JB SORIA Roof & Building Repair
|Posted on 15 March, 2015 at 20:40|
With this article I'll attempt to provide an unbiased perspective of claims made by the manufacturers of the various coating products found on the market today. I'll also dispel some of the false claims, myths or what I refer to as BenefitS without the "enefit", of others. While many will view this as but one man's opinion, I haven't arrived at these conclusions lightly. Not only are they based on my over 40 years experience working in the industry but also from opinions of manufacturers' and independent researchers after many years of scientific studies and field testing.
Take the time to read the analysis of several roof coatings below and hopefully you'll be in a much better place to make a decision on your building.
STEEP SLOPED TILE & SHINGLE ROOF COATINGS:
Most coating options for both of these types of roofs have been widely debunked by experts. Because of this, I won't devote too much time here on either of them.
Tile Roof Coatings.
This is a trend that has surfaced only recently, perpetrated primarily by unscrupulous contractors. The National Federation of Roofing Contractors disputes these claims in the following article: http://www.roofapedia.com/Roof-Info-Centre/3/Roof-Coatings.aspx
"There are companies who specialize in cleaning and re-coating or painting existing tiled roofs. The claims made by these companies include statements that the application of a coating or surface paint will increase the thermal efficiency of a roof and will prolong its life. They also claim that mosses and lichens‘ eat into the strength of the tiles and roof tiles are not waterproof. Unfortunately, none of these claims are true, but before you read about why, we should also talk about price. It is not uncommon for home owners to be quoted prices for roof coatings that are equivalent to a completely new roof. If you are considering a tile roof coating, it pays to ask for a quote for a new roof from a reputable roofing contractor, as a comparison..."
The article goes on to explain their conclusions in greater detail. To me, the idea that tile roofs will lose their strength or efficiency in this manner is quite ludicrous.
Asphalt Shingle Roofs:
Most of my business these days consists of repairing existing roofs. When called upon to repair a shingled roof that's been coated, I usually won't give it a second look. The 2 main reasons people tend to coat them are to add insulation value and preserve the granules from premature wear. From all I've read, the added insulation value may not be any higher than 1/10th of 1%. Certainly not enough to move your electric bill's needle. As for preserving the shingles, quite the opposite is generally true. The alternating space in between each shingle and tab- known as "Chimes"- is critical for proper runoff. When coating shingles, its virtually impossible to cover each chime as well as the horizontal seams. In doing so, I've often seen where ponding is created backing rainwater onto the nails beneath. Rusty nails will eventually loosen, then eat into the overlapping shingle. Worse yet, this coating will inhibit the asphalt's ability to contract and expand properly with seasonal temperatures resulting in premature wear, cracks and breakage to the shingles. Its also almost impossible to locate leaks and repair them on coated shingles. For that reason, I won't even attempt it.
LOW SLOPED FLAT ROOF COATING OPTIONS:
While Roof Coatings may not be the best solution for every roof, most building owners of low-sloped roofs- especially here in the South-West- know they can be a lifesaver in keeping the inevitable, costly complete re-roof job at bay for possibly decades. When it is decided to be your best option, how does one decide which roof coating is best for your roof?
Aluminum and Asphalt Emulsion Roof Coatings
These are the coatings I first became familiar with as a youngster in the mid 1970's while working in my father's construction company. Although he wasn't a roofer by trade, we always installed our own rolled roof products on any patio, carport or other flat roof additions we built. In those days, we'd most often use inexpensive, granulated rolled roofing material. The aluminum coating actually did add significant life to those. In coating older worn flat roofs, we'd often use a fibered asphalt emulsion to add pliability prior to the aluminum coating. This is asphalt which is actually emulsified with water crystals to increase adhesion. Its a rather inexpensive product but I've learned since that many other materials don't easily adhere to it unless its well cured. Even then, that adhesion eventually breaks down and no surface coating can restore it.
The advantages touted by proponents of aluminum roof coating supporters is their relatively low cost and reflectivity. One of the most significant cost considerations of aluminum coatings are the application requirements. The temperature must be just right for the material to be properly applied. There are also often requirements of primer usage on the roof to obtain proper adhesion..
Reflectivity is an advantage of all roof coatings, so it is not really a selling point of aluminum over any other roof coatings. The reflectivity is an advantage over other systems that don’t provide the reflectivity, but any roof coating can be reflective.
Aluminum roof coatings may be aesthetically pleasing when first installed, but that look often fades and they can become somewhat of an eyesore if the building is in sight of others. Also, while its reflective abilities help preserve asphalt materials quite well, aluminum coatings tend to retain much more heat than white coatings, adding virtually no insulation value.
Acrylic Roof Coatings
This is the less costly version of a seemingly "elastomeric" white roof coating. While it may look the synthetic blended elastomerics described below, it is far inferior in most aspects.
It is widely believed that the most significant advantage of acrylic roof coatings is the price. While acrylic roof coatings are typically viewed as the most cost effective roof coatings, this is a common misconception that has cost many building owners a lot of money. Sometimes even unknowingly, as some installers with sell homeowners on the idea that their lower costs as being strictly due to lower labor charges.
Acrylics are the cheapest white coat material in the flat roofing market. But if you're a do-it-yourselfer, please keep in mind it takes more acrylic coating to cover the same area as most other coatings, and acrylic often requires a primer upon installation. Acrylic has a much shorter useful life than most other coatings, and must be replaced, which means more cost. Acrylic coatings also do not provide the same protection from the elements as other coatings, so repair and energy costs are often higher.
Acrylic coatings are extremely common in the flat roof market today, mostly due to the not accounting for their true material life costs. They are also often chosen thanks to their reflectivity, which keeps the interior of the building cooler, but this characteristic is available in all roof coatings. They also have a much lower tensile strength, which means they don't stretch out as the building flexes thus becoming more susceptible to wear and tear. This often decreases the value provided by the coatings as they do not last as long as expected.
Most experts agree, acrylic coatings are not right for many situations. They appear to be the less expensive option, but often end up costing more than all other roof coating options would have. On top of their cost structure, they do not provide the same value other coatings are capable of providing in terms of protection and lifespan.
Elastomeric Roof Coatings With Synthetic or Polymer Additives:
Elastic/Polymer based roof coatings were originally developed for metal roof applications, but soon became most popular on many flat roofing systems. These coatings are typically water-based, and one of their greatest strengths and main purposes is to reflect UV rays and resist picking up dirt.
Each manufacturer formulates their version of this type coating a little differently and some have even patented their formulations. Those formulated and tested in like climates as yours will usually be best suited for your roof. After visiting several of these factories and test facilities, I've come away very impressed with a few brands I prefer.
While other coatings can often lose their reflectivity over time, the formula in these products allow them to resist UV rays for longer without fading or losing effectiveness.
The surfaces of roofs with this type coating, when analyzed microscopically, are extremely smooth. Most roof coatings, and roof surfaces in general, have small imperfections on the surface that can hold onto dirt and other debris, making the roof surface very dirty very quickly. However, Elastomeric roof coatings are specially formulated to have a very smooth surface once dry, which allows dirt and debris to quickly run off the surface of the roof. For this reason, Elastic/Polymer coatings are often chosen on buildings where aesthetics and reflectivity are of utmost importance.
The most important considerations with these particular coatings are proper adhesion and manufacturer's recommended spread rate.
In order to achieve maximum adhesion, the sub-surface beneath must be thoroughly cleaned and any loose prior coating or patch materials must be scraped and repaired, otherwise you're attempting to adhere it to those sub-standard surfaces. In most cases, I will pressure wash the roof first to remove built up grime and any loose previous coating. However, I'd only recommend this method if you're familiar with how much pressure to reasonably apply to prevent further damage. Its also crucial to use manufacturer's guidelines for gallon per sf spread rates when applying these coatings in order to meet their full warranty standards.
One of the biggest benefits white coatings have over all others- including the more costly options which follow- is the higher insulation value, which can add up to an impressive 5-10 points of R-value to your existing insulation!
EPDM or Silicone Based Roof Coating:
These rather costly coatings have many characteristics that make them the best solution in many situations. They have a much higher solids content than other roof coatings, which means they can be applied thick in a single coat with losing the integrity of the system. These are the ones you see on stadiums, airports and other high use and public facilities.
EPDM roof coatings can have low labor costs as compared to other roof coatings. They rarely require a primer to achieve proper adhesion, can often be applied in a single coat, and need less fabric reinforcement than most other coatings.
While the initial cost of these materials will be higher than other roof coatings, the true cost of the roofing system often ends up lower than other systems. Thanks to their long lives- lasting 2 or 3 times as long as the better elastomerics-, life-cycle costs can actually be deemed as fairly low.
Other benefits of EPDM and silicone roof coatings include UV resistance and stability, somewhat easy installation for contractors, and the lowest VOC content on the market, which is good for the environment.
Do-it-yourself'ers need to keep in mind, these products require a catalyst to be mixed in at the point of application, which eliminates preserving any left-over product.
Most manufacturers offer "Limited warranties" on their products, some for an impressive 10 years or more. However, as with most warranties, the devil is in the details. Reading further in those warranties, you'll find enough exclusions to cancel out almost any claim. Here are a few out-takes of actual exclusions I've pulled from some of the warranties I've encountered:
"Faulty or improper application of the White Coatings or White Coatings
not installed or applied exactly in accordance with (mfg's) written instructions or
leaks or damages resulting from any one or more of such causes." Its virtually impossible to prove this years after the fact.
"Leaks or damage to the White Coatings from any cause other than
inherent manufacturing defect in the White Coatings." According to this one, it seems they won't even warranty their own material unless it can be proven to be defective.
"Damage caused by foot traffic during installation, maintenance or use of equipment
installed on the roof, including, but not limited to, air conditioners, heating units, antennas, power lines or solar systems." I guess regular AC or other equipment maintenance requires the use of a hovercraft, as walking on the roof can be deemed as damaging in this detail.
"Damage caused by factors that are beyond the control of (Manufacturer)." A last ditch stand-by if all other exclusions fail.
I'm not saying they're being purposely deceptive. I'm sure they have to protect themselves from the many unqualified installers in the industry.
For these reasons, its most important that you use a reputable installer who offers their own warranty. Most of my full coating jobs include a 5yr material & workmanship warranty with very few exclusions. Most qualified professionals will do the same.
Without knowing the specific details of your buildings, it is very difficult to make recommendations on the exact roof coating you should choose. However, hopefully this post provided enough information that you can use to help you determine which one is best for your particular roof. If you have any questions or would like to learn more, please use the "contact us" link on my home page. I'll attempt to respond to all requests within a reasonable amount of time and no sales tactics.
Categories: Roof Repair Tips