP) that is times worse than carbon, this really does demonstrate how important it is to choose rigid foam insulation boards very carefuly to reduce their environmental impact. All XPS panels are not equal!
EPS - Expanded polystyrene foam insulation boards:
Rated at R4 per inch; EPS foam insulation boards are more permeable to air and moisture than XPS, but it doesn't retain moisture to the same extent because of it's more closed cell structure and it's breathability which lets it dry out. Two inches of EPS foam board has a moisture permeability rate of between 60 and 75 ng (1 to1.25 perms), which is on the cusp of qualifying it as a type II vapour retarder, but on the more 'breathable' side of the scale which we would probably consider a good thing in most applications.
For reference sake, the traditional 6mil polyethylene vapour barrier has a permeability rating of 3.4 ng, making it about 18 times more vapour resistant than building codes allow.
The permeability of EPS can be handy at times if you want to add insulation to an existing wall assembly but are worried about trapping moisture, like retrofitting the exterior of buildings with additional insulation. Though to be absolutely sure you may be better with a mineral wool board which lets moisture pass right through - it all depends what moisture barriers are already in place or ar about to be installed.
The lower stated R value of EPS compared to XPS is in a way compensated for by having a higher R value per dollar, as it is somewhat cheaper. If you're not worried about losing an inch of space here or there, you'll get a higher R value with EPS for the same amount of money, albeit with a thicker wall, and this R-Value also stays pretty consistent over time - unlike XPS which tails off as it ages.
The performance of EPS may drop slightly when it's wet (reports I've seen indicate somewhere in the area of 10-15 %, so nothing too catastrophic), it will also dry out just as quickly as it got wet and return to its original performance. But there is nothing wrong with putting a little effort into keeping it dry if you can. The GWP of expanded polystyrene blowing agents is about 7 times worse than carbon, but that's a lot less than being times worse like standard XPS is. There is also the potential for a miniscule amount of off-gasing of some chemicals including potentially troublesome brominated fire-retardants from EPS foam products used in construction, but speculation as to whether or not this poses a significant risk to health doesn't seem to be based on any hard facts or testing. We'd be really interested to find any verifiable sources for EPS chemical off-gassing testing - if you find any please post them to the comments section below - as we are starting to think that EPS foam may arguably be the most Eco-Friendly insulation and this may sway our thinking against it.
Additional considerations with polyisocyanurate:
Polyisocyanurate foam insulation panels come with a layer of foil on each side to keep the gases in, so there is the potential to solve a bit of a growing problem in wall assembly durability. Foil is a vapour barrier and a very good one at that, it fact it stops even more moisture than the normal 6 mil polyethylene normally used. So if you use it on the interior of a high performance stud wall design, you won't need to add an additional vapour barrier.
Here is the fun part - Since there is foil on either side of the panel, you end up with a harmless second vapour barrier, which is usually heresy in building design. But this can help in summer months when there is a risk of the vapour drive reversing due to air conditioning during hot humid weather. Any inward-bound moisture would be stopped at that inner layer of foil, which will be warmer than the foil on the other side, so you reduce your risk of summertime condensation.
That foil is the reason it can be problematic on the exterior, as you would be adding an exterior vapour barrier where you likely don't want one.
On the good news side, the GWP of blowing agents in Polyiso is similar to those in EPS, and in the right circumstances its R value is significantly higher, which deservedly or not helped earn it the reputation of being the 'greenest' foam. It can be a great choice when kept above freezing and away from moisture - so above grade for sure, and it makes a great interior thermal break when it's kept a bit warmer by batt insulation in stud cavities.
Being petroleum based should not result in foam being condemned by green builders on principle alone; it should be looked at in perspective. There are other great types of insulated sheathing (mineral wool, wood fiber and fiberglass to name three) and each will have their own benefits, drawbacks, carbon footprint and embodied energy through manufacturing, so even the greenest of the green will have some measurable impact.
It takes energy to save energy, and manufacturing insulation is arguably one of the more noble things we currently do with fossil fuels. If you really want to go into depth about the tested performance values of Polyiso Foam panels in hot and cold clinates compared to EPS and XPS foam Insulation panels - see the article from Building Science Corporation here
An alternative to foam: mineral wool / rock wool rigid insulation panels:
The only rigid board insulation that is not a petroleum-based foam product shown in the main photo above is the brown one, which is mineral wool. It is a recycled product made with the stone dust from industrial blast furnaces.
Like any particulate, it is best not to inhale the fibers while installing rock wool insulation board, so like any batt insulation we recommend using eye protection and a mask, not to mention gloves to prevent skin irritation.
As an insulation it is non-toxic, and unlike foam products there are no blowing agents that will off-gas into your home. That means it can lead to cleaner indoor air quality, and the R value will never change, whereas foam products will deteriorate over time as the gases escape.
Mineral wool is rated at about R 4, it is unharmed by moisture, it is not a vapour barrier at any thickness, nor is it an air barrier. It also provides better soundproofing, and being made with stone, it is fireproof.
Not being affected by moisture makes it is a great choice for retro-fitting insulation when finishing basement, either interior or exterior. It is also something of a fool proof exterior board insulation when renovating, as it will not trap moisture from the interior inside the wall.
In batt form is it a common alternative to fiberglass for its higher R value, and easier installation (at least for doing a good job) It does however cost more than fiberglass per batt.
In conclusion - Which rigid insulation panel is best?:
Our personal overall preference due to its recycled content and versatile applications is probably mineral wool, but as for the petroleum plastic rigid foam insulation products - polyisocyanurate gets top marks for being 'eco' if you are in a warmer climate and can handle its moody disposition.
EPS foam is versatile, great for below-grade applications and in the middle ground for performance, financial and ecological cost, and whilst XPS foam is a top performer on paper it comes with some unfortunate environmental baggage for which we'd probably rate it in last place. As soon as XPS completes its transition to less harmful blowing agents, I'm sure it will be welcomed into the green building community for above-grade applications.
Now you know more about building envelopes. Read more in the Ecohome Building guide and the pages below, and watch more green building videos here on the Ecohome YouTube channel
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See the Ecohome video guide for high performance wall construction
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The difference between air barriers and vapor barriers
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Choosing the right house wrap / weather barrier, which is best?
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Are there energy savings from foil radiant barriers? Where should radiant barriers be used?
And sign up here for a free Ecohome Network Membership!
W
Are fire retardants added to polyiso, and if so do they off-gas? I'm thinking of using it on a roof deck where there is venting at a headwall with windows above.
a couple of corrections might help here. Mineral wool has Formaldehyde, while other building materials like OSB, Polyiso, XPS, etc. all have fire treatment. the offgasing from these is like the offgasing from formaldehyde, well within any health regulations, no Polyiso wont be a problem.
The cold temp comment is a bit off. the reality is that the temperature which is mentioned should be qualfied as the mean temperature between hot side and cold side of an insulation product, so when it is 0 Deg outside, and the inside temp is 70deg, the means you evaluate insulation thermal R value is 35 deg. Polyiso experience almost no drift in R value in this scenario. those that explain it with just outside temp are misleading you. Polyiso actually increases in thermal resistance as it goes from 75 mean to 40deg mean, then starts to drop off after that. So, outside temps have to reach -30deg or more to really see a reduction in thermal values.
Featured content:Why is Coil Handling Equipment Better?
If you are looking for more details, kindly visit XPS foam board production.
M
Wasn't Grenfell Tower clad in PIR (Polyisocyanurate)? That cladding seemed to be burning very well indeed, unfortunately. It looks like the flammable cladding at Grenfell was the main reason that the fire spread so quickly & engulfed the building. It's hard to believe that building industry professionals were paid good money to wrap a tower block in flammable plastic.
B
Grenfell is still in litigation, but from what I know, it was an improper combination of polyiso and a non-fire-rated ACM panel that was not approved by the code officials. But still allowed to be installed as code officials were not present to catch the error. Whether or not the manufacturers and contractors did this knowingly will be the sticking point of culpability and blame.
Either way, polyiso has been tested in over 100 different configurations for NFPA 285 compliance and can be used with a fire rated core ACM panel.
Here is a testing report from the industry leading polyiso manufacturer if you want further data.
https://www.hunterpanels.com/docman-categories/technical-documents-wall-xci/baw-sheets/baw--cg/-concrete-masonry-wall/file
Z
No, polyiso does not burn & is the best fire resistance out of the 3 types. Grenfell cladding does not seem to have an element on each floor to compartmentalize the fire.
B
Actually, British code creates a 2-hour fire wall on all six sides of each unit, which completely compartmentalizes individual units from its neighbor. This code consideration eliminates the requirement or inclusion of sprinkler systems.
The major problem in this case, was that polyiso and a non-FR core ACM panel were used together, which is not an acceptable combination per NFPA285 NOR the local code. On top of that, the ACM cladding was created to emulate columns with large voids, and created a chimney effect. Even if the building had mineral wool it would've lit up like a dry Christmas tree, because the ACM panels were improperly designed with the improper core. Fire rushed through building and blasted through the weakest area, the windows and engulfed each unit from the outside.
M
I think you need to do some more reading. Grenfell Tower was clad in PIR & it most definitely burned, despite the predictions of "experts" such as yourself. There may well have been additional problems such as you suggest, but the fact remains that wrapping a concrete tower block in flammable plastic turned a safe (if ugly) building into a death trap. Who in their right mind would fail to see the dangers of wrapping a building in flammable poly-anything? The building industry has blood on it's hands - it collectively let us all down.
And the biggest culprits are folk such as Watt Hertz who blandly assured us that PIR "doesn't burn". People believed them - but it was a lie - it DOES burn.
As a result of that, around 100 people died. Some of them may have died from cyanide poisoning from the gases given off by Polyisocyanurate as it burned. We weren't warned about that by the industry "experts" either, were we?
Shameful.
Mike, have you seen the fire testing that the UK did comparing similar assemblies with Polyiso vs. mineral wool. when you have flamable cladding, the end result cant be distinguished, they both would fail. it was the cladding that spread the fire, not the polyiso. pictures of fully burned cladding areas show polyiso still with its original color, just chared on the surface. almost all cladding type assemblies will pass NFPA285 (a proven barometer for fire safety for many, many years) with polyiso behind them.
It is unfortunate that some people say it wont burn, heck even metals can burn. imagine building with wood?! buildings have all kinds of combustibles, from air barriers, to claddings, vynil, carpet, furniture, electical equipment,............ on and on. the point of NFPA is to provide guidance on safe time to evacuate, not to prevent any combustion, that is impossible at this point in time for all elements. dont pick on one, fire safety is about the entire structure.
M
Here you go - this might help to explain what happened. This is the PIR cladding burning at Grenfell Tower. It's pretty clear that the plastic cladding is burning with great enthusiasm, isn't it?
http://www.bbc.co.uk/news/u...
M
There seems to be contradictory information about the material used. This article says that PIR was used.
However other reports say that it was Reynobond PE, but even if that is true, it's surely obvious to anyone that it wasn't a safe material with which to wrap a tower block? I'm not interested in whether it's a good choice for a low rise block, that's irrelevant
I have also seen on TV that the substance used was PIR, though with so much information around it's a a job to remember where we heard what. But one fact is indisputable - it burned ferociously. And it apparently passed all the "tests" that were required.
Anything that begins with "poly" is a plastic, right? And all plastics will burn, though some more readily than others. It's never going to be safe to wrap a tower block in plastic - simple as that. It needs to be as fire resistant as asbestos or concrete, otherwise it simply makes the building a much greater fire risk than it was before, albeit a little prettier - till it catches fire.
Whether the material used was PIR or PE, it was totally inappropriate & caused a small fire to engulf the block. Surely the simple question we need to be asking is this;
"Who in their right minds could have ever thought that wrapping concrete blocks in flammable plastic of any kind was a good idea?"
Never mind whether or not this "good idea" was a good use of millions of pounds of public money!
J
Excellent information! Question: I will be insulating the inside front tack/dressing room of my aluminum bumper pull horse trailer. Do you recommend the EPS Polystyrene? or the polyisocyanurate? I live in a cold climate so keeping the space warm is important. Also wondering if I should use a construction adhesive to adhere the insulation to the outside walls.
Hi Judi
I wouldn't go with the polyiso since it doesn't work as well when its cold. I'd use EPS, or even XPS. I don't recommend XPS often as you probably read above, but it has a higher R value per inch and you will clearly have limited space and want to insulate it as best as you can in the space you have. And yes, you could attach it with an adhesive, just make sure to choose one that suitable for the application, not all of them are, so read the tube or ask for advice when you're in a building supply store.
And, another option you may want to consider would be spray foam. Demimec has switched blowing agents so it is now far less polluting, and given that it is for a trailer, you may be able to get it done cheaper by taking it to an installer rather than them having to come to you.
Hi Elisa,
That's a good suggestion, but I thought a problem with Rockwool in this situation is that it would be difficult to attach it with an adhesive, so Judy would need to come up with some other method of fastening it; that might be difficult to do with the thin walls of a horse trailer and not have the ends of screws poking out the other side.
We do like Rockwool for a number of reasons (it's made with recycled stone dust, it's not harmed by moisture, etc), but in this case it doesn't seem like the best option. But I like that you thought of that, thanks!
R
you state that the board has foil on either side. which way do you install the foil? facing interior or exterior??
Wait... someone just suggested that you may have meant to say . foil is on EACH side
Thanks
It's worth mentioning that Mineral Wool's Global Warming Potential is higher than that of either EPS or Polyiso. It may be a good use of a waste product (slag, glass, ceramic) but its production process is seriously energy-intensive.
G
Good afternoon, I am writing from Montreal Quebec, we have recently solicited a quote to replace a 30,000 square foot steel deck roof on a commercial building. The roofers have recommended using 2 1/2 inch ISO insulation on the roof. Not knowing what this product was I researched it and fell upon your website. I am now very skeptical about using this product on the roof where our temperatures are well below 15 degrees C in the winter. Called 2 roofing supply stores and both seem to say it is the main roofing insulation for this type of roof. They had no idea of the pitfalls of ISO when exposed to the cold. Since this material would be installed outside on the steel deck, separated only by a vapour barrier I was really questioning its efficiency for the Montreal Climate??? I'm also concerned with the weight on the roof during the winter months (snow, rain and ice). How will this affect the product. Would it crush the gases out prematurely? What other type of instulation could be used instead of the ISO?
Thanks Gennaro
Hi Gennaro,
Polyisocyanurate on a roof will work as an insulation, just not as well as most people may think. And it isn't a great surprise that an installer hadn't heard that the performance falls off in colder weather since manufacturers present their 'best' results from testing, and in warm conditions it does offer R6-R6.5, so that is laregely the 'accepted' R value of polyiso in the industry.
Some builders that are aware of the performance concerns have begun including a final layer of rockwool on top of the polyiso to keep it warmer so that it continues to offer up around R6 per inch.
As for how much to install, we have come to realize that for the most part, regional building codes are about half what we ourselves would do. So our recommendation would be to find out what is specified in the regional Building Code (which is a bare minimum) and probably double it.
K
Hello all. I thought I was confused before, I have less of an idea of what to do now. I have a seasonal home in VT. In winter, the house is unheated. Always find moisture in the basement when we arrive in June. Was going to insulate the basement walls with 2" Polyiso until I read this blog. Can anyone recommend how to insulate a concrete block basement wall to alleviate the moisture problem? The ceiling is uninsulated. Excavating around the perimeter may not be possible due to concrete platforms and stairs around 1/3 or more of the perimeter. It sometimes gets as cold as -20 here and can be below 0 for weeks. What should I do?
Hi Bobby
This article is based on findings from the building science community and we have no motivation to provide anything but accurate information. Can you say the same?
Given your fierce defense of polyiso and your ability to rhyme off numbers, we are wondering, and please be forthcoming - do you profit in anyway from the sale of polyisocyanurate insulation?
Are you employed by a company called Hunter that provides polyiso panels?
We look forward to seeing documentation to back up this myriad of claims (independent third party documentation, not from a company you may work for), as well as an honest answer as to any affiliation you may have with the industry that would help us understand why your nose is so far out of joint. Thanks.
D
One element of exterior foam insulations (both above and below grade) that I am really struggling to evaluate is insect damage. We live on Vancouver Island and our current house has exterior foam above the roof deck. This foam layer is a very desireable home for carpenter ants, who make nests in it and then end up in other parts of the house. As we design a new house for the same property, I am really striuggling to determine which foam or mineral wool insulations are least likely to pose a problem like this. We will be insulating below the walkout basement slab and outside the basement foundation walls, and possibly on the outside of the above ground framing. Any ideas, knowledge or advice? Dean
B
Your assertion that polyiso is susceptible to a massive R-value reduction is PATENTLY FALSE in a wall assembly. The study you are referring to is based on MEAN temperature. So, as you state, polyiso will be reduced by 25% to R-4.9/inch (still better than mineral wool, cellulose or fiberglass). That said, in order to get the wall cavity to the temperature required to have this reduction, (which is NOT 50°F, rather closer to 20°F) you would need an interior conditioned space of 70°F and an exterior temp of -30°F!
You really should either revise this post of just remove it completely as it is absolutely incorrect. Not to mention that it has been shown through use of thermal modeling that 2.5" (R-15.9) of Polyiso up to Climate zone 6, will exceed code standards based on U-factor performance. That doesn't sound like low temperatures have anywhere close to the impact you implicate.
One thing I didn't see addressed in your article is the effect of age on R-value. This article says polyisocyanurate loses 75% of its r value in 5 years, and nearly that loss in about two years according to the graph they included. Having decades of experience with our own cold storage warehouse insulated with spray foam polyurethane, this sounds extremely exaggerated and inaccurate. Thoughts?
Thanks Mike for your reply. I either forgot to include the link to the article or your website does not allow it. Just in case I'll post it here again. The graph I referenced is on page 3 of the PDF.
B
Hi Mike, I could use some guidance on a building situation that we have created. We needed extra storage for our furniture and belongings while embarking on a large house renovation. We have a large old dairy barn. So we built a large “box”/room in the middle of the barn to serve as a storage unit. We used plywood to construct the box, installed 2 windows and conditioned the space with a mini split. Next we installed XPS on the interior walls. Our plan was to leave the walls as is after this. However, after doing some research and reading on this site, I am now concerned with the off gassing that is occurring. Fortunately, we are not living in the space but I am concerned about our furniture absorbing the off gassed chemicals. The room is supposed to be “temporary” so we did not plan on putting drywall up. I was considering covering the XPS with plastic but did not want to cause a moisture issue. Do you have any suggestions? Thanks!
Hey Mike Great article I learned a lot but still not sure which product to use. My project is a small scale dehydration lumber kiln, max operating temp 160 deg. It is 2x4 construction with one 2" layer of foam board between the studs and another 2" foam board attached to the studs on the inside. It is then covered with 6 mil plastic and 1/2" cdx plywood and all joints taped and sealed and interior painted with alminum roof coating. Every attempt is made to keep water infiltration out or to a minimum however in a kiln moisture will eventually get into the walls. The two options I'm looking at are the Foil faced EPS or the Polyiso. Before researching the differences I purchased The EPS and am now having second thoughts. I could use this on another project if I had to but because of the price would really like to use it on the Kiln. My main concern is temperature will EPS have a problem at 160 deg.? Will the EPS become water logged over time? Other forums that deal with Kilns recommend using the Polyiso, but after reading your article if temp. is not a problem I'm thinking the ESP should work just fine. Hope I'm right but I have been wrong once before in my life.
Thanks for the excellent article.
I learned a lot... . Much appreciated.
2 questions I have -
If PIR r value drops 30% in cold temperatures, doesn't it still match or outperform it's competition in r value?
30% of 6 =1.8
So remainy r value = 4.2
A little higher for 6.5 foam.
Just wondering.
Second, I have been driven nuts by the itchy feeling from every insulation I've installed other than the blue recycle denim/cotton stuff.
Are either xps or eps irritant free? I have not tried them yet.
Thanks
M
Hello.
Thank You for interesting read.
First time i hear about this loss of insulating properties of PIR boards at low temperatures. Extremly usefull information. In the paragraph You have mentioned a December Chicago study - and refered us to "see below".
Could You please refer me to this study?
Thank You in advance
Cheers
Maciej
Hi ! Enjoyed your article but now more confused on what insulation would be best for my home. I have an farmhouse and am renovating the bedroom first floor ceiling. We took down the drop ceiling and want to refinish the ceiling and expose the beams. What type insulation is good for low off gassing and sound proofing and R value? The 2nd floor above is not heated. We were thinking using rigid insulation and then cover with Armstrong wood planks leaving beams exposed. We are concerned with VOCs, want to be green as possible and have good fire retardant and moisture prevention. Can you help with our insulation choice? Rigid would be easiest to install. Thanks!
Dawn
Z
check out Rockboard 40/60, 60 & 80
Thanks for this informative article. We are looking to reduce heat loss in our unfinished basement (s house) and considering having HFO sprayed directly onto the thick concrete basement walls. I am concerend about some of the cons of using spray foam. I was considering rockwool comfortboard (attached directly to the concrete walls) as an alternative, but not sure whether this could lead to moisture problems with moisture leaking through the concrete walls and being retained by the comfortboard. Should we use a poly moisture barrier between the concrete and comfortboard? We can get moisture in the spring and summer when humidity is high and run a dehumidifier during this time. We are not planning to frame the walls at all, so didn't want to combine with framing and batts. Would this be a viable alternative to using spray foam in this sitution? Would faced EPS be a better alternative that comfortboard? Thanks for any advice you can provide.
W
I need info on which insulation board for inside unfinished basement to protect from radon.
W
Hi Mike, foamular is said to be a protection from radon. I've read a LOT about radon. Short of having a radon mitigation system installed, we're trying other ways.
House was built in . basement has fiberglass batting on walls, no studs, no framing on walls. We've used radon sealer on floor. It's dropped the radon from around 4.75 to around 3. We're going to be doing the walls next with the sealer. [it's just a lot of work for 2 older people] The basement is unfinished. Walls and floor are concrete. We ran a dehumidifier last summer, have only been here for one year. Had to empty quite regularly. so there is humidity down there. There is no moisture problem thru the walls, even though 3 walls have earth around them. it's a walkout basement. The east facing door and window are not framed in, eg not finished.
We're in virginia, temps don't usually get down to -10F in the winter. They can and have, but not every winter.
If you want to learn more, please visit our website XPS board manufacturing line.
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