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Five Commercial Flat Roof Systems Explained – Watch Video

This Video Explains about the Three roofing systems – TPO. EPDM and Modified Bitumen Torch Down

Five Commonly Used Flat Roof Systems 

There are 5 types of commercial flat roofing systems commonly installed:

  • Built- Up Roof (BUR) also known as the “Hot-Tar-and-Gravel” Roof System
  • Metal Panel Roof System
  • *2 Ply Modified Bitumen Torch Down Rubber Roof System
  • Single-ply membranes such as TPO, PVC and EPDM Systems
  • Spray polyurethane foam-based Roof System.

*Commercial Roof USA specializes in the installation of 2 Ply Modified Bitumen Torch Down Rubber Roof System.

This is a BUR system also known as a Tar and Gravel roof.

Built-Up Roof Systems (BUR)

The BUR system has been in use in the U.S. for over a 100 years. It is commonly referred to as a “Hot-Tar-and-Gravel” Roof System. These roofs are composed of layers of saturated asphalt paper and moped down hot liquid coal tar or asphalt. Saturated paper is layered in a criss-cross pattern, and depending on the contractor, as many as 12 layers of paper and coal tar or asphalt can be used during the installation.

Coal tar or asphalt is heated in a kettle with propane gas and pumped up to the roof top. Hot tar is spread over the work surface with a mop or squeegee, and the felt paper is rolled out over it.

Asphalt is a petroleum product refined from crude oil and coal tar comes from the distillation of coal. Either way, the coal tar or asphalt is the adhesive, that when combined with many layers of felt paper, forms a thick membrane that becomes the roof.

After the membrane has been built-up, a thin layer of coal tar or asphalt is mopped over the entire roof and aggregate stone of 1/2” is spread over the entire membrane. This stone is used to protect the roof from harmful UV rays.

The “Build Up” has “Come Down”

The BUR roofing system can last many decades, but beyond that, there will be a certain amount of degradation. Petroleum based products will become dry and brittle and start to crack, due to evaporation, causing leaks.

The BUR roofing system is expensive to install, due to the labor and materials involved. These roofs have been known to last for over 50 years, because of the multiple layer “build up.”  Some of them have had as many as 15 -20 layers of paper and tar, however, we have also seen that some contractors would “come down” with the number of layers, to as many as 5 and to as few as 3.

Metal Panel Roof Systems

The Structural Metal Panel Roof System is a type of metal roof system used for a low slope application. It is common to see metal panel roofs over warehouses and factories. The metal panels can span up to 4 ft., from rafter to rafter and can support the weight of a person. A special sealant is used between seams and overlapping joints to prevent water from entering. Neoprene washers are used where bolts fasten the metal roof to the metal rafters. These metal panels are excellent water barriers and will prevent water from leaking through when correctly installed. This type of roof can last for 40 to 50 years, when properly maintained.

Metal roofs systems can be repaired.

Modified Bitumen Membranes

The Modified Bitumen Torch Down Rubber Roof System (MB) was developed by the Italians in the 1960s and made its way to the U.S. by the late 1970s. The rubber membrane is made of reinforced fabrics covered with asphalt, which consists of modifiers that give the asphalt its elastic properties on both sides. The modified asphalt is manufactured in widths of 36″. Because of the rubberized technology, these membranes are referred to as rubber roofs or rubber membranes.

There are 2 Types of MB Rubber Roof Membranes:

APP – is a Modified Bitumen membrane that is fully torched down to the fiber base, and the torch is also used on the seams, hence the name – Torch Down Membrane.

SBS – is a Modified Bitumen membrane that uses cold or hot mopping tar or asphalt adhesives. Some SBS membranes are self adhering; the backing is very sticky, and will adhere to the surface it is rolled onto.

The MB membranes have 3 types of surfaces: smooth surface, mineral surface, and a foil laminate surface. The minerals of the surface have been coated with a ceramic material that protect the rubber against harmful UV rays.

The MB roof system is typically installed as a single-ply system, however, we specialize in a 2-ply system to extend the roof life to 40 years or more. We have come to specialize in this roofing system for many reasons, but the most important one, is in terms of maintenance, because the Modified 2 Ply Bitumen Torch Down Rubber Roof System, needs minimal to none.

Single-Ply Membranes: EPM, TPO, and PVC

EPDM, TPO, and PVC are single ply synthetic membranes, and are manufactured in wide sheets. These membranes are very thin and come in rolls from 8 – 20 feet widths.

Adhesives are used to adhere these membranes to the properly cleaned substrate. If the substrate is not properly prepared; removal of dust and particles, according to manufacturer’s instructions, the adherence is compromised, and the life of the roof is reduced.

EPDM is made from 2 compounds that are derived from oil and natural gas and the seams are glued together with a liquid adhesive that has been reformulated 4 different times. Currently, as a remedy, a new self-adhering cover tape is placed over the seams. These membranes are not well protected from harmful UV rays and are prone to degradation.

The Image below is a Modified Bitumen Torch Down Rubber Membrane with Embedded Ceramic Granules for UV Protection

The image is an example of a 2 Ply Modified Bitumen Torch Down Rubber Roof System.

The Image Below is a White TPO Vinyl Roof with Little UV Protection.

A White TPO Vinyl Roof with Little UV Protection.
3D Video demonstrating the best drain and strainer system
Skylight flashing explained and corrected
Metal roof Repair - easy and permanently

Different flat roof systems explained

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Metal Roof Repair: Leak Causes and Fixes – Watch Video

This video explains why it’s not a good idea to coat a metal roof with silicone spray.

This video demonstrates how we went about to save a metal roof.

Metal Roofs That Leak: Repair Options Video Transcription

Almost all metal roofs can be saved

Hi, I’m Erik with Commercial Roof USA. I’m here on a commercial roof today and this is a metal roof and um now the metal roof was starting to show its age and the people decided they needed to do something about so they went with a silicone coating. Now, the, here’s the exact reason why we don’t recommend putting a coating on this. Now they put a coating and it looks pretty nice.

If you look everywhere, looks uniform. It looks very nice, but the issue come three, four, five years later and this is exactly what happens, this is the fifth year and this is what happens. You get tiny holes in the silicone and then it holds the water and then starts rusting through and here’s a perfect example right here where we opened it up. And like you can see it just folds back and look how wet it is in here and look at all this rust you see that? it’s starting to go through. I can feel it here. There’s water sitting here right now. And the problem is it doesn’t get a chance to evaporate; it doesn’t go away.

So, it rusts through even more. Look how look at the puddling. It goes all the way down it there. Alright, let me show you another example. This is how it looks like before we rip it open. Right here, you can see, that’s just a pin prick, like a little hole here, you can see it’s crunchy in here because that’s where all the rust is. So, there are several issues with the silicone. Another problem is when you get to the joints and I’ll show you that in just a minute.

Here’s another issue. Right here, it’s impossible to get the silicone to set properly right here where the rise in the lip is and you can see that’s why we can’t recommend coatings because what it does it just basically just holds water there and then with the heat from the sun and with the moisture there it’s gonna go through even quicker.

You would have been better off without anything on this roof. We actually would have preferred it that way, cause now when you have to repair, now what we have to do is we have to come in here, we have to grind off all this, uh the silicone, which is a big mess, and then we have to get the rust off of there with even more problems and fix the holes that the rust has made and then we can start patching it.

So, this has become a bigger problem because they decided to coat it instead of trying to fix the actual problem. Here we’ve done one of our patches already. The process that we do is first we have to get the silicone off, and then we have to grind down the metal because of all the rust that was on there and fix the holes, and then what we did is we put down our adhesives which you can see here on the sides, and then we put down our modified bitumen membrane.

Now the reason we use this and why this will work, where the silicone did not, because a membrane won’t go through like a silicone will. The silicone, as you can see when I showed you over there, you know just a simple small little pin prick of a hole caused the problem. This nothing is gonna pierce this, even if it did there’s an adhesive under here and the water can’t get underneath this. It can stay like this for the next twenty to thirty years. Nothing will happen.

Silicone breaks up and just the sheer thickness of our material also is gonna prevent anything from going through. The silicone, I don’t even know, I don’t know how thick that is, but you can see, let me grab a piece here. You can see how thin that is. That’s gonna get eaten up by UV, UV rays in no time. This, our membrane already has UV protection and is 3/8” of an inch thick as well as having adhesive, petroleum based adhesive underneath that which adheres to metal very well.

The Growth of the Metal Roof Industry

Based on the research conducted by Metal Building Manufacturers Association (MBMA), pre-engineered metal buildings constitute over half of all the latest, low-rise one and two-story, non- residential structures in the U. S. Based on this huge quantity of constructions with metal roofs, there will be a need for repairs in the near future.

Causes of Metal Roof Leaks

The expansion and contraction, of metal roof structures, is caused by temperature changes. The stress of movement to the screws and neoprene washers, against metal panels, leads to leaks when the torque tolerance weakens. Another cause of leaks can be found at the end and side laps of metal panels, where the initial butyl tape or caulk seals, shrinks and creates gaps. A more obvious cause of leaks comes from the accumulation of standing water which leads to rust and eventually corrosion.

To learn more about coating product properties as well as see the additional usage applications, go to EonCoat learn more about the product properties as well as see  the additional usage applications. Our website also includes updated industry news and blog posts about protective coatings.

 

Repair Solutions

Silicone Spray 

There are a couple of methods that we have seen used to recover or repair a metal roof. One popular method is to spray the entire roof with a silicone coating, even though there are only a few areas that leak. Despite the surface preparation, the application of a primer, the fantastic appearance, and the cost effective claims, this type of coating only lasts 3-5 years. During this time, pinpricks and expansion and contraction cracks develop causing water to collect between the coating and the metal. This water accumulation is not detected until the the compromised area of the roof has rusted through.

Rubber Membrane

We have developed a method, of metal roof recovery, by using a technique that we perfected, from many years of installing flat roofs. It is relatively inexpensive and involves the combination of rubber membranes and adhesives. Repairing rusty metal with liquid or elastomer products is a challenge, because these materials do not stick to metal permanently. We have overcome this challenge by developing a method that attaches a rubber membrane to the metal with little surface preparation. The rubber not only adheres to the metal, but it also expands and contracts, where all other coatings have less elasticity and tend to crack, after only a few years. This method of repair is also cost effective because our repair technique extends the life of the roof significantly. It doesn’t matter how many leaks a roof has or how rusty it is, as long as it can be walked on, we can fix leaks with a rubber membrane, at a fraction of the cost for a replacement.

Beware of Temporary Fixes!

Every metal roof has its own challenges, but we’ve always had success repairing roofs that have had the fewest repair attempts. When those repair attempts include the use of silicone caulking or sealants, as a fix, the removal of such sealants becomes labor intensive. These materials are very difficult to remove from the metal to achieve the best bond for our materials.

Our Repairs Work

  1. We use a petroleum-based sealer and adhesive that adheres to metal even when it is rusted.
  2. Repairs with our method are less expensive than the costs of silicone or epoxy coatings.
  3. The rubber has embedded ceramic granules for protection against harmful UV rays.
  4. The rubber expands and contracts with the metal.

Metal roof recovery. We covered this entire metal roof with a rubber membrane.
This metal roof was covered with a Modified Bitumen Membrane and the life is extended to another 40 years

The image below shows that water cannot flow past objects freely, so the ponded water will cause the metal roof to develop rust.

The image below shows rust where standing water remained because it was not able to flow past the seam in the roof. 

The image below shows rust where water was standing because it was not able to flow past the seam in the roof.

Caulking to Repair a Metal Roof

Notice that in the image below, caulking is used to seal flashing, which is not a permanent repair.

Caulking is used to seal flashing. This is not a permanent repair.

Tar is Used to Repair Leaks around a Skylight on a Metal Roof

A common material used to repair leaks, around roof top units, on a metal roof, is tar.  This method is very temporary because the tar will dry out and crack very rapidly.

A common material used to repair water leaks, around roof top units, on a metal roof, is tar. This method is very temporary because the tar will dry out and crack very rapidly.

In the image below, we removed the old tar and cleaned the flashing around the skylight. It is important that old caulking and sealants be removed before our rubber membrane can be applied.

we removed the old tar and cleaned the flashing around the skylight. It is important that old caulking and sealants be removed before our rubber membrane can be applied.

After everything had been cleaned, we installed our rubber membrane with a special bonding agent. This type of repair will outlast any other sealant, caulking or tar. It covered all the seams and any area that had rusted through. The surface is now smooth and water can flow freely.

We installed the rubber flashing all around the skylight .

Pooling Water on a Metal Roof

Below is another example of the damage caused by ponded water. The tar around the vent pipe, has dried and cracked and began to leak. We repaired it by installing a rubber membrane around it.

Vent on Metal Roof.

The flashing around this vent stack was tarred. The tar eventually dried and cracked. After we removed the old tar and cleaned the metal surface, we installed our rubber flashing around the vent stack. This will last for many years to come.

The flashing around this vent stack was tarred. The tar eventually dried and cracked.

Rooftop Units on a Metal Roof

Whenever there are rooftop units like vents, skylights, or fans, the chances are that water will accumulate around the flashing, causing the metal to rust and increase the potential for leaks.

Temporary Repairs

Below is another example of a temporary repair using tar to seal open space around flashing. The tar dried and cracked and needed to be permanently repaired.

Repairs to Vent Pipe Flashing 

This is another example of a temporary repair using tar to seal open space around flashing. The tar finally dried and cracked and a permanent repair is needed.

temporary repair using tar to seal open space around the flashing. The tar finally dried and cracked and a permanent repair is needed.
The edging of a metal roof is also prone to leaks. The gutters and gutter hangers are fastened to the edge of the roof with screws.

Edging of a Metal Roof

The edging of a metal roof is prone to leaks. The gutters and gutter hangers are fastened to the edge of the roof with screws. Those screws and brackets sometimes loosen up and cause the roof to leak. We use the same rubber membrane to repair the edging.

The edging of a metal roof is also prone to leaks. The gutters and gutter hangers are fastened to the edge of the roof with screws.

We install a rubber membrane over roof joints, flashing and any areas where metal has corroded. This is the best solution for any metal roof.

This is the best solution for any metal roof. We install a rubber membrane over roof joints, flashing and any areas where the metal has rusted through.

Metal Roof Repairs and Roofing Conractors We benefit on Google if you write a comment on Metal Roof Repairs

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