TPO and PVC membrane roofs are incredible roof systems. They are what we call a reflective roof system and known as a "Roof-over". In this article we'll talk about TPO roof cleaning and how its done. This is because insulation (in most cases 2-inch polystyrene board) is placed over your existing roof surface and then the membrane, which is white, shiny, and reflective is then placed over that insulation and then heat fused together and terminated at the edges to create a watertight seal. When done the roof surface is essentially one piece from edge to edge.
In the picture above is a TPO membrane roof that is 13 years old. We have been caring for this roof for 5 years now just doing annual cleanings and
inspections. When we first came upon this roof it was dirty and neglected, as seen here and had a couple punctures from debris. This was approximately 3 years of neglect, and the debris most likely from the last hurricane.
The first step in cleaning your TPO roof is always going to be an inspection to make sure that it is cleanable to begin with. Inspecting the membrane itself to make sure that it is not frayed or compromised. Inspecting the seams and protrusions like solar tubes, sky lights and vents to make sure that they are "welded" properly and note any issues.
Before we get into the cleaning process let's look at some of these problems so that we can define them visually.
This picture is of an open weld. This is caused by improper technique during installation. It is an active leak, even though the membrane should always overlap downwards it still leaks under the membrane by a process called wicking. These are dangerous leaks for the roof system because they generally aren't large enough of a leak to cause damage to the sub roof and penetrate all the way to the ceiling. These generally go unnoticed but they are definitely doing damage to the roof system itself. Depending on where they are located, they cause damage to the insulating board and rust out the steel plates that hold down the membranes "runs" at the overlap. They also can cause the perimeter wood to rot. Annually inspecting the roof means when these welds pop, they are caught early, and the solution is pretty easy with the right tools and knowhow. It's just a matter of hooking up the leister heat gun and rewelding the areas that are open, probing with a pick and welding any problem spots.
This next picture is popped termination bar. This is a common issue with older roofs, especially the older systems that used the 1x4 perimeter wood and insulation. Today we use 2 inches. This also, is an issue that can be caused by improper installation. Today we use special grommeted screws and torque them just to the right degree. Alot of times in the past these screws were over torqued causing them to be slightly stripped in the wood. Over time this creates a small leak into the screw hole as the roof contracts and expands daily. We see this when we tear these sections off, each screw will have a small, rotted section right around the screw. At times it rots the whole board out. This is super dangerous for your roof because that bar is securing your whole roof to the edge of the home. When heavy wind hits a roof with popped bar it will take the whole edge and tear it right off the home. We solve this in different ways depending on the cause and the severity of the problem. At minimal we can sometimes seal the old screw holes with OSI and the screw the bar back down with new grommeted screws. Sometimes we need to replace the perimeter wood itself if it is too badly rotted it will of course not hold any screws. In this scenario we can do what we call a "cut-in". This means we unbar the roof edge in question, remove and replace the compromised wood, cut back the membrane approximately 1 foot and add new membrane up under the existing membrane for six inches, clip it in, rebar and reweld. Essentially this gives the roof a new edge. Most companies won't consider this because they want to sell you a whole roof. More roof, more money. Most times the "field" as we call it is in perfect shape and the edge is the only problem. We believe in solving problems.
This picture here is from flying debris. Just punctures from objects that were flung airborne during a hurricane. Sometimes these can be dropped tools during installation, and even factory defects or careless shipping procedures. Whatever the cause they are an active leak on your roof and a little hole like that will amaze you to how much water it will allow to ingress. Again, with this roof system it is an easy fix with the right tools and knowhow. There are different types of manufacturers of membranes. So the first problem is identifying and matching the product. Most membranes will only weld to themselves. they don't like to adhere properly to others. They don't play nice with others! Once the type is known it's really just cutting the right size patch, making sure the edges are rounded and not corners, and then welding them over the wholes with the leister heat gun. Problem solved good as new.
Any protrusion on your roof is a potential problem. We already addressed open welds. These aren't just a problem at the run seams, they are also at each vent, solar tube and skylight. So, these need to be addressed as well and made sure they are solid. This picture here is of a really old skylight lid that has been damaged over time by the elements. UV damage, possibly chemicals that weren't rinsed properly, and improper installation are a few of the reasons why this can happen. These cracks are obvious leaks and will quickly do damage to your sub roof and ceilings. These are not repairable but are easily replaceable. Generally, the base is good it's just that the lid itself has failed. We measure the size of the curb here and order a new lid and install it. Not only does that solve the leak, most people are astounded at the new "view" that they have again and the amount of light that they get back once more! The dulling happens slow slowly over such a span of time most homeowners don't even realise the loss until they are refreshed.
Now this is why we maintenance and clean TPO and PVC roofs, and the reason for this article to begin with. This is TPO that has been neglected. The surface is brittle, and cracking and the reinforced mesh is exposed and showing through. This roof is shot and needs replaced. Nothing will weld to it, all of its essential oils and plasticity are gone. I have seen 40-year-old TPO roofs that are in amazing shape and 20-year-old roofs that are failing. It literally just comes down to maintenance.
I have a client in palm harbor who is 96 years old. He has a 43-year-old TPO roof on his home and he personally cleaned it himself every year since it was installed up until 4 years ago when he finally decided that he didn't need to be on a ladder anymore. 92 years old! 4 years ago, he hired us to continue caring for his roof. This roof is in amazing shape, no cracking, no brittleness, the only issue it has had is some popped bar and we were able to easily solve that. On the contrary I have worked on numerous roofs not even half its age that were neglected and needed replaced like the one in this picture. The kicker is that these membranes have evolved and gotten better over the years. The moral to the story is that maintenance is the difference between a lifetime roof or purchasing another whole roof down the line.
This roof is way past due for a cleaning. My rule is you never want to see black streaks on a TPO roof. Our cleaning process removes all that it can and restores roofs to their best state, however as I am cleaning and when I'm done, I can tell where the damage has taken place. It isn't very visible, but this slight yellow staining will be deep into the membrane and that doesn't come out. That yellowing is a warning sign.
Now here is the cleaning process. Finally, I know! Each roof is different, that is the first thing. Some are neglected like this one and some just have a little organics and some fall-out and maybe a little oxidation. The percent of the solution will differ accordingly. The mix will range from 1.5 % to 2.3 % depending on that level of filth present. You should never apply a stronger mix than 2.3 %.
Our solution is mixed with a proportioner that combines sodium hypochlorite diluted to the specs above, depending on the roof, and a surfactant. We use a product called Slo-Mo, and EBC glide combined. (Once in a while around airports we need a light degreaser as well, but not often.) We apply this mix onto the surface of the roof evenly with a dedicated soft wash system, but you can mix this in a pump sprayer and apply that way if you wanted for some reason to do it on your own. Depending on the heat and direct sunlight we let this dwell between 15 to 30 minutes, misting it as necessary to keep it from drying. At this point the organics (mold, mildew, pollen, lichen, etc.) are dead. This is where the problem for the do it yourselfer comes in. We have a special machine, it's a surface cleaner that we customized for TPO roof cleaning. This surface cleaner is modified to allow the flow of water at a psi of 1100 and max flow. This allows us to run it over every inch of the roof surface and agitate the contaminants off, leaving the surface clean, white, and shiny. It removes the oxidized film as we go as well. ( DO NOT USE A STORE-BOUGHT SURFACE CLEANER, YOU WILL DAMAGE YOUR ROOF.) You could achieve semi results by brushing the entire roof with a stiff broom, but not to the level our machine cleans it. It is simply the most efficient best way. This is then followed by a rinse from top to bottom and then cleaning out the gutters and flushing them as well.
This is the roof after cleaning. It looks amazing right. What you can't discern from the picture is that slight yellow deep staining I spoke about earlier in the article. Here and there on the roof where some of those black streaks were, is now a faint stain only visible when you are right there on it. This picture is blown up and if you try, you can barely see what I am talking about. While it looks super minor, these spots if left untreated will cause the roof to fail. Even now, that area of roof is less than the healthy parts of the roof. We are only able to minimize it. Don't allow this to happen to your roof. That is the key! Routine maintenance wins the day!
Well hopefully this article was helpful and informative, if you have any questions or wish to learn more about your roof give us a call, we would be happy and honored to help you out!
CLEAN 2 PRESERVE llc
Clean2preserv.com
Clean2preserv@gmail.com
727-203-6371
It' amazing the knowledge you have! You explain it in such detail, explaining the importance of proper roof and gutter care! Thank you for taking the time to tell us the right way to have it done the right way!!