Everything you Need to Know About Restoring Metal Roofs - PODCAST TRANSCRIPTION

Editor's note: The following is the transcript of a live interview with Greg Hlavaty from Western Colloid. You can read the interview below or listen to the podcast. 

Karen Edwards: Hello and welcome to the Understanding Roof Restoration Podcast. I'm your host, Karen Edwards from askaroofer.com. The Understanding Roof Restoration Podcast dives deep into the topic of restoring roofs. As the popularity of roof restoration continues to grow among building owners and contractors, there are many questions that arise with a wide variety of roofing systems on existing buildings and many available restoration options. We turn to the experts at Western Colloid to answer your questions on roof restoration. Greg Hlavaty, Hal Leland, and the team at Western Colloid have been manufacturing and installing these systems for more than 50 years, and they have seen it all. We will tackle a different topic each month and answer questions submitted by you, our listeners.

Hi everyone. Welcome back to another episode of Understanding Roof Restoration. I'm Karen Edwards and I'm really excited to welcome Greg Hlavaty back to the podcast. Welcome back, Greg.

Greg Hlavaty: Good to be here. Thanks for another great month of podcasts.

Karen Edwards: Oh, excellent. Yeah. So before we jump into this month's topic, which is all about understanding metal roof restoration, I just want to mention that I saw some photos from the RCMA summer meeting last week, and it looks like you won an award. Tell me about that.

Greg Hlavaty: Yeah, I did and it was a very pleasant surprise. I was very honored to receive it. The board of directors gave myself and one other, Will Lorenz, who has also been past president, an award for contributions to the association, to the board of directors, serving on committees and in general to the roof coating manufacture, the roof coating industry in general. So I was pleased to be recognized by them in that, proud of that.

Karen Edwards: That's quite an honor. We talk a little bit in our intro each time about the depth and breadth of your involvement in the industry and your years of experience. And it's really great to see someone like you giving back so much to the industry and to be recognized for that is just a great honor. So congratulations, Greg.

Greg Hlavaty: Yeah, I appreciate that.

Karen Edwards: As I mentioned, today's episode is going to talk about restoring metal roofs, because they're a different animal, right? They're kind of unique in themselves and bring with them some different challenges. We chatted a little bit beforehand and you were giving me some comparisons about metal roofs being very similar to some other roofing materials. Maybe you could start there and talk about how they're different?

Greg Hlavaty: Yep. And my perspective on this is I don't know that it's unique, because there's other people, I'm sure that understand this. But in discussing this with some of the members at the RCMA meeting talking about metal roofs and some of the challenges. And that is that what we think of in our commercial roofing industry, a roof is usually a membrane. It's usually a hot asphalt roof, a modified bitumen, a single ply membrane, various PVC, PDM, all those things. And most of those roofs are a sealed roof from edge to edge of the roof. It's a watertight roof. A metal roof is actually more in the category of a residential roof. It is a shingle roof. And to understand that, you have to understand these are big metal panels. Just like asphalt shingles, wood shakes, wood shingles, concrete and clay tile. One shingle on a slope, they almost always have to be on a slope of some sort, they shed water from one panel to the next, whether it's an asphalt shingle, a clay tile, or a metal panel.

These are metal panels. One sheds vertically down the roof to the next panel below it, and then there's usually an overlap onto the next panel. It could be anywhere from 24 inches to 48 inches wide depending on the profile of that metal roof. And there are dozens, if not hundreds of profiles of metal roofs, meaning they're standing seam, there's double standing seam, there's butler building. There's roofs that are crimped at the top of the rise. There's hidden fasteners. But there's usually one thing in common, and that is that there's water channel that runs from the top of the roof down to the bottom, and each time it comes to the end of that panel, it sheds to the next one.

And it relies on that overlap and shedding to keep that roof watertight and keep water from intruding. And when they're new, there are fasteners that are sealed with rubber grommets or many of them have hidden fasteners underneath the caps, the high ridges there, those are usually more expensive, but a better roof where the fasteners are hidden. So as they get older, the rubber washers wear out, or butyl whatever they're made from. Some of them have gaskets at different places that dry up and wear out. And a metal roof, when it's new, is a great way to go for a large, usually in warehousing and commercial industrial buildings. We see them a lot in... less on the West Coast than we do in the south and on the east, where they're used heavily in industrial buildings and what have you, but there's still plenty of them all around the country.

And as they get older, they start leaking through those screw holes, through the fasteners, through people walking on them and crimping the metal between joists that puts a bend in the metal where that holds water. And some of them don't have enough of an overlap there. Less expensive metal roofs just overlap only a couple of inches where the better ones have a double overlap, over two ridges. So there's no way water can run sideways and get in.

So when a metal roof does start aging and starts leaking, right away, the building owner usually goes to a roofing contractor and they don't always go to a metal roofing contractor, they go to commercial roofing contractors. And what we're asked to do as a manufacturer and as a contractor to seal that roof up is to convert. And this is where people kind of lose sight of what's happening. We are converting a tile roof, metal tile roof into a membrane roof, which means that now we're going to seal every single seam vertically and horizontally so that there's absolutely no way a water can get into that, which means we have thousands, if not tens of thousands of feet of seam sealing to do and screw heads to do. It's a daunting task to put a good metal roof system on.

Karen Edwards: Sure. And I think about that now, and I'm envisioning the photos that I've seen of metal roofs being restored, and you do have those strips of sometimes fabric. Talk about what a contractor, how they properly seal those seams and the fasteners. What do they need to do?

Greg Hlavaty: Every manufacturer may have a little slightly different way of attacking it. But one of the things, the other challenge you have with metal is that it has a great coefficient of expansion and contraction. When it heats up, it expands more than an average roof, like a concrete tile or something like that. And it shrinks more when it's cold, which means there's movement. There's always movement. That metal roof is almost, I always... it's almost like a living animal. It breathes. If there's water, air pressure that comes into the building through big open doors, like if it's a big warehouse and the wind blows in and it makes pressure that pushes the metal out. If it's hot during the day and cold at night, like spring and summer and fall in some of the regions, that makes that expand and contract and one piece of metal slides over the next. And now we're asked to seal those properly and take in all that expansion and contraction and not tear at those seams.

So one of the things I'll say, if you're a building owner that has a metal roof and they want to know what to do about it, the very first thing you want to look at is a contractor that knows what he's doing. Because as a manufacturer, I can make the best materials on the planet or any other good manufacturer sealing systems. But what makes that roof work is that contractors' diligence to attack tens of thousands of feet of seams and sealing and getting the right amount on those. Some people use just caulking. We use a tape, an overlap tape with an elastomeric flashing compound that will take the expansion and contraction. And so somebody that knows what they're doing in applying that roof, that contractor is key to the successful roof more so I think than in any other of our disciplines. We can help them put a system over a BUR roof in a few short, day or two.

In a metal roof, it takes a lot of experience and knowing how to flash the different types of things. Where you don't flash. Some metal roofs have little bars that hold each lap down made out of stainless steel, and they have little weep holes in them that allows the water to run underneath. And you don't seal over those. If you do, then it doesn't shed water. You need to know the configurations of these metal roofs and how to attack each one differently. And if they're not attacked properly, you can create more leaks in a roof by doing an improper sealing than the leaks that were there before.

Karen Edwards: Wow. So you're not even restoring it or fixing the problem, you're creating more headaches for that-

Greg Hlavaty: Because many of them, they attack the horizontal overlaps that run across the width of the building, because the ones that are most visible. There's a vertical overlap all the way, and those overlap over a high ridge usually. And a lot of times they don't attack those. What they forget is that when you do the horizontals and that water runs down to the bottom of each panel, it expects to run down onto the next panel. And if the vertical overlap is not sealed and water gets behind a little bit, not enough to leak, but like in any, on an asphalt shingle or a tile roof or anything, if you lifted that up after a rain, it would be wet underneath the side laps. There was water that runs half an inch or an inch. But it runs out at the bottom at the channel and runs onto the next panel below it.

But if you seal the horizontal laps, the metal roof, and you don't seal the vertical ones, you've just damned the bottom of it. The water runs down like it's supposed to, it gets down there and you say, there's no more place for you to run out if there's a little bit of water behind the vertical laps. So in those cases, then the water runs horizontally. And part of that horizontal is back into the building. So I've seen many roofs where they, "Well, we sealed all the horizontal seams and now we have 100 leaks." Well, that's because you are not letting the water out. You got to go back and you got to seal every seam.

Karen Edwards: Wow.

Greg Hlavaty: And then follow up is a big thing too.

Karen Edwards: Right. So after they've sealed, made these seals, we think we've got it. When you're saying follow up, is that let's check back in a month, make sure everything's okay for-

Greg Hlavaty: A month, a year and a couple of years that roof is still moving. And you may think you got everything. And it looks great, because you've just... after you got through, you put a thermal reflective coating on it. One of our acrylics in our case. There's other types that some other manufacturers use. But we put a thermal reflective, which stops some of that expansion, contraction because it cools it off during the day, so it doesn't have to expand as much. But nevertheless, there is movement in that metal building. That's the way they're built. That's the way the structure's built. So you may not see where a seam you thought you had it attached and it pour a little bit, or it was light at one spot because there's thousands and thousands of feet to do on a metal roof.

And it's key to go back the first year, a month is a good idea, but the first year, the second year. And a metal roof should be under a service contract because again, no matter how good of a sealing you do, if that thing moves more than the membrane can take, metal, you put two pieces of metal directly against each other and then try to move them. Whatever you attach them with, I don't care, it's the best attachment, you can tear it at that seam. That's essentially less than almost zero inches where they attach. So you want to go back and you want to have a maintenance program. That's a big part of the metal roof. But they all want a 10-year, 15-year, or 20-year guarantee on the metal roof, the building owners do.

And the contractors are happy to sell it to them because they come to me and say, "Do you have a 10 or 15 or 20-year warranty?" Yeah, we do. But there's more to it than the warranty I give. It's the maintenance of that roof that keeps that warranty intact, and whether that roof is deserving of it. There are some metal roofs that are just not deserving of a warranty, and we have one up in Northern California. Our field specialist, Tim Ford's going up there to look at it in question whether that roof is good enough to receive a system and a warranty of the years they want.

So they should always be looked at if there's question about... if you've got a really good contractor that you know, knows what he's doing and he's out looking at a roof and he can report back to you, "Hey, I looked at this roof. It's in pretty good shape. I know what I can do and I can get it on." Well, great, you can trust your contractor. But if it's a new contractor or you are not sure about it, have one of your field people look at that roof and make sure it's something you want to warranty because metal roofs, in their golden years, can be a real handful to keep water tight.

So as I say, we're converting that shingle roof into a membrane. And in doing that, it's a challenging, no matter what materials you use. Some manufacturer may say, "I have better materials. I have this and that." They're all underneath the same stresses that we are. And that's the expansion, traction of the metal, the heating, movement of those metal panels. They're all similar.

Karen Edwards: This podcast is brought to you by AskARoofer and Western Colloid Fluid Applied Roofing. When you're looking for answers for your roof, what better place than askaroofer.com. If you are looking for answers on restoring your commercial, industrial or low slope roof, look no further than Western Colloid. For over 50 years, they have been bringing old roofs, new life. Together, we're helping contractors, building owners, property managers, architects, engineers and consultants choose the best commercial roofing system. Find Western Colloid today on askaroofer.com.

So not every metal roof, as you mentioned, is going to be a candidate for that. And it sounds like that's really, really important to find that out ahead of time. And then, you keep saying about the contractor's experience. But if there is a contractor, maybe he's been working with this building owner for five or seven years, they've got a relationship established and he goes, "I really want you to do this for me." What kind of support then do you offer the contractor? Because this whole conversation's kind of intimidating if I'm a contractor that didn't do this before. So tell me a little bit about that.

Greg Hlavaty: You're right. And they're not going to have experience until they have experience. And that's where our field support is. We have several people that are out in the field every day of every week, working with contractors and in place on the roof, maybe as part of the crew and teaching. And we do that regularly. The worst case is when they go up and attack a roof, we don't know about it, and all of a sudden we get an email, "Hey, I finished this roof. I used your materials and here's the warranty application." And that happens quite often, after the fact. And oftentimes, that roof can look good. We can issue a warranty, but we don't know what's underneath it. And that's something that building owners can be frustrated about in the warranties is that, well, I have a warranty right here from you. And if this wasn't done right, you said it was because you gave me a warranty.

Well, we said, because everything we know about it appeared to be done. But once you get a coating on that roof, you've buried everything you've done. Without scraping up everything, it's hard to tell what was on that roof. And if later on you find out there was some improper application, there can be some liability there. So they want to be careful when they're working with a contractor to get somebody that knows what they're doing and if they don't, get us involved so our field tech people can work with them and head them down the right path.

Karen Edwards: Yeah, I think it would be really important to take photographs, right? Because from before the start, during the application and when complete, because then maybe you didn't see the roof, but there is photo evidence of maybe the condition or the job that was done. So yeah, building owners, definitely make sure your contractor's sharing job photos with you throughout the entire process.

Greg Hlavaty: There's other things that come in play with metal roofs is corrosion. Steel roofs, they have rust. We, like other manufacturers, have a rust inhibiting primer. Sometimes the rust is so bad, just the rust inhibiting primer isn't enough. They really have to wire brush it, remove all live rust, get that off and then put a rust primer on. Other things are what kind of a surface is on that roof originally because it could be anything from galvanized steel, which is, that isn't corroded too bad, is fairly easy to go over up to Kynar. And Kynar is a type of coating that is put on metal in the factory. And Kynar is a really good product. It's a more expensive surfacing for metal roofs. You pay more for it, and it weathers longer. But also, nothing sticks to Kynar. It's a little bit like silicone in that things don't like to stick to it.

So we have a special primer just designed to stick to Kynar. And sometimes you know that you have Kynar and sometimes building owners don't know. It's already passed through two different hands and they're not sure. So that can be an issue. You might want to do a pull test to see if your coatings are sticking to that enamel, what you thought was enamel. And it really isn't an enamel, it's a Kynar finish. But most of them are not. But there are plenty out there, but it's something to be aware of. The design of the metal has a lot to do with it too, because regular corrugated metal, which just has low, everybody's pretty familiar with a Quonset Hut type corrugated metal, and you'll just overlap one overlap over the next.

Some of the better installations put two overlaps on, they go over two panels and those are done better. And when they overlap on the next panel below, they don't just go two or three inches, they go five or six. But if you're trying to cut corners and make it less expensive, they'll put it on with less, all the way up to a butler type building, and several of them where they actually crimp the metal up at the top of the ridge and it's crimped up there and the panel runs all the way from the ridge to the eave of the building, which means there are no overlaps.

Those kind of roofs are very... basically they just get a coating. They get sealing around roof vents and roof jacks and anywhere there's a protrusion coming out of the building. But other than that, just a good coating because those, you pay more for those buildings up front, but the reason you do is because they last longer. Those seams don't need to be resealed. They're crimped at the top of that ridge. There's no way for water to get in. So there's a lot of factors that come into a metal roof in the design of it and how you attack it when it becomes aged.

Karen Edwards: Any special considerations for tying that roof into the walls or other parts of the building? What should contractors and building owners be thinking about there?

Greg Hlavaty: Yeah, I'm glad you pointed that out. You're exactly right. There are considerations. And there's two that are a factor. One is a wall where a metal wall come down on a lower metal roof. And usually if they're done properly, there's a metal flange or flashing that runs out over the metal below should be six inches or more. And then it runs up behind the metal panel coming down that wall at least six inches. But a good one goes up 12 or more inches. A lot of them are just three and three. Well, that's not very much overlap. So a lot of times those, you actually seal that seam with the flashing compound and fabric or other forms of flashing materials. But in our case, it would be a rubberized flashing compound. But if they're properly done, and that's where in the beginning, how expensive of a metal roof was this? Was done with all the good bells and whistles or did they cut corners and use very small flashings?

The other is gutters, both on the exterior... and many metal roofs have interior gutters where you've seen a slope and it goes down into a gutter. And that's where the leaks really happen. What happens is on heavy rains, those gutters fill up. They don't keep the downspouts cleaned out. Those gutters fill up. It doesn't matter how well your roof is sealed, once they fill to the top of that gutter, it's not sealed to the metal roof. There's just a flange at the edge of the gutter. It goes up, fills over the top and just spills into the building. A proper metal fabrication of a gutter runs up at least eight inches, but should go 12 or more inches underneath the metal panel when it comes down. So if it fills up with water, it can't just run up an inch or two and then into the building. But most of them don't go enough.

So that means now they got to seal that gutter onto this weird shaped piece of metal that's just laying on top of the gutter. How do we seal that off? Some of them, they used to have rubber pieces that fit underneath that you kind of pushed underneath there and those dry out and crack. So that's a heavy sealing proposition, or a foam where they use canisters of foam to squirt underneath there to try to seal that off because you can do the best job you want on the metal part of it. Those gutters are very tough.

And the next thing is, does that gutter have a big enough downspout? Because a lot of times they'll only put a two inch or three inch downspout and it's shedding water from 500 squares of metal roof down onto this gutter. And that's a lot of water on a heavy rain.

Karen Edwards: Sure is.

Greg Hlavaty: And two or three or three inch downspouts don't handle it. So those should have large, four to six inch downspouts, where all that water can evacuate that gutter and drain so it doesn't fill up to the top. So there's a lot of factors to look at when somebody's attacking a metal roof and the entire building and structure.

Karen Edwards: Right. So my last question, and maybe this is handled through roof penetration vents, but I was thinking ventilation for the building because metal roofs need to breathe as well. So what things should they be thinking about in terms of restoring that roof and making sure you don't screw up the ventilation?

Greg Hlavaty: So metal roofs are notorious... condensation has become a big buzzword in the roofing industry since cool roofs came around. We started cooling off roofs and bringing them down where the interior vapor can condense on the underside of a membrane or the underside of a deck, roof deck or whatever. And metal roofs have always had an issue with condensation. We were called out to several metal buildings in the Central Valley. They say, "Our roof's leaking like crazy." And we go out there and say, "Well, that's unusual. It hasn't rained in four months." Well, that's because they have moisture inside the building that condenses up on that roof. And if it's a reflective roof, it can condense even more. So ventilation is... Many parts of the world, you go to Europe and that, ventilation is a big part of any cool environment. You've got to vent, inside air and outside air need to mix or you need to extract inside air where vapor can build up.

And the other part of ventilation and a metal roof is air pressure. We talked about that. If you have large doors that face where wind blows in, it can expand that metal roof from the air pressure coming in through doors, especially in hangars, airplane hangars. We did some Air Force hangars that they had a real problem with great big doors that opened up and the wind blew in and it would make that roof expand. I don't know how much, but several inches over from end to end/ and that put stress on that roof. So at the top of that, they put ventilation all along the top. So when air came in, the pressure was released out the top.

And a good metal roof has a ventilation at the top, so hot air can rise and go out. Some of it is motorized. Some of them use the rotary wind-driven turbines that we've all seen. But all those things are a factor that should be addressed on a metal roof, because now we're really sealing it in once we turn that into a membrane. So ventilation is something that maybe another expert might be called in for if you don't have enough knowledge. We're not ventilation experts as a roof coating manufacturer, but some building owners and some contractors either have somebody they work with that can advise on what kind of ventilation should be used.

Karen Edwards: Yeah. That ventilation is key to the performance of the entire roofing system. And it's a little hard to understand as well. So I definitely call in the experts on that area. But wow. So Greg, this has been really eyeopening and enlightening for me because I tend to think of, oh yeah, we're just going to put a coating on the metal roof. But there's so many factors and variables that go into that consideration. So as building owners, please, please have these conversations with your contractors or even the manufacturer who can connect you with a contractor that is able to help you with your situation. Wow. Really interesting stuff. Is there anything I forgot to ask you? I think we covered most of the bases.

Greg Hlavaty: One thing I'll point out, sometimes they don't need to seal a metal roof. It's working, but it's hot. We would like to get it cooler. So they want to put a white reflective coating on it, an energy, reflecting coating. And that is a really valid, because metal conducts heat. There's very little, if any, emissivity in the small enamel coating that's on a metal roof. If it's a light color, it might have some solar reflectivity, but no emissivity that gives off whatever. Whatever heat it gains, it passes right through the interior of the building. We know metal conducts electricity, it conducts heat, it conducts a lot of things very easily. So we want to get a nice white, in our case, acrylic coating on a metal roof, but it's not leaking.

And there's a point to this and that is, if that's what you're looking for, then great, do that. But again, have a good contractor because what you don't want to do if it's already working and your metal roof is shedding the way it should one panel to the next, you don't want to put on a coating that seals some seams when you spray it and doesn't seam others. And you start damming the edges of the metal roofs. You want to put on nice light coats of coating in two or three passes so it doesn't build up a heavy buildup and seals off all those edges, if all you're trying to do is put a reflective coating on there. So now we're trying to not seal the seams. We're doing the opposite.

Karen Edwards: Yeah. You're just trying to lighten it up.

Greg Hlavaty: Yeah. Yeah.

Karen Edwards: Wow. Wow. Interesting. Great information, Greg. Thank you so much for being on this episode today. And I just want to remind everyone that we want to answer your questions and you can submit questions to us on askaroofer.com. You can submit them on westerncolloid.com. And if we answer your question on an upcoming episode, we'll send you a gift. So please let us know what you want to know, and we'll do our best to give you those answers. And next month we are going to talk about restoring spray polyurethane foam roofing. So be sure to stay tuned for that episode. And remember, you can listen to the podcast on any of your favorite podcast platforms, as well as askaroofer.com and westerncolloid.com. Greg, thank you so much for being here today. It was so fun to learn all about metal roof restoration.