Intro to Low-Slope - PODCAST TRANSCRIPT

Editor's note: The following is the transcript of a live interview with Rob Keating and Tim McDermott of Mule-Hide Products. You can read the interview below, listen to the podcast or watch the recording.

Intro: Hello, and welcome to another Lunch and Learn from Roofers Coffee Shop. My name is Heidi Ellsworth, and, today, we are here with what I think is just an amazing Lunch and Learn, especially for those of you who are new into the industry and just kind of wondering, "What does all of this mean out there when we talk about low-slope roofing?" This is an intro to low-slope roofing brought to us by our friends at Mule-Hide Products, and, today, we have Rob Keating and Tim McDermott who are going to be helping us understand what is low-slope roofing.

Heidi J. Ellsworth: Before we get started, a couple of housekeeping items. First of all, don't forget to download your discussion sheet. On the discussion sheet, as you're going through this Lunch and Learn, you'll be able to take notes so that, at the end, you can go online to Roofers Coffee Shop and take the quiz. With the quiz, you'll get a certificate of completion that you can show off to all of your friends and fellow workmates and also have your name put into a drawing for a free lunch. So, be sure, get the discussion sheet and do the quiz afterwards. Hopefully, you are all sitting around lunch right now as a team watching this and having some great discussion around it. That's what this is meant for, that fun lunchtime, learning a little bit more about roofing.

Heidi J. Ellsworth: So, let's get started. First of all, again, I'd like to introduce our wise guests, starting with Rob Keating. Rob, welcome and can you introduce yourself?

Rob Keating: Oh, thanks, Heidi. Yeah. My name is Rob Keating. I'm the regional director for the Northeast for Mule-Hide Products.

Heidi J. Ellsworth: Awesome. And, Tim, can you introduce yourself?

Tim McDermott: Hi. Good morning, guys. My name's Timothy McDermott and I cover territory of Connecticut and Western Mass.

Heidi J. Ellsworth: Excellent. Today, we have three learning objectives, as we always do. The first learning objective being understanding the differences between low-slope and steep-slope roofing. The second learning objective being understanding the types of low-slope roofing products. And third, we have understanding the basic components of low-slope roofing. Great stuff, so let's get started.

Heidi J. Ellsworth: Starting out, really understanding the differences between low-slope and steep-slope roofing, Tim, if you could start, let us know how that works. What are the terminologies, and what are the differences?

Tim McDermott: Yeah. It can definitely get a little confusing when you're talking to a seasoned roofer, the jargon, the terms they use. So, we're going to help simplify that and walk you through. To begin, low slope itself, also referred to as commercial roofing or flat roofing, the important thing to remember versus a shingle roof, which is considered a steep slope, is that low-slope roofing generally has a 2/12 pitch or less. So, what that means is, as you come across 1-foot measurement, you have a 2-inch height or less. So, 6/12 slope would be 6 inches and you'd have a severe angle. Low slope is completely waterproofing. That's the biggest takeaway when we're talking about that versus shingles, which are water-shedding. Generally, a lot of low-slope buildings you're going to see if you're catching a plane landing at local airport, a lot of flat buildings. Hopefully, after today, you start seeing it more and more as you walk around.

Heidi J. Ellsworth: I love it. One of the things that I hear a lot is flat roofing, and that's very actually international. We hear that a lot more flat roofing coming from Europe, but is flat roofing and low-slope roofing the same?

Tim McDermott: Yes and no. There's no actual flat roof. There's a design where maybe the structure is built flat and now we're adding some kind of device, whether it be sheets to add a taper, so a higher height on one side. But any roof you're going to have, you always want positive drainage, right? Water is probably the most destructive element on earth. I try to remind people, "It made the Grand Canyon," so we want to get it off the roof as soon as possible, whether to drain internally through the building or off the roof to a gutter system.

Heidi J. Ellsworth: That's great. Rob, a lot of times, again, we have people refer to commercial roofing or residential roofing and this kind of gets mixed up in that low slopes, steep slope. Can you give some definitions of what commercial versus residential and how that all works together?

Rob Keating: Yeah. Sometimes, people will call commercial roofing just any kind of low-slope roofing. It's a common misconception as well. Whereas, a commercial building, say a hospital or a school or a church can still have a steep-slope roof on it. We tend to stay away from calling this commercial roofing and try to stick to the low slope term because you're really looking at the fact that it's a 2/12 or less slope pitched on the roof versus it being a commercial building defining what the roof is.

Heidi J. Ellsworth: And when you think about it, there are plenty of low-slope roofs over homes, especially in the southern states. Yeah, that doesn't really define it. Rob, along that same line, I know Tim just said looking at shingles and I think a lot of people just think of that, shingle roofs, but there's a lot of different types of steep-slope roofs. What are some of those, just to kind of help it on the products that should be on steep slope compared to the products that should be on low slope?

Rob Keating: Yeah. For steep slope, you can use shingles or metal or tiles, in some cases in the south or the west, versus low-slope roofing, which is typically a membrane or a rolled sheet good of some kind or, some cases, could be a liquid-applied roofing system as well.

Heidi J. Ellsworth: Excellent. Okay. Tim, let's talk a little bit about the history of low-slope roofing. I know people think history, history and roofing, but really it's very rich. Can you tell us a little bit about that?

Tim McDermott: Sure. We don't have a long history for roofing. Originally, it was hot asphalt, so I always like to refer to the movie Shawshank Redemption, if anyone has seen that movie, where they're up on the roof and the guys are literally putting in mops in these hot tar buckets and they're spreading around for that six pack of beer. That was the original roofing. A lot of innovation has come from that point, although, because it is the most soundproof roof that existed, there are a lot of guys that still truly believe, mostly that have a lot of white hair, that it's still the best system in the market. You'll see areas probably in your home cities... If you're in Florida, that's a big market and then Chicago as well. Because it was so dangerous, the high temperatures getting on your skin, the potential for burns, et cetera and just the conditions, I don't know if anyone's been on their roof in the summertime where it's already hot and then adding in 100 degree asphalt mopping around, it's not the most fun market to be in.

Tim McDermott: Because of that and the rising due to cost at the time in the '60s, PVC actually came pretty prevalent as the first membrane used as a replacement for that asphalt. It's not the same PVC that you'd see and you'd trim, like some of those kind of house projects you're doing, but more of a pliable sheet. EPDM, which a lot of people refer to as just rubber, came out in the '70s. Same kind of deal with the prices of PVC and asphalt, something lower cost to kind of attack the market. And then, finally, my favorite product, TPO, actually came from the automotive industry and landed around the '80s, '90s. And right now, it's pretty predominant in most other areas in the entire US today. It's the baby of the family, but it's for sure the fastest growing.

Heidi J. Ellsworth: Yeah, it is just been that progression. I've been watching that myself in my career, the progression on these new materials. And, Rob, you just mentioned, a minute ago, liquid-applied roofing. That is kind of that next thing that's following TPO. Tell us a little bit about that.

Rob Keating: Well, liquid applied is the newest and biggest growing segment of the business. And it's actually been around for quite some time too, but it continues to evolve. Couple of reasons that liquid applied has become so popular is because you're reducing waste, you're not throwing anything off the roof, you don't have to tear off a roof and fill up landfills, so environmentally much safer. You're reusing what you already have there, so you're kind of recycling your roof and restoring it with a new product. There's a lot of great benefits, and it's also low barrier to entry. You don't have to invest in a lot of equipment. It's kind of simple to get into that segment. So, liquid-applied roofing is definitely a growing segment for, not only the industry, but it's especially a focus for us at Mule-Hide Products. Silicone roof coatings are a high priority for us around the country.

Heidi J. Ellsworth: Yeah. And when you really look at the history and the evolution, all of these low-slope solutions have their places. I love, Tim, what you said. Certain markets are still very much about a buildup roof and asphalt, hot asphalt. But now all the way up to liquid applied, we're really seeing people trying to fit their low-slope products to the area that they're in and the needs of the building. Tim, you're nodding.

Tim McDermott: Yeah. I find a lot of success with guys generally that are coming from the shingle world. Maybe they found themselves with a contract of a flat roof. To Rob's point, instead of investing in generators and all these robots and expensive tools, getting a 5-gallon bucket of silicone and essentially painting on the ground couldn't be any easier for a lot of these guys.

Heidi J. Ellsworth: So, all the different options when you're talking about low-slope roofing.

Heidi J. Ellsworth: Tim, let's talk about the basic components of a roof, of a low-slope roof.

Tim McDermott: Yeah. Hopefully, I can explain this, how I learned it. I came from zero experience in the roofing industry, so I think I have a pretty good way of doing it. I'm a big foodie, so I like to relate a lot of things to food. I like to think of a low slope root as an open-face sandwich. It's just that easy. So, you have three components. You have your deck, which is the actual top structure of the building. I like to think of it as a nice hearty bread. You're going to have an installation or cover board on top, and that's going to be your meat of choice. And then, finally, you have your roof cover, which is going to be your membrane, your liquid applied and that's going to be the slice of cheese. So, if you can remember an open-face sandwich, that's as complicated as it gets for low-slope roofing.

Heidi J. Ellsworth: Rob, and when you kind of look at that, I mean that's just a great description and that really... I mean, there's a lot of intricacies that go in that, but the basics, talk a little bit about that.

Rob Keating: Yeah, it's very simple. When Tim simplifies it like that and you just think of... you just have basically three basic components that go into a roof, your structure, your installation board and then your waterproofing, which is your membrane, which in the past as we talked about was a multi-ply system and we've evolved into a single-ply system, one roll that goes down, applied at once. Your sandwich got a lot less layers, which I know that disappoints Tim. You need some more cheese, some more meat, those multi-plies. Our sandwich has got a lot simpler as the roofing industry evolved.

Heidi J. Ellsworth: Yeah, there used to be a lot more cheese on it, I'm just saying.

Rob Keating: Yes, condiments, the whole nine. You can still add all those things.

Heidi J. Ellsworth: Yeah.

Rob Keating: You can jazz up your roof system any way you want, condiments, cover boards. There's a lot of ways to enhance it, but that's the basics.

Heidi J. Ellsworth: Maybe we'll talk vegetables. And then, in the next one, we can talk garden roofs if we stay on this theme. Sorry, that just cracked me up.

Heidi J. Ellsworth: Okay, so let's go to our second learning objective, which is understanding the types of low-slope roofing products. So, we're going to start with the bread of the roof deck types. So, Rob, can you talk about the different types of roof decks out there?

Rob Keating: Sure. There's multiple types of roof decks, and I'll start with the most common and I'll go to the least common from there. Most common will be your steel deck. So, if you look up inside of a building and you see metal that looks kind of like a W almost repeating itself, that's a metal deck. Typically, that type is a V-deck is the term for it. Basically, it's steel and they lay it out, long sheets, 22 gauge thick and that's your most common deck. Second most common I would say would be wood, typically plywood would be that structure, solid, cheap for buildings, works out very well, continuing to go into more specialized down that path. Then, you have structural concrete, which was much more prevalent, old buildings, when they were pouring concrete for safety or anything else, but now costs too much. So, typically, you don't see as much concrete.

Rob Keating: After that, we also have cementitious wood fiber. So, that is a technical term, but most people in the industry would know it as the brand name, which is Tectum. Kind of like the Kleenex brand, everyone just refers to it as Tectum even though the technical term is cementitious wood fiber. And then, last, we have gypsum, which is similar to the drywall you would see on a wall, much thicker, much more dense, can be plank, which is wide planks that are placed on steel beams or poured in place. And then we also have lightweight insulating concrete, which is a cheaper version to insulate your building prior to the evolution of polyiso and other items that can insulate your building from the outside, from that middle part of the sandwich.

Heidi J. Ellsworth: Yeah. Okay. Well, then, let's go to that. So, Tim, talk to us about insulation and cover boards.

Tim McDermott: Yeah. You have a small variety, not to confuse you, but polyisocyanurate, which is referred to in the industry as polyiso or iso board, think of it kind of like a foam with a cover facer on the top and bottom. And what this does is it gives you insulating value on the top of the roof and then it also gives you a nail bowl or glueable surface. When I was learning about insulating the top of a building, I was pretty confused because, being a homeowner, you see insulation in your attic, you don't see it on top under the shingles.

Tim McDermott: The reason for that, according to local building code, is that if you have insulation on the exterior of a building, you actually have the amount that is required. Insulation is very expensive, so local code for me is R-30, which would be two layers of 2.6-inch thick boards of polyiso. But if you were to put the insulation inside the building, doubling that would be R-60, right? So, the benefit is two-fold. You have half the amount that you need to meet code and now you have a surface to glue or fasten to. So, polyiso, which comes in a 4 x 4 or 4 x 8 sheet, is the most prevalent that you're going to see on top of the roof.

Tim McDermott: With that in conjunction, we talked about flat roofing not actually being flat. So, we have tapered insulation, which is a preformed 4 x 4 sheet and it starts small, let's say an eighth of an inch and then goes to a quarter of an inch and they're labeled A, AA, AAA, QQ. Essentially, when you're trying to design a roof and you have drains in the center of the roof, you have pitches coming up on the exteriors pushing the water. If it's a gutter system, sometimes you just have a built up of insulation on one side and you have one giant slope on the end.

Tim McDermott: Now, in conjunction with that, there are other products, not as common. The second most common one you'll come across is called EPS, which is an expanded polystyrene. And if you've ever had the old coffee cups in the hospital, the styrofoam cups, that's very similar to what it is. So, it gives an insulating value. There's no cover on it. If you were to apply glue, it would literally melt right through that. You use that in conjunction with a cover board, something harder that you're able to glue or fasten to. You're probably thinking, "Well, if polyiso does both of those, why the heck would I ever need EPS and a cover board? Seems archaic." Well, when Rob was referring to that V-deck metal roofing and you have all these grooves and slots, that's obviously not a flat surface for these membranes that sit on it.

Tim McDermott: So, the EPS can be designed as a flute filler, meaning that you take the square board, they pre-cut it in the factory to fit in those grooves and now it's a fill in between the metal for the slots. On top of that, you'd put the cover board and now you're off to the races with whatever design you're looking to do.

Tim McDermott: So, polyiso, polyiso tapered insulation and then one more polyiso product is called HD polyiso. So, it's a half-inch board, generally referred HD, high density and that gives a higher impact resistance. So, if you're building a flat roof over your garage for residential or if you're doing a low-slope commercial roof and you know there's going to be guys up there for maintenance if you have a deck on there for having parties or anything like that, you want to make sure there's more impact resistant on the roof deck below the membrane and that's what the HD polyiso provides.

Tim McDermott: There's other products in the market. A lot of other buildings don't necessarily need insulation value, they just need a board to fasten. So, you hear these terms go over and I'm sure there's some people that have a house where you have two, hopefully not three, layers of shingles, just put one on top of the other until you take care of it down the road. So, if you're doing an existing low-slope roof and it's sound and the insulation is dry and you just want a new layer because it's cold or you think it's going to prematurely fail, you can put down a piece of wood fiber board or a glass mat-faced gypsum board, which essentially will give a fire rating with the system. So, you just have a flat 4 x 8 sheet board you put down and then a new membrane on top.

Tim McDermott: Just to recap, because I know that's a lot, almost like a fire hose, polyiso is what you're going to come across. There's tapered to add or you could use EPS as a filler with a cover board or just the cover board and then you're off.

Heidi J. Ellsworth: Excellent. As you're kind of looking at that insulation too, just so everyone really... that is such an important ingredient within that sandwich, but just because of what the demands are for energy savings, for protection of the building, all of that. So, Tim, just a little bit, why is that insulation in those cover boards so important to that roofing system?

Tim McDermott: A lot of it has to do with the holding power. When you talk about failure, the bad stuff, addressing first, you're talking about roofs that are lifting off or prematurely failing, the misconception is that the membrane glue wasn't good and now it's falling off. But really when you talk about the connection to the roof itself, that cover board or insulation is the holding power for the low-slope roof. The membrane is merely the waterproofing aspect, right? So, insulation, if you leave out in the rain, it's going to be a dud. You have to get it replaced. So, it's important to mark the weather but also put it down in conjunction. The method of attachment on any roof is by far the most important, even shingles, right? You require generally six fasteners per little tab. You have to follow the guidelines of the local manufacturer to prevent any nightmare situations down the road. And that's primarily where we find a lot of the issues.

Tim McDermott: So, on a typical low-slope roof, you'll have a fastening pattern. Let's just say you need eight fasteners per sheet, and some guys will just go on the very perimeter of the board and there's no holding power in the center of it. That would be considered a failure for inspection, but also down the road an issue with it because wind, other than water, is very destructive and the wind's strongest in the corners and then on the edges right over. And if the wind can get under and start pulling, the rest of the roof's going to come right up.

Rob Keating: Just to jump on what Tim just said, just because what you asked was the importance of the insulation and the cover boards, I don't know... We got off on a tangent and went ahead a little bit with fasting patterns and whatnot, but I think the point we would want to make is that the importance of insulation is to just protect the building and protect your investment in the roofing system. Because if you don't insulate it well enough, it can cause major issues down the line. And if your heating and cooling costs go through the roof, whether you live in a warm climate or a cold climate, if you don't insulate it properly, it doesn't matter what color the membrane is, black, white, gray, it doesn't matter. So, having the correct amount of insulation is key.

Rob Keating: The importance of cover boards ultimately comes down to two things. If you're trying to achieve a fire rating, that's one thing where you would use cover boards in a certain way. But on the other side, cover boards enhance the performance of your roof system. So if you're looking for a specific amount of wind that a roof system can handle, you would design it as such with a certain cover board and a certain fasting or attachment method.

Tim McDermott: That's a great point. Thank you, Rob.

Rob Keating: Of course.

Heidi J. Ellsworth: Excellent. Okay. Well, then, let's move on to that protective waterproofing layer above the insulation and that is the roof coverings. Rob, can you continue and talk us through that?

Rob Keating: Sure. As we spoke about before, the most basic and common types of membranes right now are single-ply. The three types of single ply are EPDM, which is a rubber, to simplify. It's black, white or gray. We also have TPO, which is the biggest and most common type of roofing membrane in the country, which is a thermoplastic, so different than rubber, different installation method. The seams are welded together to create a monolithic roof, whereas EPDM is vulcanized and seam tape is used to attach the sheets together. The third is PVC, which is very similar to TPO. It's another thermoplastic. Some would say it's a higher-end, handles animal fats and grease slightly better than TPO, so you'd see it more commonly in restaurants or, say, a place where an airport where a jet fuel could potentially fall into the roof. You're going to want to use PVC on those roofs.

Rob Keating: And then I'll continue with the roof coverings. The other common types are modified bitumen, which is that multi-ply system that we talked about. Hot tar is the evolution of that. It's evolved into rolls. So, we sell both modified bitumen in a self-adhered version, which peel and stick, very simple, seen on a lot of residential situations because it looks really nice, can match your shingles. And in the same exact style of product, modified bitumen also comes in a torchable product. So, instead of peeling and sticking, you would torch it down and that's kind of going to the wayside slowly but surely because of insurance costs and danger and just having an open flame on a roof is usually questionable.

Heidi J. Ellsworth: Of course, I just don't want to leave this out, what we talked about earlier, liquid-applied roofing. So, Tim, just as we're looking at that as that final, not final, there's other ones out there we know, but as our top forms of roof coverings.

Tim McDermott: Yeah. So, there's a couple of different options out there. The evolution of the market, do-it-yourself friendly, longer lasting products. The takeaway with a lot of these either rubberized or silicone or acrylic-based products is you have to have an existing roof, right? This isn't where you're designing a roof, you put the insulation down and you're going to pour all this fluid on. They're restorative, which is the benefit. Someone has a roof that's 10, 15, 20, 30 years old, it's still nice and waterproof, it's still strong, but you just know you want to do something on it to extend the life. So, typically, you'd see an application where you'd use over an existing membrane silicone and essentially you're cleaning off the roof with a cleaner. You're going over the seams with either a liquid-applied tape or some kind of tape to make sure it's still waterproof. And then the silicone layer will essentially be poured, spread out in place on a very thin amount, generally around 24 mils, dried, so you think sheets of paper. In a couple hours, it hardens and it's ready for the weather.

Tim McDermott: If you have a metal roof system on low-slope or commercial, another opportunity is to use acrylic. So, a lot of guys from the painting industry can use the same equipment and you're essentially spraying on a paint color, which gives a waterproofing option and now you have a variety of colors if you want fire engine red or forest green, et cetera. And then the last one is rubberized asphalt. Some of those archaic, old torched-down roofs, the self-adhered, the mod bit with a lot of asphalt and oils, some people don't really want to approach that just painting something on. So, you have a similar component, rubberized asphalt, emulsion coating where you'd pour it on. It fills in all these little cracks and it still gives a beautiful monolithic layer. So, band-aids versus long-term, I would say rubberized asphalt is a band-aid, acrylic and then long-term solution, silicone. It could be the last thing you have to put on the roof for the next 50 years.

Heidi J. Ellsworth: Wow. So, one thing you said earlier that I want to point out to everyone is you can also have low-slope metal roofs, right?

Tim McDermott: We see it all the time.

Heidi J. Ellsworth: And is that something that's still popular or we've seen that still a lot, like on the barrel roofs, although maybe that's not low slope?

Tim McDermott: We actually accomplished a barrel roof at a military base. It was a big job, and they were able to fluid apply it. Obviously, bending membranes over and the high hide and the circumference, a lot of thought goes on versus just pouring on some silicone and spreading it out. But to Rob's point, metal is probably the most prevalent roof deck you're going to come across, right? It's easy to install, it's less expensive than other systems in the market and, at the end of the day, you're just putting something down for the bread to make that sandwich. So, a lot of people want to use something that's fast, easy and cheaper or less expensive to put down just as a base. Plus, structurally, steel will give more holding power than, say, typical wood generally.

Heidi J. Ellsworth: Great. Well, thank you, John.

Heidi J. Ellsworth: And let's go to our third learning objective, and that is understanding the basic components of low slope on roofing. So, first, let's start with preparing the roof. Rob, let's go to you. What are some of the things right up front that you should be doing when you're preparing the roof?

Rob Keating: It's two options here. Som if you have new construction, then that's simple. You know what you're doing. You're building your sandwich. It's very simple. You go through your layers and you're good to go. But if you are going into an existing roof that you're going to need to tear off or potentially do a recovery system or go right over the existing roof with a new membrane, first thing you would need to do is a core cut and what is a core cut? It's basically cutting a hole in the roof down to the deck to see exactly what you have there. This will show you multiple things. It'll show you the amount of layers on the roof, whether you can do a recovery per code. There's only a certain amount of roofs you're permitted to put on a building. Is it wet? What type of insulation is there? And is the building structurally sloped, or do I need to install a tapered insulation of some type? So, it shows you a lot of things.

Rob Keating: And then, at that point, you can move on and start designing your roof system and making those decisions. Second, and is more common for liquid-applied roofs, would be an infrared scan, which you basically will scan the roof from moisture, measures the heat differential between the lower layer and the top layer, typically done at night and you can see your hot spots and that's where your moisture is contained in the roof. So, you can evaluate whether you can do a liquid-applied roof or even a recovery system.

Heidi J. Ellsworth: So important, like you said, no matter what the roofing system is, you don't want to trap a bunch of moisture in the roof.

Rob Keating: No, that is not going to end well.

Heidi J. Ellsworth: No, it's not going to end well.

Heidi J. Ellsworth: Okay. So, Tim, then let's talk about building the roof. How are you building that new roof?

Tim McDermott: Yeah. The design of the roof other than method of attachment is definitely going to be something that's overlooked by a lot of people. And generally, if you have architects involved, they're already educated on this. You really have to look at the character of a building, right? Any city in the entire country, you could have low-slope buildings next to each other. One could be a general office where maybe they want to save on the heating costs and you're looking for a black EPDM roof to absorb a lot of heat. Right next door could be a hospital where they're running AC machines 24/7, the amount of people and electronics, so you want a lighter color of roof to reflect off. Not to get too much into the weeds, but you think about manufacturing facilities, these plants. They have generally long I-beams that run across the ceiling, a lot of vibration, so products like built-up roofing, the self-adhered mod bit have a very low elongation. So, basically, that vibration could cause premature failure on the seams.

Tim McDermott: My famous one is talking about a local Dunkin Donuts or a Burger King. If you use an EPDM membrane on that, generally, those buildings will have grease traps, they go through the roof into a bucket which becomes a maintenance item and guys generally let it overfill. It floats onto the EPDM and that animal fat ends up eating through the EPDM and you end up having a whopper of a problem. That's my only dad joke. So, on a situation like that, that's where you start looking at the chemical resistance and animal fat resistance of TPO and PVC. So, really think about the character of a building versus just waving a flag of, "We're only doing silicone," or, "We're only doing EPDM," really, having the best service for that building for long-term solutions.

Heidi J. Ellsworth: Yeah. That's so true. One of the things we haven't really talked about is the fastening. How are you installing? What's the fastening attachments used for this roof? So, Rob, talk a little bit about how important that is and the types of fasteners.

Rob Keating: Okay. Again, this is the most important part of a roof. I think we mentioned it earlier. But the key to a successful roof is proper fastening, attachment of that insulation board, because that or cover board, is ultimately what's holding down your entire roof system. So, we have specific fastener patterns that we publish. Not going to get into the details with those, but they're available on our website, mulehide.com, per roof system. So, if you're doing a certain type of system, we have a certain type of fasting pattern that holds your entire roof system down. We have multiple types of fasteners depending on the roof decks, like we mentioned before.

Rob Keating: Just standard for metal, we have three different types of fasteners for metal that you could use, all work and all accomplish different things but all require one thing that's very important, you need a plate. For every fastener you put in, you need a plate. So it takes your surface area from... call it a dime to 3 inches or 2 3/8-wide. A lot of people don't realize that you need to have the plates on the insulation because that's holding your entire roof system down. Again, the importance of evaluating your system, knowing what you're installing into, determines what you will fasten with.

Rob Keating: We also have specialty fasteners depending on the system for Tectum or lightweight or gypsum. Not going to get in the weeds with those, but they're available. We have an option for any type of decking. On the other side of that, if you could not fasten, we have a low-rise foam adhesive. So, what this is is a two-part polyurethane adhesive. You spray it onto the roof deck surface, typically concrete and then you would lay your insulation boards onto it. This will be used for situations where you don't want fasteners penetrating through the roof deck or it's just concrete. It's simpler, faster, neater, easier. So, it depends on the system. But either way, your fastening methods are very important, whether it's glue or fasteners.

Heidi J. Ellsworth: And it sounds like it's very important that you follow the rules with those fastening patterns.

Rob Keating: Correct, yes. You don't want your roof blowing off because you try to save on six fasteners on a board.

Heidi J. Ellsworth: That doesn't work out well for anybody.

Rob Keating: No.

Heidi J. Ellsworth: No.

Heidi J. Ellsworth: So, Tim, just kind of some of the last thoughts on installation on some of the different things to be thinking about. I know there's a lot of people talk out there about ballasted, thermal bridging. Can you talk a little bit about that?

Tim McDermott: Sure. I mean, when you break it down and I try to simplify everything as much as I can. I know it's very complicated, but there's really three ways to hold down the membrane and that's fully adhered, which is you're literally putting glue on the cover board or insulation and membrane, letting a tack off or let the chemicals work and then it's a contact adhesive. The second option is mechanically fastening, literally just putting down those screws and plates as a holding power. And then the final is ballasted. It's a pretty complicated system. You put the membrane down and you pour a bunch of rocks to hold it on. I'm sure if anyone stayed at a hotel recently, you have that beautiful view of a roof. You see all these rocks and you're thinking, "What the heck is going on?" Well, that's literally what it does. The rocks hold down the entire roofing system, which is an archaic system. People generally don't do that nowadays, but you do come across it pretty often.

Tim McDermott: I also talk about the method of attachment a lot. So, the gluing option is generally preferred. It's usually faster, cheaper for a lot of guys. They're pouring out the glue, rolling off the membrane and you wonder, "Why would I ever do mechanically fastening?" Well, you're limited in temperature guidelines. So, in the Northeast, we probably have two months of summertime weather and the rest is winter. So, when you can't glue because it's too cold, you do have the option to fast and that's generally where it comes into play.

Heidi J. Ellsworth: Well, gentlemen, thank you. Wow, what a great... I learned a lot and I've been doing this for a while, and so thank you so much for this introduction to low-slope roofing, some great information. And like you said, all of this information can be found on Mule-Hide website along with the directory on Roofers Coffee Shop. Just look for Mule-Hide and you can find information along with a lot of other great webinars and PowerPoints that can really help you through understanding this, if you're not in the industry or if you just started and you really want to get on top of all this.

Heidi J. Ellsworth: So, Rob, Tim, thank you so much for being here today.

Rob Keating: Thanks for having us, Heidi.

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