Most adobe homes have “flat” roofs. This type of roof system requires the most maintenance and is the most likely to leak. Applying a premium elastomeric roof coating in regular intervals on these roofs is one of the best maintenance programs available. Though applying roof coatings is one of the easiest projects for the do-it-yourselfer, there are certain do’s and don’t you must be aware of in order to do the best job possible.
One of the most important considerations when tackling this job yourself is in the choice of the roof coatings themselves. There are many products on the market, and choosing the right one can be a daunting task. One piece of advice: don’t be lured into purchasing a roof coating just because the sticker price is low.
Not thoroughly pressure washing the roof before applying the elastomeric roof coating is another common do-it-yourselfer mistake. Flat roofs collect dirt and debris and must be cleaned prior to coating. To not do so is begging for the coating to fail. Caution! Improper pressure washing can damage your roof. High pressure jet spray can rip and tear into the roofing materials, and carelessness in directing the jet spray into crevices, cracks, tears, bubbles and other openings in your roof can cause flooding and mold growth on the inside of your home.
(Click on each of the above photos to enlarge the view.)
The above four “before and after” photos are remarkable. This was the most difficult and time consuming roof coating job Adobe Masters has ever done, taking almost five full days just to pressure wash it clean. We had to strip this old, peeling coating inch by inch with the pressure washer spray until most of the old coating was removed. The vast majority of our roofs only take a day or less to clean, so five days was extreme.
As you can see, this was a very large roof and it was a project that was far overdue for the homeowners, Mr. and Mrs. Bull. Like many people, the Bull’s did not pay too much attention to their roof, because like the old saying goes, “out of sight, out of mind.” Most of us don’t even think about our roofs until they leak.
Two of the skylights had to be replaced, and many of the areas of the roof that held ponding water had to have a polyester roofing fabric imbedded in these low spots to prevent the water from disintegrating the new elastomeric coating. Most people do not realize that even the best elastomeric roof coating is not intended to have rainwater simply sitting on top of it for days on end without having reinforcement added to it. Situations like that will destroy even the most expensive roof coating and the solution is to imbed the fabric system into these low spots in conjunction with the roof coating. Then, water can sit all day, every day for weeks on end, in these low areas and the water cannot penetrate into the coating and ultimately destroy it.
Adobe homes, for the most part, have flat (slightly pitched) roofs. Pressure washing them clean and applying premium roof coatings is another service we provide.
One service request I frequently receive from customers is for leaking roofs, usually after a heavy downpour. For the most part, these leaks are usually easy to locate and repair, but they can be challenging. Many people assume that if their leak is coming from a particular location in the house, like in the middle of their living room ceiling, that the source of the leak is directly overhead on the roof. This is not always the case; sometimes it takes real detective skills to locate these leaks.
An acquaintance of mine had a serious leak near the back end of her ranch style adobe home. She called a couple of roofing companies to give her an estimate of what they would charge to fix the leak. Both companies said she needed a new roof, each quoting her multiple thousands of dollars.
Thankfully, she remembered to call me and I went up on her roof. It was in better than average shape and certainly did not need to be replaced. But finding the source of her leak was not as easy as giving her the good news that her roof did not need to be torn off and another new one put on.
I find that many roofing companies are dishonest; they are usually in the business of putting on new roofs–not fixing old ones that still have many years of life left in them. Because these companies make their greatest overall profit by putting on new roofs, one can understand why they are so keen to tell customers they need new ones.
Adobe Masters is not a roofing company. We do not specialize in tearing off old roofs and putting new ones on. Neither myself nor the men who work with me are trained in this specialized area. But I am trained in roof repairs, and have spent decades in tracking down and repairing leaks. We also apply roofing membranes and coatings to preserve and prolong the life of roofs. Thus, my philosophy when it comes to roofs is much different than a roofing contractor: I’m looking at your roof through the lens of wanting to preserve and prolong it as opposed to looking at it and wanting to replace it. This is a great distinction that should not be overlooked.
I cannot remember all the houses I have looked at over the thirty plus years as a contractor where a roofing contractor has recommended that someone needs to replace their roof when they never actually had to. Some of these companies are wholly unethical and are intent on robbing people of their hard earned money by recommending a service that the customer does not need.
People who have “flat” roofs do have higher maintenance needs than people with very pitched roofs. I need to explain what I am referring to as a “flat” roof. These roofs are not actually flat, like what their name implies, but are slightly pitched so that when it rains, the pitch of the roof is such that the rainwater sheds off the ends of the home.
One of the problems with these flat roofs is that they are notorious for having areas where water ponds. There are usually areas on older homes where flat spots on the roofs, holding the rainwater, can be easily seen. Depending on the weather and humidity, these ponding areas can remain on a roof for days at a time before evaporating. This is where problems can develop.
The material that comprises a typical “rolled roofing” roof is not meant to have standing water sitting on top of it for extended periods of time. As these roofs age, cracks develop in various areas, oftentimes in the places where the water ponds. Water can percolate through these cracks, degrade the roofing material, and cause leaks.
This is why quality roof coatings are critical to the longevity of a flat roof. Adobe Masters, though primarily an adobe repair business, does a significant amount of roof coatings and repairs. When we work on a customer’s home to repair their adobe, we always work on top of the roof to reach needed areas of repair.
For example, certain sides of a chimney can only be reached by walking on the roof. There are also adobes that make up the inside parapets of many roofs; these can only be addressed by walking on the roof. Many deteriorated adobes which make up the last course of the adobes laid up by the masons can best be repaired from working on the roof.
When I come out to a customer’s home for an estimate, I always go up on the roof to both measure and inspect those adobes that cannot be seen from a simple walk around the structure. All this time on the roof provides me an excellent opportunity to inspect its condition. If there is work that needs to be done, I can give the customer a price break on this portion of the job if we do it in tandem with the adobe repair. This is because we are already there and can plan on working the two projects together to maximize our time and materials.
There have been times when I have explained to customers that have specifically called me out to inspect their adobe that their roof is in more need of immediate attention than their adobe. As a homeowner myself, I understand that our roofs are the number one protection from the elements. Thus, they demand our top priority as far as maintenance is concerned. You can certainly have severely damaged adobes that desperately need restoration, but these adobes usually don’t cause leaks into the home.
On the other hand, a severely deteriorated roof will eventually allow water to penetrate into the home and potentially cause severe damage, which is why a severely deteriorated roof takes priority over a severely deteriorated adobe.
When I attempted to track down and repair my friend’s leak, I was confronted with one of those few roofs where the source of the leak was not obvious. Again, most leaks are fairly easy to diagnose as to where the source of the water is entering into the home. If the leak is coming from a skylight, for example, a quick inspection of the skylight itself usually reveals the reason for the leak. It might be that the skylight dome is cracked, which would require replacement. Or, the metal flashing where the skylight frame lies on top of the roof may have it’s protective membrane separating, allowing water to seep in…a relatively quick and easy fix.
Another common area for leaks on flat roofs are in the area where the scuppers (or drain spouts) are. Scuppers are usually made of either decorative concrete or metal. Occasionally they are constructed from clay, the same material as clay roofing tiles are made from. Where the majority of these leaks occur is at the area where the scupper material meets the roofing material, forming a gap. This gap is always sealed with some type of membrane, but due to the different expansion and contraction rates between the scupper material and the roofing material, this gap can break open, exposing the inside of the home to water penetration.
In some housing developments where block after block of similar homes have been constructed, using similar floor plans, the same builder, the same general blueprints and the same building materials, one poorly designed scupper detail can result in many homes in that development experiencing the same leak in the same area. I have encountered this situation before.
It was in a burnt adobe town home development here in Tucson called “Villas De Las Canadas,” located in the northwest part of the city. At one time I owned a home there. It is a lovely community of approximately 74 town homes, all built of the same adobe and by the same contractor. The homes were solidly built and constructed of good materials, but one of the unfortunate design flaws were in the scupper details.
Constructed out of metal, these scuppers are attached to the walls in a manner that makes them prone to leak. After a certain amount of time, the portion of the metal scupper that flashed into the wooden roofing plywood would separate due to expansion and contraction. This would occur in one of the most critical portions of the roof, the exact place where the rainwater would gather in just one of several places to rush out of the scuppers. After the rain, these areas would often have water ponding in them, further exacerbating the problem.
Some of these homes, constructed in the 1970’s, had wallpaper that covered the interior of the walls that made up the opposite sides of where these scuppers were attached. Leaks began occurring in these areas, percolating through the roofing membrane and wooden roofing material and seeping into the adobe walls. These leaks eventually made their way into the interior walls, dampening the wallpaper and causing mold to grow, particularly on those homes where these scuppers faced the north side.
Since the north side of a home is usually shaded, these particular areas rarely, if ever, received any sun. In the winters, if these areas received even a moderate amount of rainfall, they remained damp for an extended period of time, creating an ideal environment for mold. The wallpaper on these walls only contributed to the mold problem by trapping the water between the walls and the wallpaper, further preventing the walls from drying out.
The rate that mold grows can be remarkable. On some of these walls, virtually the entire corner of the room were covered in black mold growth. The unmistakeable smell from this mold, hard to describe in its entirety, permeated the room and caused one to experience a slight gag reflex if you got too close to the source.
The source of these leaks were not difficult to establish. Since I have been on many roofs investigating these same type of leaks, I know right where to look: at the spot which I described above.
But what made these leaks more challenging than most was the unusual manner in which these metal scuppers penetrated into the roofing material. There was a slight “dip” created where the end of this style of scupper met the plywood roof decking. It was at the bottom of this dip, where your eye could not actually see this profile, that the entry point for the water began. Unless you were looking for this specific area, you would probably never notice it.
The problem with many of the attempted repairs for these areas is a misunderstanding of the forces that are involved when two different materials materials meet. In this case, you have a piece of metal that abuts up next to wooden piece of plywood. Metal and wood expand and contract at different rates, and applying a repair material like tar over the area where the wood and metal meet only works in the short term.
Petroleum based roofing mastics, or “tar” as they are commonly called, are superior repair methods when the material is first applied. Water and tar don’t mix, as the old saying goes, and this black, sticky substance is excellent in keeping water out of those areas I have been describing.
But the problem with any tar-based repair methods appear later, after the tar has had a chance to cure, usually years after the contractor who applied this repair material. As the tar dries and cures, it becomes hard and brittle, losing its elasticity and its ability to stretch. While the tar was fresh, it was pliable and “moved” with the differing rates of expansion and contraction that occurs with the use of metal against wood, keeping the “crack” covered by tar and preventing water from penetrating into the home.
When the tar dries out and it becomes hardened, it loses its ability to stretch and move with the forces present in expansion and contraction. Now, instead of stretching as the two materials expand and contract against each other, the material snaps or breaks, creating a void which now creates a path for rainwater to penetrate.
Since I’m not a chemist, I don’t understand the chemical transformation that tar undergoes as it ages. How this material can turn from a substance that is wet, sticky and elastic that has excellent waterproofing properties when first applied and then, years later, transforms itself into a brittle and solid mass that is easily shattered, is a mystery to me. All I know is that this transformation happens, and when it does, your house suffers damage.
At first, the cracks that are formed from this transformation from a pliable material to a brittle one are slight…hairline in nature. This means that the passage that is now opened for rainwater to come into your home is constricted; though the moisture now has a path into your home, the water that is allowed in might just be a small amount, causing little or no damage. It’s possible that a quick, light rain will fail to cause any damage at all.
But as the tar undergoes its hardening process, becoming more brittle and unyielding to these expansion and contraction forces, the hairline cracks become wider. This allows more water to penetrate into the home, causing greater amounts of damage. Depending on the amount of rainfall that flows across this area and how cold it is outside, preventing immediate evaporation, water can pond in these areas and wreak havoc on the interior of a home.
When a homeowner discovers a leak in this area of the home and calls someone out to repair it, the repairman will probably come out and, if he has some experience in the matter, will probably perform a simple fix and reapply some black tar mastic over the area. If he indeed discovered the source of the leak and applied a sufficient amount of the mastic, the problem will be solved, but only temporarily.
Depending on the amount, technique and quality of the repair material used, the repair could last for several years. Inevitably, though, this tar will age and undergo the same transformation that all tars do: they dry out, become hard, turn brittle, and lose their ability to expand and contract. Eventually, this repair will also crack at the same spot as before and water will again penetrate into the home.
This regular “call the repairman to come and fix my recurring leak” can become frustrating and expensive to the homeowner. There must be a better way to address these annoying and damaging leaks, and the following paragraphs will explain this process.
Any strategy that seeks to make these repairs more long-lasting must address the problem of the separations that occur between different materials in the ongoing expansion and contraction differentiation. Failure to specifically address this will mean more frustration and damage to the interior of the home due to the eventual failure of the attempted repair method.
There are at least two ways to overcome this problem. First, I will explain a method for repairing these areas while continuing to use the black tar. But part of the main problem on why these areas fail in the first place is because of the aforementioned issues with the tar drying out and becoming brittle.
The best strategy I have found is to do away with the tar and substitute another material in its place. This will be addressed in the second repair method.
Let’s begin with the first method, using a Henry’s type black mastic.
Since we know that these cracks inevitably re-open, we need to apply a “bridging material” that will span this crack and reinforce this area. This material is commonly called a “polyester reinforcing roofing mesh” and usually is yellow in color.
This mesh comes in several widths. I use the mesh that is three to four inches in width. The repair area needs to be relatively clean, free from leaves, small pebbles, etc. Taking a leaf blower is a quick way to clear out the area, but a small brush will do just as well. Have a bucket of clean water and a rag with you and scrub the area clean. Allow to dry.
Before you break open the can of black tar, put on a pair of surgical type gloves. This will not only save your hands from being stained with tar but will also save you much time in cleaning that tar off your hands.
(At this point, let me share with you a secret that is worth its weight in gold: take a bit of petroleum jelly (brand name “Vaseline”) and rub it into your hands, palms, fingers, etc. You don’t need too much. Afterwards, if you get paint or even tar on your hands, it will be simple to clean off because the petroleum jelly will have already created an invisible barrier between your skin and the paint or tar.
Before I learned about this precious little secret, I would spend an inordinate amount of time cleaning paint off my hands. Since I do a lot of elastomeric roof coatings, it is inevitable that you get this material all over your hands and I would waste all kinds of time cleaning this off my hands and from between my fingernails. Now, after applying the petroleum jelly, clean-up is a snap. If you don’t learn anything from this website except this priceless gem, it will be worth all the time you spent in reading this.)
Next, measure the area where you will be applying the mastic and the reinforcing mesh. Ideally, you want to have at least three to four inches of mesh covering the crack on either side, meaning your mesh should be at least six to eight inches in length with the crack right in the middle of this length of mesh. Use a pair of sharp scissors to cut the piece to its proper length.
With a plastic two to four inch throw-away putty knife, apply a generous amount of mastic over the previous repair area that will allow you to completely imbed the mesh tape over and into the mastic. Be careful that you don’t spread the material too thin, but also be careful that you don’t apply too much. An eight of an inch thickness should be fine.
Then, take your mesh tape and lay it on top of the mastic. At this point, you might notice that the mesh tape tends to spring up and curl away from the spot you have just placed it over. If this happens, turn the mesh over so that the curled ends are facing down instead of up. Take your plastic putty knife and gently imbed the tape into the mastic. You don’t have to press down hard on the tape at this point…just enough to make sure that it remains “stuck” in the material.
Next, apply additional mastic over the tape, covering it completely. Proper technique is important here because you don’t want to apply it to thin. You will notice that the mastic will slightly bubble up through the spaces in the mesh tape….this is what you want to happen. At this point, you can apply a bit more pressure on the mesh tape, but be careful that you don’t overdue it because you will then cause the tape to move out of place. This is not a big deal because you can easily move it back into place. What you want to avoid is buckling the tape from applying too much force. If this happens, take your putty knife and your other hand and reposition the mesh.
Cover the mesh tape with another 1/8″ of mastic. Ideally, you should not be able to see the mesh tape coming through the mastic. If you do, apply more mastic until you no longer can see it.
At this point, you have completed the repair. You are now protected from the next downpour.
The problem, though, with using the mastic is the fact that, over time, it will dry out, get hard, become brittle and crack, as I discussed above. But the addition of the mesh tape is going to prevent this crack from reappearing as quickly as it would if you did not use it because you now have some excellent reinforcing properties added to your repair.
Here is where the second repair method comes in, one that is far superior to the tar based repair: repairing these areas using a polyester roofing fabric and elastomeric roofing material.
Instead of using the yellow mesh tape, you want to use a “polyester roofing fabric.” Instead of tar, you want to use elastomeric roofing material, which is a specially formulated coating made for re-coating roofs. Here is a picture of what this looks like:
The brand name of this product is “Tie-Tex.” It is called by other brand names, but this particular brand, Tie-Tex, is the best that I have used. Occasionally, Home Depot will carry the smaller four inch rolls, but I have never seen them carry the large rolls like what you see above. You have to go to a speciality outlet for them. I have used a supplier that for over twenty years has provided me with these large rolls.
The polyester roofing fabric is far superior for repairing cracks than the tar. This is because the fabric, once imbedded in the elastomeric coating, will not undergo the deterioration and degradation that occurs with tar. This means that you will not have all the problems that you have when using the tar.
The one drawback to using the Tie-Tex is that you must use it when the roof is dry and no rain is expected in less than 24 hours. The elastomeric product is water-based, so it can be ruined if it comes in contact with water before it has had a chance to not only dry, but cure.
The tar, on the other hand, can be applied when the roof is damp…even wet. And if it is raining when you are doing the repair or will rain within minutes after the repair is done, no big deal. Obviously you can’t expect the tar repair to last if it is under water or where water is rushing over it, like what you would find if the repair was in a scupper, but tar repairs are very handy if you have to repair a leak in the rain.
The repair procedure for the Tie-Tex using the elastomeric coating is almost exactly the same as what you used with the yellow mesh tape and the tar. The materials react a bit differently, but you will find that the elastomeric is easier to spread than the tar. I use old brushes to apply the elastomeric that I keep in a five-gallon bucket that I tightly close after I use them. These brushes sit in the buckets for years, and as long as you have enough elastomeric in the bucket to cover the bristles, they can last for a long time. I never clean these brushes out because it takes too much time and hassle to do so. After you are done with the project, you place the elastomeric covered brushes back in the bucket, close it tightly, and wait for the next job. No hassles and no clean-up…easy.
You want to insure that you have no wrinkles in the fabric when you spread the coating over it. Nor do you want to stretch the fabric; just place it down on the roof over the crack. You don’t want to “pull” the fabric in any way because this might affect its ability to expand and contract when the temps change.
I have found that two to three top coats over an already dried set of coats is the longest lasting and offers the best long-term protection. Remember, when you are first tackling the job of fixing a leak, you will have at least three coats placed in immediate succession. The first coat is a thick layer of elastomeric coating covering the crack. The second layer is the fabric itself, imbedded in the roof coating. Immediately after imbedding the fabric, the third coat is another thick layer of elastomeric over the fabric…three coats all at once.
These three coats, depending on the weather, humidity and shade, can take some time to thoroughly dry. Even if the top layer appears dry, the bottom two layers will take longer. On a hot, sunny day with little or no humidity, you can easily place all three of the above coats down, allow the top coat to dry, apply the fourth coat, let that dry, and then come and apply the fifth and final coat. We do this all the time with no problems.
Timing, of course, is critical if you are going to put all five coats down in one day. I usually try to be off the roof in summer by no later than eleven and hope fully no later than noon. Even at eleven it is brutally hot in the middle of summer, and being on a roof past twelve in June through August is slightly insane.
I like to start all of my roof repairs and coatings, in the summer, as soon as it gets light outside. Not when the sun is coming up, but when it first starts to get light. This might be as early as 4:45 a.m., but by ten a.m., you will be glad you started so early. Working on roofs past noon in the Tucson/Phoenix/Yuma summer weather is torture, pure and simple.