Leading Home Improvement Expert Reveals His 10 Roofing Pet Peeves

Roofing Pet Peeves - Todd Miller

After years of realizing that certain things in the roofing industry always give me the heebie-jeebies, I have decided to get them off my chest and write about them. Now, these things are sometimes good. But these pet peeves immediately come to mind whenever I run into them on a project, and someone tells me there are problems with that home or roof.

What bugs Todd Miller? Answers and Explanations

Here are my 10 biggest roofing pet peeves with in-depth explanations for property owners and contractors to help avoid problems and protect homes.

  • Skylights and ChimneysThese are not necessarily my top roofing pet peeve, but skylights and chimneys are so inherently evil that I considered giving each their own section in this article. Ultimately, though, they have many similarities, and I will address them together.

    As a roofing manufacturer, I can’t begin to say how many times people have asked me if our warranty would be valid even though they had skylights or chimneys on their roofs. My response is always akin to “You can put all the holes in your roof that you want, but, as the roofing material manufacturer, I sure am not going to warrant that they won’t leak. That is up to you and your roofing installer to figure out.”

    Here’s what I know about skylights and chimneys. Even the best skylights on the market are only warranted for 20 years. And 80% of the time when I have been contacted regarding a chimney flashing leak, the problem was actually with the chimney masonry, not the flashing.

    So, what are the answers?  The best solution is to eliminate chimneys and skylights. And I have eliminated both in my life with properties I owned. But, when that is not something the property owner wants to do, here are my responses.

    If the home is being re-roofed, skylights should be replaced unless they are nearly new and high-quality units.  Yes, I know it’s an extra unanticipated thousand bucks or so. But it’s far better than deconstructing the roof in a few years and replacing the skylights.

    As far as chimneys, have them inspected by a quality mason before replacing the roofing. I don’t care if they look perfect. Have them checked and problems addressed. And then, if the home is being re-roofed, ensure that all flashings will be replaced with new ones.

  • Ridge VentsSometimes, ventilation is not part of the home design, but we need it to control the comfort and health of our homes. It helps keep unwanted and dangerous heat and moisture out of the structure. Ridge vents can play a role in ventilation, but I’m not always a huge fan of them. 

    For most homes, attic ventilation is critical. The exception is a new construction trend involving creating a conditioned space in the attic, often using closed-cell spray foam insulation. In that case, ventilation is sometimes not part of the home design.

    In the 1970s, ridge vents were developed to provide for the exhaust of air from the attic. Before this, exhaust ventilation was done through smaller vents, often called square box vents, slant backs, or turtle vents. Of course, some older homes were so loosely built that active ventilation wasn’t even needed. But, when we brought plumbing indoors and started doing things that created moisture inside our living spaces, we ended up with more moisture migrating to our attics, carried by warm air. If that moisture reaches a cool surface and isn’t vented safely to the outside, the air contracts, and the moisture is forced out of it in the form of condensation. This combination of humidity level and the temperature differential is called “dewpoint.”

    Proper ventilation in an attic consists of intake vents, usually in the soffit overhangs, and exhaust vents, usually at or near the ridge of the roof. Vents will have an NFA (Net Free Air) rating for the amount of air movement that can occur through that vent. You need equal amounts of exhaust and intake vents for ventilation to function. If anything, you want slightly more intake than exhaust venting, creating some pressurization in the attic.

    Building codes call for one square foot of total venting per 150 or 300 square feet of attic floor space, depending on your location.  Northern climates require more venting.

    Another purpose of venting is to prevent hot spots in the attic, which result in snow melting in certain places of the roof and then running down the roof, forming dangerous ice dams and icicles on the unheated overhangs of the structure. 

    Ice dams are controlled through proper ventilation, insulation, and sealing air leaks from the living space to the attic. The goal is to have the attic, both winter and summer, be the same temperature as the outside air, so the conditions outside your home’s ceilings are similar to those outside your home’s walls.

    Why am I not always a huge fan of ridge vents?

    It boils down to the fact that they often perform too well and move too much air.  That may sound a little ridiculous, but if you have a ridge vent with significantly higher NFA than what is provided by your intake vents, the ridge vent will fail. It will draw in weather rather than having the exhausting air push the weather away.

    In most cases, if you enter a floored attic space, you will see a spray pattern beneath each exhaust vent. This means that in some cases, rain or snow is coming in through the vent.  Usually, it’s in minimal amounts, and it quickly dries before it causes a problem. But if you have a ridge vent with very high NFA and you’re not feeding it air from an adequate intake vent supply, you can bring in significant amounts of water.

    Additionally, on low-pitch roofs (I usually say 5:12 or lower), wind-driven rain trying to push its way up the roof can sometimes flood out the ridge vent and end up in the attic.

    Ridge vents can be a powerful air mover to help rid attic spaces of heat and moisture, but if it is not balanced by at least the same amount of intake vent, look out.  You will have problems.  

    Having your contractor analyze your total ventilation package before changing the roofing exhaust vents is always wise. Improper balance of intake and exhaust vents can also drive moisture into your attic insulation, reducing its effectiveness.

  • Log HomesEveryone loves the beauty and charm of a log home in the woods. At the risk of sounding curmudgeonly, everyone but me. Most of us picture a log home with a green, red, or blue metal roof. I shudder when I think about how many calls I get about picture-perfect metal-roofed log homes.

    There are a couple of frequent issues I see with log homes.  One involves condensation.  The fault may lie with the geometric design of the roof and home, making it difficult to ventilate the space above the living area. Or it may involve the logs themselves, especially as they age. But log homes frequently have moisture control issues and resulting condensation.

    About half the time, when a homeowner contacts me regarding condensation and moisture problems, it is a log home. And it doesn’t take a rocket scientist to conclude that not half of all houses are log homes.

    Log homes are often built with virtually no attic ventilation. Sometimes they have vaulted cathedral ceilings, and sometimes, they have knee walls in the attic that stop airflow.  The result is a collection of unwanted high moisture levels near the roof’s peak and condensation issues, including mold and mildew.

    The other common concern with log homes is that often, the house design involves lots of dormers and other roof protrusions against which the roofing must be flashed. There are enough problems flashing against a flat wall, let alone a wall made of curved logs! At some point, in virtually all cases, those roof-to-wall intersections on log homes will be a problem. Oh, and flared gables – don’t get me started on those!

    Over time, the designers of log homes have worked to address these ventilation and flashing issues, so things are improving. But, if you’re buying an existing log home, these are critical areas to look into. And, if you’re having a new log home built, don’t be shy to ask your builder how they will handle ventilation and any roof-to-wall flashings. 

  • Gutter CoversNo one likes the yucky, slimy mess of cleaning wet leaves out of their gutters. And, if you’re like me, you tend to put it off until the last minute, so everything is freezing cold. Gutter covers, designed to keep leaves out of a home’s gutters, are sometimes considered the greatest thing since sliced bread. But they bug me.

    Covering the gutters with some sort of perforated protection makes a lot of sense, doesn’t it?  But, once you begin researching the options for gutter covers, you will find many products available today. All kinds of different styles and approaches to solving the same fundamental problem. Do you want to know why there are so many options? It’s because no one has yet developed the perfect or ultimate solution. All of the systems have drawbacks. If the perfect solution existed, everyone would produce it.

    Typically the “hood” style systems cause water to overshoot the gutters. I guess that’s one solution to the problem!  Over time, as the painted surface on the hood starts to oxidize and develop some surface tension, things may improve. But my father had his hood-style gutter cover removed about three years after it was installed, convinced it would never work well.

    And, if the helmet cover is not correctly positioned or becomes dislodged due to ice or snow or something else, it can start to dump water back against the house, rotting out the eave and fascia boards.

    Other gutter protection systems lay flat in or on the gutters but tend to clog with dirt and debris over time – especially the ones that use fine “surgical” mesh. I’ve even seen some of these systems start to grow their trees and weeds over time! That said, I will give a shout-out to the system I like the best – the least of all evils if you will – and that is the Leaf Relief system by Plygem. (Your local lumberyard also probably sells a vinyl mesh in 4’ pieces at a very low cost, and it can work very well as a DIY product.)

    You will also find that many of these systems are incredibly expensive – highway robbery, you may say. You can afford to put wire mesh covers over your downspouts and then hire a professional twice a year for many years rather than invest in a gutter cover that will bring heartache.

    The damage caused by a gutter cover can be very high over time if it contributes to eave or fascia rot. Especially with metal roofing, if your fascia or eave decking rots due to damage caused by ice, snow, or rain being misdirected by a gutter cover, the cost of making repairs later can be astronomical.

  • Low Pitch RoofsA significant pet peeve of mine is encountering a beautiful home with a great roof with a good pitch to it, and someone has either designed in or cobbled on a porch roof with a 1:12 or 2:12 pitch. Over time, low-pitch roofs tend to have problems. 

    There are many approaches to protecting low-pitch roofs. Some of those approaches are not attractive aesthetically—and very few approaches tie in cosmetically with the rest of the roof.

    Often these roofs are at the bottom of a steeper roof and must carry the water from the more vertical roof as well.

    Another problem with low-pitch roofs is that because their coverings don’t last as long as those on steeper roofs, they must be replaced more often. If they have a direct connection to the steeper roof, over time, that connection gets “complicated” as it starts to flatten out and has many sealants put on it. And it can even eventually start to pond water or direct water “uphill” into the higher roof system.

    If you’re building a new home with a low-pitch roof, see if there’s a way to increase the pitch. If not, see if there is a way to put a vertical drop of 6” or more from the higher roof to the lower roof. This drop will facilitate future roof replacements.

    If you are re-roofing a home with a low-pitch roof, ask your contractor if the pitch of the new roof can be increased. Or, if not, be sure you understand what that connection between the two roofs will consist of and make sure there’s a good plan for future replacements of the low-pitch roof. Also, with some metal roofs, color-matched roofing will be available for roofs below 3:12 pitch.

  • Through-Fastened Metal RoofsAlso known as exposed fastener metal roofing, through-fastened products are sheets of corrugated metal attached to the roof using exposed screws. Often used on agricultural buildings, they are increasingly used on homes. I call these “entry-level” metal roofs. Here’s why:

    In thinking about these roofs, it’s essential to consider the goals and wishes of the homeowner buying a metal roof. Are they seeking long life, freedom from maintenance, lower energy costs, and other things? If so, the through-fastened roof product may not meet all of their goals.

    3 Weak Spots of Through-Fastened Metal Roofs 

    To prevent leaks, the screws of the roof typically have only a cap head and a neoprene washer.

    1. Because these systems have no allowance for thermal expansion and contraction of the metal, the screws (which have a limited life due to their washers) tend to loosen over time. The holes in the metal panels surrounding the screws tend to wallow out over time. 
    2. The success of the screws depends heavily on the screws being driven in absolutely square to the metal panels themselves – something that is not always easy to do on a sloped surface.
    3. These panels often have underperforming coatings on them. Keep reading to #7 for an explanation.

    While through-fastened metal roofs fill a niche for affordable metal roofing, I caution folks about “over-selling” their benefits. When investing in a metal roof, many people do so with specific goals regarding the life expectancy and maintenance costs of that roof. If they purchase an “entry-level” through-fastened metal roof, they need to be well-informed that the life expectancy will not be as long as a more “investment-grade” metal roof and will likely have some maintenance costs. They also need to understand the importance of the screws all being driven in squarely and properly seated.

    In this case, I guess that my pet peeve isn’t so much the roofing product itself as it is that homeowners are often being sold this product thinking it has the same benefits as the better metal roofs they have heard about.

  • Under-Performing Metal Roof CoatingsThis pet peeve is similar to through-fastened metal roofs. The fact is, metal roofs come with various available coatings, each with its own attributes and price point. I often find that folks selling the lower-priced options are not fully transparent in explaining the limitations of their products.

    This pet peeve is similar to through-fastened metal roofs. The fact is, metal roofs come with various available coatings, each with its own attributes and price point. I often find that folks selling the lower-priced options are not fully transparent in explaining the limitations of their products.

    Two common chemistries of paint finishes are used on metal roofs, and a third option is starting to appear on the scene. The two basic types are Polyester and PVDF (polyvinylidene difluoride). The emerging type is FEVE (fluoroethylene vinyl ether). Additionally, some Galvalume products have a clear acrylic coating, and some metals, such as copper and zinc, are sold as mill finish metals. Finally, a stone or aggregate coating is another type of coating found on metal shingles.

    Polyester finishes and the clear acrylic coating on Galvalume are what I call “entry-level” finishes. These are the lowest-cost coatings; in particular, with the polyester finish, you will find several variants.  The clear acrylic coating weathers away after a few years, exposing the bare Galvalume. 

    The various polyester coatings are available in a wide variety of colors and even textures. Their drawback is that they are prone to fade and chalk, especially after about 7 – 10 years of weathering. Of course, this will be most pronounced in areas subject to high UV or other things such as salt spray.

    Anyone with experience in the metal roofing industry will tell you that PVDF finishes are the best performers. They have superior pigmentation for color retention, and the PVDF resin is very long-term, helping to avoid chalking. FEVE finishes will have similar performance but are newer to the scene, brought here by supply chain issues that have impacted PVDF as PVDF is also used in lithium-ion EV batteries. Of course, these products are the highest-cost finishes, and there has been plenty of upward pressure on those prices in recent years.

    Polyester finishes are common on through-fastened products, while standing seam products are typically available with both polyester and PVDF / FEVE options.  Metal shingles usually have PVDF coatings, but stone (aggregate) coatings are also used. Stone coatings provide a nice look as they look similar to asphalt shingles.  That creates a nice “bridge” for consumers from asphalt shingles to metal. However, stone coatings can be much more prone to dirt retention, streaking, and staining than other coatings in damp or tropical environments.

    Again, my pet peeve is not the availability of lower-performing coatings; it has more to do with coatings being “over-sold” so that property owners may not get the durability they expect.

  • Structural Insulated Panel (SIP) Roof DecksI remember seeing a house being built with SIPs (Structural Insulated Panels) for the first time a little over 30 years ago.  I was fascinated and convinced that this practice would become quite commonplace in the future. I’ve since dealt with the challenges of this construction method. 

    About ten years after first seeing that house, I was called to a project where the ridge caps were flying off the house. The homeowner assumed there was a roof leak that was causing the failure. However, when we removed the ridge caps, we found the underlayment beneath them was pristine. The problem was that the house was built with structural insulated panels, and this was before everyone realized the damage that moisture would cause if it crept into the joints between the panels.  This house had high interior moisture levels because the occupant was an artist, and much of his work involved water. But moisture had migrated (as it does) to the peak of the SIP panels, where it condensed and rotted out the decking.

    Over the years, many folks have sent me photos of failing asphalt shingle roofs, and based upon what is going on, I often ask if the home is built of SIP panels. Usually, when I ask this, they respond, “Yes, is that a problem?” Actually, I had one homeowner once who took me to task, insisting that his SIP panels were not part of the problem. Once we did a little deconstruction and some core samples and fastener pull-out tests, he understood clearly that the insulated panels were the problem.

    Now, there is nothing inherently bad about these panels.  And, over the years, their quality has improved.  If the joints are properly sealed, they will be tight against water vapor. You can also do things like using oil-based paint on the interior to help discourage moisture from the living space from migrating into the panels. But, if moisture does get into these panels, it will be a problem.

    One perceived benefit of these panels is that they are sometimes used for vaulted ceilings, which means no ventilation. Even over an attic, ventilation is sometimes not used in SIP construction. However, if moisture gets into the panels, the likelihood of it reaching a cold spot and condensing is very high.  And that creates problems such as asphalt shingle roofs where large patches of shingles have blown off due to rotted decking.

    Of course, there are always answers to these problems, and a common one is to build a vented “cold roof” on top of the SIP panels to keep the panels from getting as cold and vent out any moisture that does migrate through them. Metal roofing can be an excellent choice on top of a cold roof due to its low weight.

  • Metal Roofs Installed On BattensOver the years, I have heard of many “old-timer” roofing contractors swearing that metal roofs must be installed on battens. This is not true, at least not in most cases. Installing a metal roof on battens, though, will make the roof harder to walk and repair and also potentially make the roof more prone to wind uplift.

    There are many reasons given by batten advocates, most of which have to do with condensation or heat transfer. Indeed, putting the roof on battens does create a helpful thermal break, but there are other ways to do that, such as metal shingles with integral thermal breaks or putting standing seam or through-fastened roof panels on top of a thin entangled mesh. So, I appreciate the energy efficiency of a thermal break. I’d just rather see it be achieved in ways other than battens.

    As far as condensation, nothing is inherent about metal that makes it create condensation. Condensation occurs when dewpoint is reached as warm moist air drives out of the structure. If the home has used proper ventilation, insulation, and a vapor barrier behind the ceilings, there will not be condensation issues. While battens could be helpful in some extreme situations, they generally are not required to avoid condensation in a metal roof system.

  • Metal Roofs Without Solid DecksWhile I have not ranked my list of pet peeves in terms of what peeves me the most, I am wrapping up with the one that probably drives me the most nuts.  Let me get to the bottom line: Metal roofs should never be installed on residences without solid decking as part of the roof system.

    Yes, metal roofs are installed on commercial, industrial, agricultural, and even religious buildings all the time without decking. However, those buildings inherently have lower moisture levels and more air exchanges. They also are bigger buildings with a higher air volume for moisture distribution.

    On a residence, though, installing a metal roof without underlayment and solid decking (even if battens are installed on top of the decking) is a recipe for condensation disaster. And no one wants that.

    Over the years, I have even had homeowners call me who had this situation, and they told me that their contractor removed their solid roof deck before installing the metal roof because “it was the right thing to do.” I guess it is the right thing to do if you want to leave your clients with an absolute nightmare.

    While every residential metal roof installation must be carefully evaluated and such things as ventilation and condensation risk must be taken into account, having a solid deck as part of the roof assembly along with appropriate roofing underlayment is critical.

Thinking ahead can prevent the development of your roofing pet peeves! Addressing these pet peeves of mine for the good of homeowners is relatively simple. I hope you’ll lean on my years of experience to do these things or ask for help in solving future problems of poor roof design, installation, or products.

Contact me anytime to ask a question or give and receive feedback. Thanks for reading.