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Alternative Roofing Attachment Methods: Carlisle Roofing Series #3
You don’t always need a bucket of adhesives to attach a single-ply roof. In the third installment of the Carlisle Roofing Series, we explore two alternative methods—RapidLock hook and loop attachment and VacuSeal wind-vented attachment.
Carlisle’s Chad Buhrman, insulation product manager, and Alex Drescher, VacuSeal product manager, walk editor-in-chief Janelle Penny through the options.
*This podcast was created in partnership with Carlisle SynTec Systems.
Missed the first two? Listen here:
Rather read the transcript? See it below:
Janelle Penny: Hi, this is Janelle Penny, editor-in-chief of Buildings magazine and today we’re going to talk about two specific alternative attachment methods for single ply roofing: the RapidLock hook and loop attachment method and the VacuSeal wind-vented attachment method.
We’ll have two speakers for this podcast today—Chad Buhrman, insulation product manager, and Alex Drescher, VacuSeal product manager for Carlisle. Welcome guys.
Chad Buhrman: Thanks for having us.
Alex Drescher: Thank you.
Janelle: So, being in product management, a main responsibility of your job is new product development. What do you see as some new innovations or trends that you’re noticing in the roofing industry?
Chad: Thanks, Janelle. What we’re seeing are a lot of the new products in commercial roofing currently are focused on what we would call labor savings to the contractors, so, trying to be able to get through the project and get off the roof as quick as possible.
It’s probably no mystery to your publication that the available labor pool for commercial roof installs has been dwindling. And a lot of the folks that have that knowledge and experience are aging out of the industry. We’re not getting a large influx of young folks coming into the industry as contractors.
So, we’re constantly looking for methods in which we can put roofs down simply, consistently and quickly.
In addition, we’re also seeing some of the environmental regulations come into play like VOCs or Volatile Organic Compounds and having limits on those in certain jurisdictions.
So, a lot of our product development is focused on just making those products easier to install, quicker to install, repeatably consistent, and also compliant with VOC and other environmental standards that may be out there.
Janelle: Great. So, let’s start with RapidLock technology. Can you explain a little bit about what that is?
Chad: RapidLock technology is a commercial roofing membrane attachment method, so we’re talking single ply membranes here, EPDM, PVC, TPO. And what RapidLock does is it provides you with a fully adhered membrane without the use of adhesives.
Janelle: How does it work?
Chad: The way that it works is, I think everybody’s familiar with the concept of hook and loop mechanical bond or attachment. So, if you think about those Velcro sneakers that you might have had as a kid, or even if you attach something to your windshield, say an E-ZPass or a toll paying system, most folks are familiar with hook and loop.
Velcro is the biggest name in hook and loop fastener. So, a lot of times those two concepts get confused. Velcro’s actually a brand of hook and loop fastener.
We’ve always had FleeceBACK membranes, which is a standard EPDM, TPO, PVC membrane with fleece on the back of it. And what we were able to do was optimize that fleece to act as the hook in a traditional hook and loop system, and then we attached a specialized spacer to the topside of the insulation to act as the hook.
When you make those two together, essentially what you have is a hook and loop attachment system. And we are using a different fleece than our standard fleece, in which we would use a two-part low-rise urethane. But again, when those two interfaces are put together, it creates a fully adhered, adhesive less attachment system.
Janelle: So, just to clarify, this isn’t specifically a Velcro roof, right? It’s some kind of Velcro-like technology?
Chad: Yeah. Thanks for asking. I know it can be a little confusing. It’s a bit of semantics, right? So, again, Velcro is the leading brand name of hook and loop fastening systems.
Technically, we’re not to call this a “Velcro roof.” However, we have been partnering with Velcro over the last five years to develop this system and it comes out of their Velcro brand securable solutions.
So, technically it’s a hook and loop fastening system. But we are working exclusively with Velcro to bring that to commercial roofing.
Janelle: Okay, that makes sense. What are the advantages of a RapidLock roof system?
Chad: First and foremost, it’s the fact that you don’t have any adhesives involved.
Anybody who’s worked with commercial roofing adhesives knows that there’s some bit of skill required in terms of application rates, storage of the adhesives, prior to and during installation, and also the temperature in which you install them.
The RapidLock system doesn’t have any temperature restrictions because there aren’t any adhesives involved. So, that becomes critical in the colder winter months when a lot of the adhesives on the market are 40 degrees Fahrenheit and higher, or even down to 25 degrees Fahrenheit and higher.
But there are a dozen states in the winter months [that] on average experience temperatures well below 25 degrees and you just can’t roof them.
Additionally, if you’re in an occupied building, we had mentioned VOCs earlier in the discussion, but VOCs and odors in occupied buildings can be very detrimental to the occupants inside in terms of reception.
You have to remember that a lot of the fresh air intakes are up on the roof, so any little bit of adhesive smell or anything that gets into the building can cause folks inside the building to be alarmed in some cases.
So, with this system, we think about hospitals, schools, occupied office buildings, since there are no adhesives involved, there are no odors.
And then additionally at the end of the job, there’s very little cleanup. So, traditionally, you would have rollers and pails, and cleaning materials and things like that.
At the end of these jobs, you just don’t have any of those adhesive application pieces that you normally would. So, those are the main advantages: cold weather, ease of installation and lack of clean up.
Janelle: Great. Let’s talk about RapidLock vs. other single ply solutions. Where is this particular product positioned?
Chad: Yeah. Thanks for asking that. If we think about a spectrum of commercial roofing products, specifically single ply, probably the one that everybody’s familiar with is what we would call “bareback membrane,” so PVC, PDM, TPO, without anything on the back of it.
So, standard membrane that you would use, what are called “bonding adhesives” to essentially glue that membrane to the substrate below it, many times, an insulation board or a cover board.
More recently, we’ve seen what we call self-adhered technologies that essentially have that adhesive or glue already applied to the backside of the membrane, which essentially makes it a peel and stick.
“When we compare the RapidLock system to a traditional bareback system with bonding adhesive, in our time trial studies over the last two years, we’ve seen up to an 80% reduction in labor on the rooftop.
“So, pretty significant—because you’re not standing around waiting for an adhesive to flash off, based on temperature and humidity changes during the job.” - Chad Buhrman
There’s a release liner on that back of that membrane that protects you from sticking that roof down until you’re ready to do so. You peel that off and then you stick it down.
The next type of membrane in line in terms of performance and quality would be a FleeceBACK system, as we talked about with the RapidLock system.
FleeceBACK membranes have that added security of that fleece, added performance of the fleece on the back of the membrane.
Those systems are typically put down with two-part urethane adhesives, so an A and B side that can be dispensed through various equipment—everything from a $40,000 rig that can handle 50-gallon drums to much smaller self-contained units that don’t need any equipment to dispense that have a self-contained tank system if you will.
And so, RapidLock then is positioned further down the line in terms of performance and value from those FleeceBACK, because essentially, it’s an enhanced FleeceBACK system.
It really is a FleeceBACK membrane system that doesn’t require any equipment or any adhesive-dispensing equipment because there aren’t any adhesives.
Janelle: What kind of training would you need to install a RapidLock system?
Chad: It’s actually pretty simple, but all of our approved contractors attend training prior to become a certified installer. And so, on the RapidLock system, it’s much the same. We have a training facility here at our campus in Carlisle. We have training facilities all over the country that we provide contractor training.
And if you’ve taken training within the last two years, you’ve likely have seen and had hands-on experience installing the RapidLock system.
It’s actually pretty simple in that again, there aren’t any adhesives. You don’t have to have any experience dealing with adhesives, applications, flash off times, etc.
There’s a release liner on the back of the RapidLock membrane, on the fleece membrane, that allows you to position the sheet exactly where you want it. It’s slit down the middle, so that when you get the sheet placed on the roof where you want it, you can then peel it off a half at a time and essentially attach that to the substrate below.
We use the term repeatably consistent because you’re going to get the same result just about every single time, regardless of the experience level of the crew.
You’re just going to get a predictable result and not have to deal with adhesives. So, it’s very simple and our folks that are being trained currently are seeing that system.
For contractors who have never installed the system before and let’s say have been to training five years ago, well, then we go out on the job site and we help them install the system, we provide assistance on the job site.
Janelle: So, aside from the release liner that allows you to kind of position and apply it, half at a time, are there any other installation advantages specifically?
Chad: Yes, Janelle, there are. And we talked about labor savings quite a bit. But to just put some numbers to it, because folks like to have a comparison.
When we compare the RapidLock system to a traditional bareback system with bonding adhesive, in our time trial studies over the last two years, we’ve seen up to an 80% reduction in labor on the rooftop. So, pretty significant—because you’re not standing around waiting for an adhesive to flash off, based on temperature and humidity changes during the job.
Additionally, when we compare a FleeceBACK membrane with two-part bonding adhesives or low-rise adhesives, those systems already go down pretty quickly because that two-part low-rise adhesive will be ready to apply at anywhere from a minute to two minutes, so very quick.
But we’re seeing a 25% labor savings when compared to low-rise urethane adhesives with FleeceBACK. So, overall, it’s just a super-fast way to put down membrane.
And many of the contractors that’ll voice a customer after an installation, we like to see how it went, what changes they’d like to see, what improvements they’d like to have made, most of them say, “Look, we’re installing these jobs with half the number of folks on the roof.”
So, they can cut their crew sizes down, which essentially means they can double the work because they don’t have guys dealing with pails and adhesives and roller, applying and waiting. You can just keep moving.
“Additionally, when we compare a FleeceBACK membrane with two-part bonding adhesives or low-rise adhesives, those systems already go down pretty quickly because that two-part low-rise adhesive will be ready to apply at anywhere from a minute to two minutes, so very quick.
“But we’re seeing a 25% labor savings when compared to low-rise urethane adhesives with FleeceBACK.” - Chad Buhrman
Janelle: Now, you’ve mentioned humidity and temperature a bit. But could you elaborate on cold weather installations and what temperature you would be able to install a RapidLock system at?
Chad: Yeah. So, we actually tested the system down to -40 degrees Fahrenheit. And folks may say, ‘Well, why did you pick that number?’ Well, that’s what our environmental ovens would go down to. So, that’s about as far as we went.
But we tested the performance of the system down to -40 in terms of our adhesive test that we would normally perform in our lab. And again, because there are no adhesives, there’s no concern about temperature. And the hook and loop bond is a mechanical bond, which isn’t a chemical bond. So, it’s literally unaffected by temperature.
You have to think about the temperature swings that a roof may see, depending on where you are in North America, you may see -20, -30 or -40 on occasion.
With a black membrane, you may see temperatures upward of 200 degrees on a hot, sunny day, where the air temperature is 100 degrees. So, pretty significant temperature swings, but we’ve tested it all on the high and the low side.
And again, the advantage of just being able to install year-round and not having to stop production on a roof because it’s too cold in the morning, or it’s even too cold for a week or a couple days, it just makes it simple.
Now, in cold weather, you may have to remove the snow before you can roof.
Janelle: Yeah. I guess that would be key, right? How does RapidLock compare to a traditional bonded membrane roof system in terms of just the system performance?
Chad: That’s a great question, because it’s interesting to watch folks’ faces when they first find out about this system. Because they kind of look at it, you hand them a sample, they put it together, they take it apart, and they look at you and say, ‘Really? Is this real?’
It is a little bit hard to believe that a hook and loop system exists for attaching roofs. It’s just not something that’s in our normal train of thought in terms of how you would apply it.
But that’s the advantage of the system is we took a technology that’s tried and true, it’s been used in many applications and we applied it to commercial roofing.
So, one of the things we had to do early on was make sure that we could actually pass a lot of the code requirements and the testing that’s necessary with commercial roofing, which quite frankly is very extensive.
And so, one of our key metrics in terms of system performance was factory mutual in being able to achieve an approval rating.
And a 1-90 approval rating is pretty pervasive in the industry and kind of the—I’ll say the cost of entry in terms of having a system that can pass that. And not only were we able to pass that in the field, but we were able to get up to a 225 pounds per square foot in the corners of a 1-90 system with RapidLock.
Additionally, we’re able to warranty the system for 20 years and provide a 90-mile-an-hour peak wind gust speed warranty. And as with all the FleeceBACK membrane systems that we offer, we have additional hail and puncture resistance on those as well.
First and foremost, the system really is a FleeceBACK system, which we position as our highest performing system. So, Velcro had to be all that and then some for it to pass our internal.
And we did years and years of testing, including years of field testing of actual application on actual buildings, watching temperature cycles through the seasons, etc.
So, there is extensive testing and our performance metric was we set the bar very high.
Janelle: So, let’s talk options. What product options are out there for the RapidLock system?
Chad: Currently, we have EPDM, in terms of membrane types, EPDM and TPO. PVC is in development and we hope to have that out by year-end or early next year.
In terms of substrates, so where the hook is applied, we have several installation options. So, those who are familiar with commercial-grade polyiso insulation, we have a glass reinforced felt, sometimes called a paper-faced product. We have a glass reinforced fiber faced product, which is sometimes referred to as GRF or glass-faced product. So, two different facer options.
Several thicknesses, thicknesses that’ll get you to your code requirement in just about every jurisdiction in the United States in a two-layer system. And we also have a half-inch high density board that acts as a cover board as a substrate too. And that’s an insulating cover board that’s a polyiso high density cover board.
So, various thickness of insulation, various facer types, various membrane types and a cover board option as well.
Whether it’s a new construction project or a re-roof or a re-cover, we feel like we’ve got all the product availability that you would need.
Janelle: At the end of the membrane’s life cycle, what do I do then? Can I just peel it off and replace it with another RapidLock membrane?
Chad: Yeah. That’s a great question. It’s one of the questions we get asked very frequently. Since it’s a hook and loop system, can I just peel it off and kind of put a new membrane on?
The short answer is at this point, unfortunately not.
We’ve optimized the hook and loop fastening system to work for maximum performance. So, we wanted to get the best uplift, the best overall performance.
If you think about a 20-year life cycle or roof and expansion and contraction every day and through the seasons and foot traffic and weather and storms and hail and etc., there’s a lot going on, on that roof.
We were concerned about peeling that membrane up. You may damage the hooks in some cases on that substrate board. Many times, you’re looking to add a cover board, add additionally installation based on code requirements, when it was done last time.
So, at this point, we’ve optimized for maximum performance over that 20-year period and not for replacement of the membrane at this point.
But who knows? Maybe in the future.
Janelle: Absolutely. Thank you, Chad.
Chad: Thank you.
Janelle: So, let’s tackle the other technology that we wanted to cover today. And that’s the VacuSeal vent-secured roofing system. Alex, can you explain to me how that works?
Alex: Yeah, thanks, Janelle. So, similar to RapidLock in what Chad just discussed, this system is also a labor saver for contractors, based off of the ease of installation and the less labor or amount of people on the roof that it would take to install this system.
For the VacuSeal system, Carlisle partnered with B2T Technology to offer it through a single-source channel.
Now, Carlisle has been working with B2T close to about 10 years now, and we do have several million square feet warranted by a CCM. However, with this new enhanced partnership, Carlisle will be providing enhanced technical and marketing resources.
Overall, what you have is a system that’s completely loose laid. So, if you’re familiar with roofing components, that would be the insulation, the cover board and the membrane, all three of those main components would be loose laid.
And they’re ballasted by specialized vents that utilize the power of the wind to create a negative pressure section to hold the system in place. And this vent layout is a specifically engineered system where we take into consideration different factors like the building height, the building location, the parapet wall heights, so on and so forth, to have a specialized engineered layout for these vents to make sure that there’s enough negative pressure to hold all the roofing components in place.
Janelle: Great. Can you elaborate a little more on the science behind the system? How does it actually stay put?
Alex: Yeah. So, the system in vents create a negative pressure through a principle called the “Venturi Principle.” What this states is air is accelerated on top of the roofing system and passes through the vent itself.
At the same time, these vents will suck air out from underneath the membrane and this is what creates a negative pressure to hold everything in place and really create a vacuum seal, locking all the roofing components that would be loose laid in place.
So, essentially, the faster the wind blows, the greater the negative pressure that these vents create, and the greater the pressure are the backing seal to hold all the roofing components in place as well.
Janelle: So, how is that system installed? Can you kind of give me an idea of the different components and what sequence you might install it in?
Alex: Working from the deck on up, first the most important factor of this system is to have a complete air seal at the deck level, whether that be a concrete deck or a steel deck or whatever the case may be, you always need to have a complete air seal at the deck level.
This seals the deck to create that negative pressure as these vents are working to create that negative pressure to hold everything in place.
Typically, an air seal is achieved by either the deck type or by various air and vapor (unintelligible) depending on the deck type.
Next, you would have the insulation that’s specified for the project and the code requirements for that specific project.
Again, these components are loose laid, so the insulation would be loose laid. And then on top of that, a requirement for a half-inch cover board that is specified by the manufacturer. So, consult with the manufacturer to understand what would be that requirement for a half-inch cover board, like a gypsum cover board. And again, that would also be loose laid.
Then the system is compatible with all three membranes, so EPDM, TPO and PVC membranes, all bare-back membranes, so it’s not compatible with a FleeceBACK membrane. But again, those membranes would be loose laid with a 60-mil requirement for a 20-year warranty.
So, looking specifically at the VacuSeal components, first and foremost, you have the air distribution strips, which are installed above the cover board, in between the cover board and the membrane. And the main objective of this component is to facilitate air movement under the membrane and push the air to the vents themselves, so the vents can pull air out through the vents, creating that negative pressure.
“We’re saving our contractors labor and time on their roof so they can get to the next job.” - Alex Drescher
Now, these air distribution strips are typically 10-inch-wide strips, specific components for a VacuSeal system. And these are installed in a fashion where you’d have three strips coming together to a point from the perimeter location. Typically, around 20 feet inward from the perimeter. And these vents would also be placed typically 20 feet apart from each other.
So, once you’re installed the air distribution strips on top of the cover board, you would kick out the membrane, again compatible with EPDM, TPO, and PVC membranes at 60-mil thickness. And as you kick out the membrane, you’re going to mark the location for the engineered drawing and layout, where the vents will be located.
So, as you kick out the membrane, you’re going to mark the location and cut a 10-inch diameter hole in that location so that you can flash the vent at according to the specifications.
Janelle: Compared to some more traditional fastening methods, what are some reasons why you might choose VacuSeal over a more traditional way of fastening?
Alex: There are many benefits to the VacuSeal system. And you will find very close ties here with the RapidLock system, with some of these benefits.
Some of them include reduced installation time. So, no fastening or adhering the insulation cover board or membrane. That’s a huge benefit and time saver. No cold weather limitations like you would have with using adhesives. Again, this is a completely adhesive-less system so you wouldn’t have flash off times as well as cold weather limitations.
The vents themselves are made out of durable UV-resistant PVC and there’s no moving parts to the vents, which adds durability to the overall system.
And without using adhesives, there’s no VOCs or odors, again, as we move to more environmentally friendly systems and types that we need to abide by, this system is a great addition to that toolbelt where we wouldn’t have VOCs or odors.
Janelle: What are some key things that you recommend people keep in mind when they’re installing this system?
Alex: There are two main things to keep in mind when installing a VacuSeal system.
The first thing is the edge in your layout. And again, that’s the first step in the process of evaluating any project to make sure that VacuSeal is a fit for that particular project.
And in that process, what we do is an evaluation to ensure it’s the right fit, whether that be the deck type, the building location, the wind zone and if the size of the building is enough that we can create negative pressure utilizing these vents.
If VacuSeal is a great solution, the engineered layout is completed, and it shows the vent and distribution strip layout. This is important as the negative pressure is calculated to hold the roofing components in place.
During this process, we take into consideration things that I’ve already mentioned, like the building location, height, wind zone, any penetrations on the roof, all these things take into consideration to maximize the performance of the vents.
The second key area to keep in mind when installing a VacuSeal system is completing a complete air seal at the deck level.
And again [...] make sure that you consult with the manufacturers details to ensure that we are creating a complete air seal at the deck level. And this is at different deck types as well as different penetrations as well.
Janelle: So, as far as takeaways from our discussion today, what do you feel are some of the best applications to utilize the VacuSeal system and technology? How do you know it’s a good fit for your building specifically?
Alex: Great question. So, VacuSeal is a great alternative to ballasted or mechanically fastened systems. We do consider this a wind or vent ballasted system. But you’re just using it as an alternative from typical stone ballast.
It’s also perfect for a retrofit application. So, keeping the existing system in place, especially if that existing system already creates an air seal, like a built-up rift or a fully adhered system. Many times, there’s already a complete air seal at the deck level.
So, what you’re able to do is go directly over with either and then necessary insulation to meet the code requirements in that region. Or most often, you can just go over with a loose laid gypsum cover board and then the membrane itself and then the vents and the VacuSeal-specific components.
Lastly, VacuSeal is a great solution for a substrate decks, like concrete decks where the customer does not want to adhere or fasten through the deck. You can just use the system like you would as a stone-ballasted system that you would traditionally do.
But ultimately, again, tying back to some of the main benefits here, it has no cold weather limitations, you can install a system throughout the winter months.
And finally, really to the point of this conversation is reduced installation time. We’re saving our contractors labor and time on their roof so they can get to the next job.
Janelle: Excellent. Guys, thank you so much for joining me today to talk about alternative attachment methods.
Chad: Thank you, Janelle.
Alex: Thanks, Janelle.
Janelle: This has been Janelle Penny, editor-in-chief of Buildings magazine. And thank you for joining us today.
Listen to the other two installments of this Carlisle Roofing Series: