How does TechShield® compare to AtticFoil®? I get this question just about everyday. First, what is Techshield®? Techshield® is a roof decking material – usually OSB that has a sheet of aluminum foil laminated on one side. Techshield® is made by LP Building Products or Louisianna-Pacific Corporation and is probably the most popular brand of radiant barrier decking. Other brands are Solarboard by Norbord and Thermostat by Georgia-Pacific.
The main difference between Techshield® and AtticFoil® is that Techshield® is used almost exclusively for new construction or whenever a roof deck is being replaced. AtticFoil® is most commonly used inside the attic of existing homes.
For most new construction projects, I recommend using TechShield® (or another brand). The products work well, the cost of upgrading from regular OSB decking to radiant barrier decking is pretty minimal and there is NO additional labor cost since the Techshield® is installed just like a regular OSB roof deck. The foil side MUST face the attic air space (foil facing DOWN). If you install the foil facing up and then put roofing felt and shingles on top, you will get NO benefit.
Do they work the same? Yes and No. Techshield® works off a quality called EMISSIVITY. Basically, this is the ability to NOT convert energy to radiant heat. The roof deck will get hot and would normally want to emit radiant heat both upward and downward. By putting the foil on the bottom of the roof deck, it greatly reduces the ability of the deck to radiant heat downward. This is similar to taking two HOT baked potatoes and wrapping ONE with foil. The potato with foil will stay hot longer since the foil will reduce or slow down the amount of energy (heat) emitted.
If you were to wrap only half the hot potato with foil, then you have something similar to TechShield®. In this case, the potato would emit more heat upward through the area without foil compared to the side with foil. By reducing the heat emitted into the attic, this causes the attic contents (wood, insulation, framing) to be cooler. Combined with adequate attic ventilation the attic air temperature will also be significantly cooler.
AtticFoil Radiant Barrier draped under a new roof deck.AtticFoil® works off the quality of REFLECTIVITY since there is an airspace between the source of heat (the roof deck) and the foil. The radiant heat is STILL emitted by the roof deck, but hits the foil and is reflected back keeping everything below the foil cooler since the items never get a chance to absorb the radiant heat coming off the roof.
Don’t worry about overheating the roof deck – it will only increase between 2º-10º degrees.
By stapling to the bottom of the rafters, you will usually achieve a greater reduction in overall BTU’s coming into the attic compared to radaint barrier decking.
Can I make my own radiant barrier decking like TechShield using AtticFoil®? You can and it is VERY easy!
Simply roll AtticFoil® Radiant Barrier foil out on standard 4’x8’ sheets of OSB or plywood. Then use a hammer staple and ¼” staples to tack it down. When installed over the rafters it will jut like a piece of radiant barrier decking. Or, if you want to install a radiant barrier for new construction, you can run the foil across the rafters and let it “droop” down about 4-5” between the rafters. By doing this method, the AtticFoil® will work off the reflectivity quality compared to the emissivity quality of foil. Be sure to leave a gap at the top and bottom of each rafter run for air to find its way up and out of the attic.
Very informative and exactly the verification that Iwas looking for. Our area in Dallas was recently hit by a hail storm and we have to install a new roof. I was looking to incorporate some form of radiant barrier since i have this opportunity. After reading your information it appears i have no opportunity to improve the situtation unless i have missed something or you have another suggestion.
Thanks
Mike
Mike,
You are correct in that you are pretty limited if you want to just scrap off the old shingles, and put new shingles down. You MUST create some type of an air space to force the heat to convert to it’s radiant form. Then, when the heat tries to cross the airspace, it can easily be reflected.
Here are some options for doing this. You can Install Radiant Barrier Under a Metal or Tile Roof. Or, take a look at what I did with my home. I built a double-deck roof system and used traditional shingles, but the air space is between the two decks.
All The Best!
Ed
Can I run the foil across the rafters and let it “droop” down about 4-5” between the rafters, then lay techfield roof deck on top.. would that work as well as the double deck system??
Pilar,
Combining a radiant barrier decking with the “drooped” method will definitely yield better results than the radiant barrier decking alone. I would not say it will perform the same as the double deck system since that system is installed over a foam-sealed non-vented attic. I used to not really recommend adding AtticFoil Radiant Barrier below Techshield since I did not think it would produce a substantially result. However, from personal experience with the double deck system and hearing from many customers who have installed in an attic under Techshield, I now think that if you can keep the cost down (A DIY installation) then it is worth it.
Hi Ed
I have a question about a metal roof. I was reading about air flow. I’m redoing a sun room that has a flat metal (tin) roof on it. I am planning on running 2 x 8’s and then installation inbetween the rafters and then OSB techshield on top. I will not have any air flow because it’s a flat roof. So I see you need air flow for it to work. My question is would it help for me to install the techshield with no air flow or would it make it hotter ? Also should you use techshield on outside walls ? I live in so. CA so it gets very very hot here in the summer. Thank You, Jim
Jim,
Just to clarify: it’s not air FLOW that is needed for the foil to work, it is an air GAP that is required (meaning the air can be a dead air space, and not flowing/moving). With no air gap, the heat will not be in radiant form so the Techshield will be useless as a radiant barrier. Take a look at this page for more info on why the air gap is needed for any radiant barrier to work: Why An Airspace is Required for Radiant Barrier.
You can use radiant barrier in walls – again, you just have to create an air gap. This page details exactly how to do this: Installing Radiant Barrier in Exterior Walls.
Ed,
Great to see your pages and good to know the owner of AtticFoil. I bought 1000 SF of your 26 inch wide foil and put up about 500 SF in the attic of my 2800 SF 2 story. I posted a video of it when I measured the bottom of the east facing roof at 11 AM last July. It was 102 degrees. After your atticfoil went up the underside was 85 degrees, the temp of the air we were in.
I am convinced that the roof heats the air and the air heats my ceiling and the ceiling heats my rooms. Do you know of any scientific study that corroborates my theory? I am sure that it almost does not matter how much insulation I have, the ceiling will heat up.
Kurt,
You are on the right track as far as the direction of the heat flow, but it’s not so much the hot AIR that is causing uncomfortable living spaces, it’s the heat traveling THROUGH the air (the radiant heat flow) that is getting absorbed into the insulation and, ultimately, the home. So it does in fact matter how much insulation you have because a small amount of radiant heat will pass the foil and it will travel until it is absorbed into the insulation. Having that insulation between the heat source and the living space slows down the conductive heat so the home doesn’t heat up as quickly. Otherwise, if it were all about air temps, then ventilation should be able to cool a home, but we know that ventilation alone does not in fact do that. A more in depth look at this can be found here: Radiant Heat vs. Conductive Heat
I am not clear. You recommend TechShield, but then at the end you talk about AtticFoil. AtticFoil’s reflectivity, the way I understand you, sounds more efficient. Is that the case?
Thanks
Yes, technically it’s been shown that radiant barrier using REFLECTIVITY (like AtticFoil) has a greater impact at reducing the delta T versus a radiant barrier using EMISSIVITY (like TechShield). More info here: Emissivity vs Reflectivity in Radiant Barrier Foil
I bought a shed and it has tech shield facing into the shed.. Can I use fiberglass insulation with a foil barrier to finish the walls and then plywood… Thank so!!
No, this will NOT work! The foil requires an air space in order to work, so you can’t sandwich the foil on the Techshield by placing insulation on top of it and even it that insulation had foil, covering it with plywood would sandwich that layer. No air gap = no radiant heat & radiant barrier is useless. If you want to add insulation to the walls, you’re gonna need to get an air space in between the foil face on the Techshield and the new insulation.
Hi Ed,
To this point, I have a newer home with the LP Techshield installed in my entire house and I still have rooms—directly impacted by the attic—that are either too hot in the summer or too cold in the winter.
I was looking at installing a reflective insulation in my attic (with the air space between the TechShield and the next layer of insulation. Is it overkill or with this help the attic space not heat up my blown in insulation (that seems to just trap heat even with TechShield) on the floor of my attic—which directly impacts the temperature in the rooms with the temperature issues.
Just trying to make my home as efficient as possible; however I don’t want to pend money on an improvement that won’t be worth the investment of time or money.
Thanks so much!!
We have many customers who have the time and energy to add a layer of AtticFoil along the bottom of the rafters and they have seen good results. It’s fair to expect the Techshield is working to some degree, but it’s only working where it is (in between the rafters). The two won’t interfere with one another and there are no concerns with using both in the same attic space.
Hello,
We just bought a shed and are converting to a tiny home. It came with LP tech shield on the ceiling between the rafters and its all open. In a small space does it need any more ceiling insulation? We want to leave the rafters open and exposed, is there any specific material we can use to make an decent ceiling between the rafters w/o affecting the tech shield? Or do we just make sure there is space between the material and tech shield?
Thanks in advance!!
Hi Kelly, congrats on the new home! So yes, if you plan on keeping this space comfortable year-round since you’re living in it, you need some R-value in addition to the radiant barrier decking. Unfortunately there’s no *product* that exists that allows you to do this AND also keep the rafters exposed; this can be done during NEW construction or by renovating the whole roofline, but nothing to just throw up there to give you value. My advice would be to add a baffle vent (or some foam spacer blocks) and then add some rigid foam board into the cavities. Try to get as much thickness as you can fit in the space you have, so you maximize your r-value up there. Then, cover the foam board up with some other interior finish material, whatever look you’re going for. Good luck!
Hello,
We have old roof from 1929 that has 1×6 boards over the trusses, then many layers of shingles. When we install new shingles should we put the radiant plywood over the 1×6 boards after removing shingles? If we do there would not be any air flow to the foil side of the plywood. Is there a better way to do this? Thank you!
jeff
I’m assuming that there are NO spaces/gaps between the 1×6 boards. If this is true, then applying radiant barrier decking directly on top will give you NO radiant barrier. You MUST have an airspace for it work: Why Is An Airspace Required For Radiant Barrier To Work? If there are some gaps between the 1×6 boards (say 50% open) then you would get a 50% benefit.
Im in the same boat as Chuck Manion comment from December 30, 2015 at 5:43 am. Just got my new Tuff Shed delivered but it also has the siding with the integrated radiant barrier facing inside the shed. My goal was to use foam board insulation in the walls that also has a radiant barrier on it, then sheet rock it. Since they both hace radiant barriers can they touch, I have read in one place that you could cut small strips of foam board to put under the foam board to create a small gap between the wall and the foam board. Would this work?
This is my home office and it is way to hot inside with the existing siding.
Thank for any advice.
Bo
NO, the radiant barrier surface must remain open to an air gap of at least 3/4″ in order for there to be any radiant barrier benefit. If you touch the foil in the cavity to the foil on the foam, you’ve simply created a conductor for heat to travel through those layers. If you could get the foam board in the walls without it touching the other foil layer (using spacers or just measuring and precision with installing) then you would have working radiant barriers to help you keep that shed comfortable year round.
I am new to roofing and have a question. If there is foil OSB on the roof deck, is there any special ventilation requirements? (ridge vent, power fans, gable vents). I have read where the foil osb reflects the heat back onto the roof deck, thereby possibly causing the shingles to have a shorter life expectancy.
There is no special/specific type of venting required when using radiant barrier OSB. You can go with any of those that you mentioned, but in general I recommend passive ventilation in an attic. To learn why I have this stance, you can read more here: Basic Attic Ventilation Tips
If the normal method for a metal roof is to put down plywood or OSB over the rafters, then put down a radiant barrier foil, then purlins (to provide the air gap), then the metal roof, wouldn’t it be similar when using a techshield like product? Techshield with FOIL FACING UP, then purlins (to provide air gap), then metal roof? If not, why?
In theory, yes this would work as far as reflectivity. However you would loose the benefit of having a secondary drainage plane. Putting the roll foil under the metal will keep any liquid water from getting into the decking. This can happen when the surfaces are below the dew point. Just like leaves on a tree, you could get dew or condensation under the metal roof. If there was enough, it could drip down through the gaps in the decking or be absorbed by the decking and swell. You have the right idea, I just don’t think it is worth the risk of giving up the secondary waterproofing layer.
Thanks!
Hello all,
We have Techshield in our attic when we bought our house and we got hit with hail and got the roof replaced. When they put in the new roof, the techshield were punctured all over. We talked to the roofing company and they said it shouldn’t matter. Fast forward a year later and our electricity bill is consistently 15 – 20% higher compared to previous year prior to the roof being replaced. My question is will the techshield still works the same with these holes from the roofing nails or does it need to be replaced?
I truly appreciate your time.
Cyn
Some holes in the foil should not have that much of an impact on your electric bill. I think there must be something else going on. Did you change to a darker roof, did the ventilation change? The AC unit could have an issue, could be hotter this year, etc. The amount of benefit for the radiant barrier osb is directly related to coverage. If 10% of the foil is knocked off then it would reduce benefit by 10%. However, this would barely affect your bill.
I’m enjoying reading through this great information. I too have another Tuff Shed question. I’m in south Louisiana so I need to help lower the interior temp of the shed as much as possible. The model I’ll be purchasing uses LP SilverTech Radiant Barrier on the roof deck and walls. The previous comments about using foil in the Tuff Shed in addition to the radiant barrier both seemed to be a situation that would eliminate the air gap. If I used Attic Foil or foil foam board and tacked it to the 2×4 where one would normally install sheet rock I’d keep the air gap. Being that I’m trying to keep the thing cool as possible would doing this be beneficial?
Thanks in advance,
Scott
Scott,
If you staple/attach radiant barrier foil below the rafters and the Techshield, it will reflect any heat coming off the Techshield and it will also stop the rafter ends (that are not covered in Techshield) from emitting heat downward. Overall the Techshield is probably doing a decent (not quite as effective as the staple up foil would do but still pretty good) job at keeping the majority of the radiant heat out but adding another layer to address the thermal bypass on the rafters ends and get some r-value up there (via the foam) isn’t a bad idea. Remember to keep your expectations realistic – the air should be within 10-12 degrees of outside air temp on a non-conditioned shed. So on a 96F day, the inside shouldn’t be more than 106-108F. If you have good ventilation, the shed will be more likely to be closer to 96F.
If you really wanted to cool it off, then you could add the foil + more r-value, seal it up and then condition it, but that may be beyond what your intended use is for.
Can Tec Shield be painted? Can Tec shield Be cleaned? these questions are fire related Soot and the like. Insurance adjuster claims it may be cleaned or painted rather than replaced. Please advise.
No, it can not be painted. If you cover the foil side in any way, with any material, you’ll eliminate the air gap that is required for it to work! Techshield must have its foil surface open and exposed to air only.
On the flip side, yes, you can clean it (though it’s probably not necessary). Just use a dry or slightly damp (with water) rag/sponge to wipe it clean; I would not suggest actually wetting the surface or using heavy cleaners on it.
I have a Wolf valley shed that will be turned into a tiny house. My ceiling has LP shield in place 2×6 rafter, can I insulate on top with r13 or r15 then drywall and the LP shield still work? Thanks
Nope, if you cover (or push another item up against) the foil surface on the decking, it will not work as a radiant barrier. You must find an option that allows you to maintain an air space of at least 3/4″ on the foil surface.
Can I install this in my attic inside the house?
Absolutely! Find the install info here: How to Install AtticFoil in your Attic
Instead of tacking the foil to OSB can I just lay it flat along the rafters then put OSB on top? Without the draping that you mention, would this not work like the emmisivity principle that you mentioned? Thank you!
Frank – yes, exactly. The reason I like the draping method is because reflectivity is slightly more effective AND the draping allows for some back ventilation between the deck and the foil to usher that heat out the exhaust. Not mandatory, but it’s a nice option to have!
Thanks! Since this is a new build would you say that on top of the rafters with draping or under the rafters would be more effective? Thank you!
Good question. Stapling below the rafters is best and a little more effective than draping over the rafters. However, draping over the tops of the rafters is much easier.
I have a tuff shed with lp radiant barrier roof, techshield. Its a tall pro franch tuff shed. Can i lay insulation on top of the ceiling panels will be attached to the bottom rafters inside the ceiling and since it want be touching the lp panels?
No, if you have materials touching the foil surface of the Techshield material, the foil can’t block heat like it is supposed to. You would have to find a way to maintain at least a ½” to ¾” gap BETWEEN the foil side and the insulation you want to add.
Please tell me I’m assuming correctly after reading all these comments!
I recently purchased a shed, that I will be using as a workshop, that tech shield ceilings and walls.
If I use foil faced board between studs to help insulate, both ceiling and walls, if I leave an inch of air gap, have the foil facing inside and do not drywall.
Thank you!
Eric, as long as the foil surfaces do not touch anything (just face an air space of ½” or more), you’re good to go!
I have an old hunting cabin that has a double roof. The first roof was corrugated aluminum then a layer of insulation was placed over it and another aluminum roof then applied. It is time to replace and improve the look so I am thinking of pulling the old roof off and framing a new roof above that will include over hangs. It sounds crazy to frame over and existing frame but this structure was so lightly built to begin with and I’m short on time to pull everything apart. So putting a light frame over it seems to be the easiest and fastest solution. The sandwiched layer of insulation worked well over the last 40 years so the plan is to leave it as is and just pull off the top roof sheet. Since I have it separated and the top of the sandwich exposing insulation would a radiant barrier such as Starfoil double bubble double sided 5/16 foil produce any better results if I loosely lay it on top of the insulation and tape seal it to keep if from blowing while framing or attach to top side of widely spaced rafters. The plan is to place rafters 48″ OC and connect them with 1×4 spaced above for some rigidity as well as a nailer for the 5-v roof. Thoughts? Thank you.
If you plan to add a foil radiant barrier on top of a roof, you should consider installing RoofingFoil™ + Underlayment All-in-One. It’s a vapor barrier that’s rip-proof and provides an excellent shield against radiant heat flow. You’d just lay if over your existing insulation, then fur it out at least ½” and then put your new metal roofing on top. More installation info here: How to Install RoofingFoil Under a Metal Roof
My home was built with LP TechSheild, and a traditional ventilated attic with mechanicals including a NG (on demand) hot water heater and furnace.
What is the best way to move to a sealed attic (using spray foam under the roof deck)?
Is there a product, or mix of products, you could recommend that would allow me to retain an air gap for the LP TechSheild and seal the attic?
Yes, you could add RoofingFoil™ + Underlayment to the inside of the rafter cavities (leaving a gap between that and the bottom of the deck) with the foil side facing the decking and then spray foam to the bottom of the RoofingFoil™. Feel free to email me for photos and more details – you can email through the RoofingFoil.com Contact Form.
Would there be value in attaching attic foil to back-side of radiant barrier (opposite foil-side), then attach the barrier to the underside of the roof rafters? Would the attic foil act on reflectivity and under-side of the barrier act on the emissivity?
We have many customers who have the time and energy to add a layer of AtticFoil along the bottom of the rafters and they have seen good results. It’s fair to expect the Techshield is working to some degree, but it’s only working where it is (in between the rafters). The two won’t interfere with one another and there are no concerns with using both in the same attic space.