As I talk about on the AtticFoil® site, adding a radiant barrier inside your attic can usually REDUCE the possibility of ice damming.
Ice damming is caused when the top of the roof warms above the freezing point the the lower part of the roof is below freezing. When this happens, the icy roof water melts and that water trickles down and refreezes at the edge of the roof where it’s cold. The roof gets warm due to warm air leakage into the attic from the home or from duct work inside the attic space.The roof can also warm up if the sun comes out that day. A roof with snow can get hit by the sunlight, which warms up the roof and begins the melting process. By the time the sun sets, and the temps drop again, that watery edge can re-freeze, creating ice dams and icicles.
The Key to preventing ice dams
To prevent ice damming, you want a COLD roof. The roof gets warm due to warm air leakage into the attic AND from the home emitting radiant heat. A radiant barrier will help keep the radiant heat emitting from the home from hitting the roof. The result is a COLDER roof deck which will reduce ice damming. Many customers have seen a significant reduction in ice damming after installing AtticFoil radiant barrier. I would also suggest checking to make sure you have good attic ventilation. Cold air entering the attic will also help keep the roof COLD.
Fix Ice dams now!
Now you know what ice dams are and how to prevent them, but what if you’re dealing with them right now? Not to worry, I have some tips that can help you fix the problem and keep ice dams at bay.
Ventilation
Ventilation helps your attic stay cool by funneling cold air from outside through the attic space and out somewhere near the upper third of the roofline. Ventilation keeps the air temp in the attic cold, and it helps dry up condensation or moisture.
Air Sealing
Air can easily leak out of ceiling penetrations (think ceiling fans, can/recessed lighting, vents, etc.) and into the attic space. Make a plan to go up into the attic, revel these areas and then work to seal them up. A small can of spray foam can go a long way toward sealing up cracks and spaces in these areas.
Radiant Barrier
Many customers have seen a significant reduction in ice damming after installing AtticFoil™ radiant barrier. Whether you’re stapling the foil up on the rafters or using the SuperPerf™ that was designed to go on top of the attic insulation on the attic floor in cold climates, you’re helping keep heat in the house and off the roofline.
For an attic with ductwork or HVAC/furnace equipment in the attic, a staple-up method is your best bet. Staple the foil up everywhere under the rafters. If you live in a mixed climate and would also like the benefit of helping keep the heat in during the cold months, go ahead and do a second layer of foil by adding SuperPerf™ on the floor over your insulation everywhere else. If your attic is empty of ducts or HVAC stuff, then you can just do the one layer of SuperPerf™ on the floor. Click here to see how to install AtticFoil ™ SuperPerf™ for cold or mixed climates.
Final Thoughts
Ice dams happen because your roof temps fluctuate between warm and cold. If you can keep your roof deck constant and equal to ambient (outside) air temperatures, you can greatly reduce the chance of ice dams forming on your roofline. The easiest way to do this is by adding a radiant barrier in the attic space. If you want to do more, consider checking for proper attic ventilation and well-sealed ductwork. All of these combined will help you eliminate the problem of ice dams forming on your home.
Tags: Attic Insulation, cold climates, freeze, ice dams, radiant barrier
There’s a lot of misinformation about attic ventilation, so we wanted to take a moment to clear up any confusion about how you should be venting an attic and what you need to do it right.
1. If I have roof vents, I have ventilation.
If only it were that simple! Attic ventilation should have a balanced amount of both air coming in to the attic and air exiting the attic. (It’s ok if you have a little more air coming in than you do going out. For example, lots of soffit venting.) The main way air enters attics is via soffit venting. These vents allow cool, dry air to enter the attic at its lowest point and as air travels up and out the higher points (ridge, turbine, gables) so that the airflow removes warm, moist air from inside the attic. For exhaust you can have a ridge vent, a static roof vent, a turbine (whirly bird) vent or gable vents. Some people have powered attic fans or solar fans, and those are ok too. Just beware of mixing passive and active venting in an attic – that’s a bad idea!
2. More ventilation is always better.
Too much of a good thing can be a bad thing. I recommend you choose one type of exhaust vent and go with it. Ventilation is simple because air always travels the path of least resistance. When you mix exhaust vents on a roofline, the strongest vent will overpower any passive venting and then pull air in from any nearby exhaust vents! This disrupts the normal path of of air coming in the bottom and out the top and defeats the whole purpose of having low/high vents.
So while it’s generally a great idea to have plenty of soffit vents for intake, having too many exhaust vents or mixing exhaust vents can counteract your goal of cooling the attic air temperature.
3. The best way to get air moving in an attic is by using powered vents.
This idea flows from the one above and I’d just like to reiterate that a passive ventilation system will work just as well (and for free) as a powered (active) ventilation system. You’ve heard me say that I don’t typically recommend the use of any sort of powered fans and the top reasons why I feel that way, besides that they work just as well as passive vents, is because of 1) cost, 2) noise, and 3) some only work on sunny days!
Many people may not realize that it’s usually fairly breezy at the top of a roof. Standing down on ground level, you’re blocked by fencing, homes, etc but up top without obstructions, there’s a good amount of air flow. Just a little breeze moving can turn wind turbines and allow them to effortlessly pull out as much air as an electric fan can.
What if you already have fans? Not to worry! Again, fans work and won’t be a problem as long as you feed the fans with plenty of intake air. So take some time and check on your soffit vents. If they’re not cut out, get them cut out. If they’re blocked, clear the path and maybe install some baffle vents. If they’re dirty, clean them! Dirty soffit vents are actually the leading cause of attic ventilation problems and so much so that I made a video to help show you how you can clean them yourself and get things back on track with airflow in the attic.
Don’t neglect giving the fans a source of intake because without it, the air in your attic will depressurize and it’s likely going to result in air from inside your home getting pulled into the attic space via light fixtures or other ceiling penetrations. The net result is that your home feels warmer faster, and your air conditioner has work harder than ever just to try to keep things comfortable (ie. huge energy waster!).
Want more myths debunked?
Tags: Attic Ventilation, gable vents, powered attic fans, ridge vent, roof venting, roofing, soffit vents, solar attic fan, ventilation
Introducing our exclusive new radiant barrier tape and white tape from AtticFoil®!
This image is watermarked, actual products do not have any markings/stamps on them.
Do you have a project that needs a patch job? Maybe an attic installation where you are joining together two large pieces? Do you want to put foil up in your metal shed easily? Then our new AtticFoil® tapes might be what you’re looking for! Air conditioning professionals, general contractors, and handymen will love this tape too because it’s as strong as it gets.
Our tapes are just as strong as our foil products – they’re virtually impossible to tear! The rolls are 2 inches wide and run 164 feet in length. You can choose from a classic foil tape or a clean white finish tape. Both styles coordinate with our 2 best selling styles: Original AtticFoil® and AtticFoil® + White.
Simply unroll the length you need, cut it off the roll with scissors and peel off the backing to reveal the adhesive side. This adhesive is super strong and will stand up over time to heat, wind, and other normal circumstances.
To find out more information about our tapes, or any of our other radiant barrier products, check out our products page on AtticFoil.com.
Original AtticFoil® is an amazing product – it blocks over 97% of radiant heat, it’s tear-proof and it is heavyweight and easy to use. Many of our customers install the foil by stapling it up under the roof rafters, creating a sort of ceiling. This is most common in Souther states where air conditioning ductwork is typically installed in the attic. This method is great for reducing radiant heat gain into the attic in hot climates.
However, we also have many customers in cold or mixed climates that were looking for benefits from our foil both in the hot summer and the cold winter. The solution to a climate zone like this is to lay the foil on top of the insulation (as long as the attic space doesn’t have any HVAC components or tons of storage, otherwise a hybrid method would be best). The over-insulation install method allows the foil to still block radiant heat coming off the roof in the hot months but it also keeps the insulation warm in the cold months, making the home stay more comfortable and energy efficient.
Although the original AtticFoil® does a great job of allowing moisture to pass through its micro-perforations, there are some circumstances where the moisture level could be exceptionally high and water could get trapped. Keep in mind that this is a rare occurrence; however, the FEAR of trapping moisture has caused many people to be hesitant about installing a radiant barrier directly over their insulation in cold or mixed climates. SuperPerf™ is a customer driven product; we had many customers tell us, “I want to install a radiant barrier, but how will I KNOW it won’t trap moisture?” Unfortunately, every home and circumstance is different and we just couldn’t make that promise with our original product.
With that in mind, we developed an exclusive foil barrier product that not only offers the same reflectivity (97%) as our original foil, but it also offers the added peace of mind of not trapping moisture. We call this product SuperPerf™ because it has larger perforations than our original.
Whereas the original AtticFoil® is micro-perforated (done with tiny pin-holes – seen on the left of this photo), the SuperPerf™ is punch-perforated, meaning an actual piece of the foil (quite small) is punched out and removed (seen on the right side of the photo). This is just like the idea of using a tiny hole-punch on a piece of paper. The result is an extremely breathable radiant barrier foil that still offers you great coverage and protection from radiant heat gain/loss.
If moisture concerns were keeping you from looking more seriously in to adding a radiant barrier on top of your existing attic insulation, I encourage you to give the new SuperPerf™ a try. I’m confident you’ll feel good about using a product that was specifically designed with cold climates in mind by a trusted leader in the radiant barrier industry. If you have any questions about the new SuperPerf™ or if you’d like to get your hands on a sample of it, feel free to contact us or request our sample packet online.
If you have a special application or project in mind and want some advice on how to incorporate a radiant barrier – send me an email! Until then, stay comfortable out there…
Q: Can I install radiant barrier if I have spray foam up on the rafters of my attic? How does AtticFoil work with spray foam?
We get this question a lot – someone is usually in the process of new construction and they want to incorporate both the AtticFoil radiant barrier AND some spray foam in their attic space. First, I’d like to say that the two products compliment one another very nicely. Foam isn’t going to perform like radiant barrier because (like traditional insulation) foam slows conductive heat gain/loss, but it doesn’t actually stop it. Radiant barrier foil is different than spray foam because AtticFoil’s reflectivity of radiant heat is 97%, meaning you stop the heat from ever even entering the home.
That being said, The foil is most effective at this when it’s closest to the outside layer of the home. For this reason, adding the foil with the required air gap it uses, can be tricky. There are several ways to go about this. First, you could use a traditional Cathedral Ceiling Method for Installing Radiant Barrier. In that case, you’d have some spacers added to the bottom of the roof deck, then the foil, then an intermediate layer like foam board, then spray foam over the foam board. The reason for the intermediate layer is because in many cases, the spray foam does not attach well directly to the pure aluminum radiant barrier.
Another, more economical option, is seen in this scenario pictured below:
The roof decking is being laid on (or replaced) and you can clearly see that the foam in between each rafter cavity leaves a small air gap between the foam and the deck itself. AtticFoil radiant barrier only requires a 1/2 to 3/4″ air space in order to work effectively; in this situation, you could run the foil across the top of the rafters and staple it down before new decking way laid on top. Another option would be to attach the foil directly to the bottom of the decking (or use a pre-manufactured radiant barrier decking) and then lay the decking down, with the foil facing the small air gaps. This is a perfect example of using radiant barrier and spay foam together and this is an ideal installation because the foil will serve as the first line of defense, reflecting 97% of the sun’s radiant heat from entering the layers below the foil and then the little bit of heat passing through the foil will covert to conductive heat and the spay foam will significantly slow down the transfer of the conductive heat into the attic and/or home as your second line of defense.
Q: What about adding the foil from the inside, below the rafters filled with spray foam?
For blocking heat (ie. summertime benefit) the foil is not going to offer much benefit being placed that far inside the envelope. There might be some benefit for heat retention in winter, since the foil would be right near the heat leaving the interior of the home, but generally people are adding foil to roofs/attics with spray foam because they are trying to lighten the heat load in the summer, even if they also want the benefit of keeping heat in during the winter.
Bottom line: for a situation where you want to stop heat gain and/or you are looking for year-round benefit from the radiant barrier foil, it’s best to place the foil closest to the exterior of the home/building.
I’ve talked about attic ventilation issues before, in fact it’s probably one of the most popular posts on the blog to date. In that article I touch on this issue and in this video I decided to go a little more in depth based on the frequency this problem comes up in conversations.
https://www.youtube.com/watch?v=NUvgeP7–0Q
What do you think? Is this a problem you’ve personally experienced in your attic? Did you have situations like the examples in the video? Tell me about it in the comments!
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With the increasing interest of radiant barrier in commercial applications, and the amazing results from installing it in non-conditioned and conditioned spaces, it was only a matter of time before we would need to have a separate space online for these applications. Thus, WareHouseFoil.com was born!
WareHouseFoil.com is a site that is 100% dedicated to non-residential applications for radiant barrier foil. Unlike AtticFoil.com where we address residential installs, WareHouseFoil.com focuses on metal buildings, wood sheds, barns, commercial warehouses, airplane hangars, and any other structure used for commercial purposes. The site features photos, installation instructions and tips as well as videos. If you have a commercial application that you are considering using radiant barrier for to address heat gain/heat retention, start by visiting www.WareHouseFoil.com, if you still have questions, we’re always a phone call or email away.
Tags: commercial, metal buildings, radiant barrier, radiant barrier foil, warehouse
