Archive for the ‘Technical’ Category

Painting and Protecting Metal Roofing: Anodized vs. Paint vs. Powder Coating

Wednesday, February 15th, 2017

Any roof, no matter the product type or color, is only a good one if it is durable and does not leak. Versatile and malleable, aluminum roofing is a wise, cost-effective option for your home. There are three good options for protecting metal roofing. Paint protects surfaces and adds color, but metal roofing is different from other materials. To protect the material from the elements and to visually enhance the result, metal roofing can be anodized, painted with liquid, or powder-coated.

Anodizing

Anodized aluminum roofing has a protective surface coating of aluminum oxide that is applied via an electrochemical process. Because it is durable and weather-resistant, anodizing is a common, effective, and long-lasting protection for applications like standing seam metal roofing. The thicker the anodic coating, the longer it lasts.

Anodized coatings may be dyed almost any color. They will also take on bronze overtones naturally due to a diffraction phenomenon the coating itself produces over time. Anodized metal does not lose its coating, which grows integrally from the base aluminum and thus neither peels nor flakes, permanently sealing the aluminum roofing underneath against the elements.

Painting

Painting or powder coating also protects and colors metal roofing. However, these paints and powders should be factory-applied rather than completed DIY. Of the many resin options, PVDF performs exceptionally well on metal roofing in harsh weather environments. PVDF-coated aluminum roofing generally outperforms anodized metal. It is not only resistant to extreme weather, but also to chemicals, UV light, flaking, and chalking. Also contributing to PVDF’s popularity is the nearly limitless range of color possibilities.

kynar-layer-system-img

Kynar500® and Hylar5000® are the two leading products, virtually identical in all but name. Both yield the same superior-quality finishes; what is more, these products are usually warrantied for 30 years up to five Delta E units, which is the measure of the smallest perceptible color shift.

Powder Coating

Powder coating, on the other hand, is essentially “paint without the solvent.” Powder paints encapsulate pigment inside powdered resins. When composed of the same resins, the powder and liquid versions perform similarly by comparison. Because they are applied electrostatically after the product has been made, these “post-forming” double coatings not only beautify, but they also help correct any potential flaws or fissures in the base protective coating applied by the manufacturer.

A significant environmental benefit accrues due to less air pollution from the oven-curing manufacture process for powder coatings as compared to liquids. Kynar powder coatings are leaders in this innovative product category. When reflective metallic pigments are integrated into Kynar powder coatings, the stunning results are also money-saving. Reflective powder coatings deflect significant UV radiation away from the attic, keeping the house cooler and in turn reducing energy costs. When combined, Kynar paints and powder finishes provide superior color quality and long-lasting protection.

Metal Roofs – Aluminum vs Galvanized/Galvalume

Thursday, January 26th, 2017

All Metal Roofs Are Not Created Equal

The benefits of metal roofing in New England cannot be disputed. Although not all metal roofs are created equal, nor are they installed in the same manner. We are going to cover a vital item that is highly significant when it comes to residential applications. That is the base metal used for the roof.

Base metal, when used in the context of construction, is the primary component used in construction material, from the sheets of roofing exposed to the elements, right down to the fasteners contained beneath the roof. When used as part of a roof assembly, the base metals can be steel, aluminum, copper, or zinc, or a combination of base metals. All base metals have distinct properties which contribute to advantages and disadvantages in longevity and appearance when applied in various climate zones.

We will focus on two widely used base metals used in roofing: steel and aluminum. Steel is a hard, strong, gray or bluish-gray alloy of iron with carbon and usually other elements, used extensively as a structural and fabricating material. Aluminum is a silvery-white, soft, nonmagnetic, ductile metal. Both metals can be used for roofing. Steel can be used for structural roofing and architectural roofing. Aluminum is primarily used for architectural roofing. Architectural roofing does not require structural integrity in the construction assembly.

Galvanized and Galvalume Steel Roofing

It is important to note that base metals can be combined, coated, or layered with additional metals in a variety of bonding processes. Two popular roofing materials that use this process of binding two or more dissimilar metals are referred to as galvanized and galvalume, each of which use steel as the base metal. Iron or steel can be coated with zinc; this is known as a galvanized metal. The zinc acts as a protective layer to iron or steel to prevent rust. Galvalume is aluminum and zinc coated steel. The combination of aluminum and zinc is used once again as a protective layer to the steel. Steel exposed by itself without other protective metal coatings such as aluminum or zinc turns a reddish- or yellowish-brown flaky coating of iron oxide that is formed on iron or steel by oxidation, especially in the presence of moisture. It is what we refer to as “rust.”

Rust has been called “the great destroyer” and “the evil.” The Pentagon refers to it as “the pervasive menace.” It destroys cars, fells bridges, sinks ships, sparks house fires, and nearly brought down the Statue of Liberty. Rust costs America more than $400 billion per year—more than all other natural disasters combined. (reference: RUST: the longest war)

What Happens When the Protective Coating Wears Off?

Everyone has come across rust at some time in their life. We have all seen it before. Rust is unsightly. Shiny spokes on a bicycle wheel, or a dented corner panel on a car, all show the common enemy of rust becoming evident eventually. The question is would you want to see rust on your home’s roof in the future? Which base metal assures no rust whatsoever over the course of the roofs life? The only one of the three base metals we have looked at that is rust-proof is aluminum.

Metal working requires tools which bend, cut, and shape metal roofing components. Roof valleys and ridge caps are bent, roof edges are cut, and panels are formed and shaped depending on the particular style desired. All of this metal work by mechanics contributes to stresses on the metals and exposure of edges where a base metal may lose the protective coating, be it another metal or paint finish which is meant to keep it from rusting. This is particularly true for galvanized and galvalume roofs where the base metal steel is now exposed to the elements. Warranties for galvalume and galvanized roofing will call out a certain acceptable amount of rust from any edge that is cut within a specified period of time. Do you want to look up at a newly installed metal roof and wonder when the rust will show up, the paint finish will start peeling, and rust will begin running down your siding? I suspect not. So if that is true, you will want to choose to have an architectural aluminum roof installed, as aluminum does not rust. Aluminum, as you remember, is used to coat steel in the galvanized and galvalume products. You also do not want the fasteners holding your roof on, which may also be galvanized undergoing deterioration.

galvanic reaction on metal roof

The photo above shows galvanic reaction occurring, through the paint finish no less, of a steel based roof underneath the flashing of a drip edge above. This would not happen in a Kynar resin paint finished aluminum roof.

drip edge and rib bend in the galvalume standing seam roof

The photo above shows the drip edge and rib bend in the galvalume standing seam roof of the same home. If you examine the photograph closely, you will see the paint finish has chipped away underneath the drip edge where the steel base metal has begun to deteriorate (rust).

galvalume metal roof failure on commercial building

It is common for commercial buildings to use galvalume roofing as an initial cost saving measure. In the photo above we are beginning to see the failure of the paint finish along the seam of the bent metal. The failure is either in the paint resin, or the manufacturing process when the finish was adhered to the metal coil. Galvalume has a coating of aluminum over the steel and will likely take more time for rust to occur at the exposed locations of the panel. However, wear occurring along the roof’s drip edge where all the water and snow run off will eventually wear away the aluminum coating once the paint finish fails, and rust will ensue.

Only Aluminum Offers Long-Lasting Protection While Remaining Aesthetic

Paint finish warranties are key to understanding the expected longevity of a galvanized or galvalume metal roof. Aluminum roofing comes with paint finishes, as well, and have their own warranties. The big difference is that aluminum will oxidize/chalk if exposed to the elements, but the aluminum will not look unsightly and continue on with a rapid oxidation process (deterioration/rust), as steel will.

Be sure to visit Classic Metal Roofs website to see non-rusting roofs made with aluminum for your next architectural “metal” roof.

Written by Bryan Rusch, Partner at Classic Metal Roofs LLC. Additional articles related to metal roofing can be found on Bryan’s LinkedIn profile here: https://www.linkedin.com/in/bryanrusch

How to Properly Flash Roof Pitch Transitions with Standing Seam Metal Roofs … “The Right Stuff”

Thursday, December 29th, 2016

Pitch Transitions Are a Common Roof Detail

A roof pitch transition is a line in the roof plane that changes pitch. The roof plane goes from one pitch to a lower pitch. This is a fairly common roof detail. We see this quite frequently in Log Home roofs with porches, for example. See the illustration below.

roof going from higher to lower pitch

As you can see from illustration the roof changes pitch at the porch from a 9/12 to a 3/12 pitch. By the way, pitch is measured by picking any point on the roof, place a level on it, measure 12” out from that point (this is called the run) and then down to the roof surface from the bottom of the level (this is called the rise) to see how many inches the roof pitches over 12”.

roof pitch measurement illustrated

Pitch Transition Points Can Be a Source of Problems

The transition point can be a source of problems if not done correctly. The transition has to be prepared properly with the right underlayments including high temperature ice and water shield when metal is being installed. Then a high quality synthetic underlayment should be installed as well.

Many times we will see a transition done by someone who just bends the metal panel to conform to the transition. See below.

standing seam roof pitch transition done by bending metal panels

A careful look will show this change in pitch was done haphazardly and shows a lack of metal roof installation knowledge. You can see that where the metal is bent and changing pitch. The metal is badly crimped and beginning to fail. The metal is cracking due to the movement of the metal and a poor installation. There is considerable oil canning, as well, for such short panels and there is no snow retention over the front door. This roof was installed only 8 years ago. How do we know this, you might ask? We gave this homeowner an estimate. He said our price was too high. We don’t think the owner was expecting this outcome. He got what he paid for…. a cheap metal roof.

Larger Roofs Can Lead to Larger Problems

The next picture shows that those problems can be multiplied when the roof is larger. Not only was the transition flashing not done, but the outcome was far worse due to the size of the roof. You can see the oil canning due to the stress on the panels and the inability of the panels to move freely because they were not terminated at the transition and properly flashed. Just plain UGLY! Definitely not “the right stuff.” We do not know which company was responsible for this roof.

large standing seam roof pitch transition done by bending metal panels

Make Sure Your Roof Installer Has the “Right Stuff”

The next picture shown a log home with a classic transition change for the porch roof. You can see the transition flashing which separates the two roof planes at the pitch change. This flashing detail is important to maintain the integrity of the roof and it also helps to prevent oil canning as you can see from the picture. This roof was correctly done about 6 years ago by our own crew.

standing seam roof pitch transition correctly done by Classic Metal Roofs

This roof was done with “the right stuff.” It is not just a metal roof. It is a Classic Metal Roof: “The best roof under the sun.”

Roof Insulation & Ventilation in Log and Timber Frame Homes

Friday, December 16th, 2016

New England is a mecca for Log and Timber framed homes. It is also known for some of the craziest weather extremes and weather swings in the country. Roof insulation, as well as roof ventilation, is a topic that comes up in our daily conversations with our clients.

What is the correct way to insulate and ventilate a log or timber frame construction roof? By this question, we mean what amount of insulation should you have and should the roof be vented?

SIP Panel No Air Chamber

The “SIP” panel shown here has no air chamber and would be a Hot Roof system.

Building code requirements in MA have set the R value of roof or ceiling to unconditioned attic space at R 38. That is a great place to start. We have seen some projects go to R 45. An investment in insulation is well spent due to the rising energy costs. We all know that energy costs will not come down. If you are building a new home, there are several things to consider, including not only how much, but what type of insulation you are going to use. It is not the intent of this post to convince you of one type of insulation or another, nor are we suggesting a vented, cold roof system or a non- vented hot roof system.

Our intent is to make the reader aware of the options and the pros and cons of each.

One option that is widely available in new construction regarding insulation is the SIP panel roof. A “SIP” panel is a structural panel available in a multitude of dimensional sizes and thicknesses. They consist of some type of foam core insulation sandwiched between two structural boards. These types of insulation roof systems can cut construction cost, as they go in very quickly. They are also available with built in air space for ventilation or no ventilation in a hot roof configuration.

SIP With Vent Chamber

The picture above shows a “SIP” panel with a vent chamber. This would make the system a cold roof.

Then there is the option of using some sort of spray foam. This has become widely used today in new construction and is available in both closed and open celled foam.

First let’s consider closed cell foam insulation.

With closed cell foam insulation, the cells are closed and densely packed together and they are smaller in size. They are mixed with a gas which expands the foam. Because the cells are closed, this prevents air and water vapor from infiltrating, a well-engineered advantage that its open cell counterpart does not offer. It works very well as a roofing insulator and is also available in several densities.

The benefits:

Closed cell foam is very strong and ridged with significantly higher thermal resistance than most of the other options. It also prevents leakage of air and water vapor migration.

The disadvantages:

Because it’s more dense, it requires more material, which makes it more costly than the open cell option.

Closed cell foam has a higher R-value. The higher the R-value means more effective insulation; the rate per R value is higher than that of open cell foam.

What about open cell foam insulation?

Open cell foam is composed of tiny cells which are not enclosed. This type of foam is not as expensive. It works in blocking out air but is not an effective barrier against water vapor. Since the cells aren’t closed, air fills up the open space inside the material sometimes causing the foam to become weaker and easier to penetrate in comparison to the closed cell option.

The benefit:

Lower cost and an effective way to get a thorough insulation barrier in the roof.

Whether the choice is closed or open, spray foam insulation is a proven method to reduce energy expenses. Buildings in the U.S. with spray foam insulation are at least 50% more effective at preventing energy loss through air infiltration. Spray foam insulation also helps guard against the growth of mold and mildew and the decay of wood. In addition to controlling temperature and keeping moisture out, it also helps in soundproofing.

Open And Closed Foam

Shown above; both open and closed cell foam look about the same.

Recently, building scientists have been conducting tests and re-evaluating the accepted philosophy on roof ventilation. The Journal of Light Construction published an article, in which Ralph Britton with the Housing and Home Finance Agency is quoted,

“Un-vented roof assemblies performed well, showing no excess moisture accumulation, while the only vented roof assemblies that performed equally well had good vapor barriers and good workmanship.”

Here in New England, there are varying opinions on the subject. Our advice: do your homework.

The idea behind venting:

The reason to vent a roof in part depends on the climate you live in. In cold climates, like here in New England, the idea is to maintain a cold temperature under the roof deck. The reason is to help eliminate ice dam issues by keeping the roof cold. In hot climates or summer weather, the venting will keep the space below the roof cooler.

Venting a roof (cold roof) versus un-vented roofs (hot roof)- the differences:

Venting a roof not only helps with heat and cold regulation depending on the season, but it also removes moisture from the structure. This can all contribute to lower energy costs, as well.

The idea behind an un-vented roof:

A hot roof is designed to hold the heat in the building completely with high R values in the insulation and an air tight building envelope.

The tighter the building envelope the more effective the hot roof. Air leaks and poor air circulation can contribute to long term trouble that can lead to moisture build up, mold, and rot.

Mechanical air handling systems are the ideal situation when it comes to hot roof installation.

If you have an existing log or timber framed home, adding insulation and ventilation can be a major challenge and expense due to demolition costs. However, it can be done from the roof side at the time you replace your asphalt or cedar roof with a new aluminum metal roof. Many times, insulation and/or ventilation can be added to an existing roof making it function the way it is supposed to.

Why Metal Roof Snow Brakes Should Be Thought About In the Spring and Summer

Tuesday, May 20th, 2014

The flowers beginning to bloom are only one of the many beautiful manifestations of the calm, tranquil, and spring-defining month of May. As the summer is approaching, we are seeing warmer and sunnier afternoons. The metal roofing industry is beginning its yearly cycle and homeowners all over New England are simultaneously looking to get a new metal roof. It has been frequently said that getting a metal roof is essential for the lifetime protection for a safe, worry-free future of a home; so, with this level of ease in mind, let’s talk about a worrisome topic that may not be top of mind this time of year: snow!

Ice Dams Review

icedam

Ice Dams

Some of the most common roofing problems we hear from homeowners across New England are almost always concerning ice, snow, and ice dams. Sure, these conditions resulting from the many winter elements are troublesome at that given time; however, you should consider the long-term damage that ice and snow can typically do to roofing and how this damage can be prevented.

Let us consider why your asphalt roofing had ice dam issues last winter. If there is poor ventilation in your roofing, heat from the house probably rose up into the attic and melted the snow that was over the given heated areas. Snow that had piled up over your unheated overhangs, such as your porch roof, did not have the same effect. When the ice on the higher parts of your roof began to melt from the heat, it probably began to seep down to the overhangs and freeze into ice. This ice could have backed its way into the roofing material and entered your structure. This is a notoriously endemic issue, and neglecting extra snow that is on your roof can cause serious internal damage of your home.

Pro-tip: If you are not investing in a metal roof, invest in a snow rake, at the very least.

Understand that any type of roofing can be susceptible to ice dams, especially when there is an environment of extremely freezing temperatures and no sun. It can happen on a metal roofing system when snow builds up from the ground or gutters and makes its way up onto the roofing system. This, however, usually is not an issue with a metal roofing system – just be cautious.

Underlayment / Roof Deck Protection

In case of any potential ice dam issues on a metal roof, find out what your hired contractor is planning on using for roof deck protection.  An “underlayment” is a type of rubber membrane, such as Ice and Water Shield, which will provide additional protection to the roof deck, not the shingles. This will protect your home from any potential water infiltration.

When the question, “Will a metal roof avoid ice dams?” is asked, the answer is, for the most part: yes! It is very rare to see an ice dam on a metal roof. In fact, it is so nonexistent that, ironically, we actually need to utilize a method that will *prevent* the snow from falling off the roof too quickly. Metal roofing has a very smooth surface. Metal roofs also have high radiant heat reflectivity, meaning that when the sun’s rays strike the roof, they reflect outward. Radiant heat passes through the snow as soon as the sun comes out, spreading throughout the entire roof. The bottom of the snow starts to become slippery, causing it to slide off of the roof very easily and quickly. Subjectively speaking, a potential issue with a metal roof is not that the snow piles up; it is that it can come off too quickly! How is this prevented?

Metal Roof Snow Brake Systems: Known as Snow Guards, Snow Rails, or Snow Fences

*Classic Metal Roofs, LLC, unlike many other metal roofing contractors in New England, includes the cost of snow brakes in every quote.

Why is it important to utilize metal roof snow brakes?

aluminumsnowbrakes

Aluminum Snow Brakes

Large chunks of snow falling off of a metal roof at once could be dangerous due to a steep pitch over doorways or vital areas of landscaping. Understand that if the pitch is not very steep, too-frequent spacing of the snow brakes could prevent snow from sliding off to too much of an extent to where it is not shedding any snow at all. In this case, or any other troublesome circumstances, a heat tape can be used on the overhangs to melt the snow. However, understand that the gutters and downspouts must also be lined with the heat tape to ensure that the melted snow can leave the roof efficiently.

There are a variety of styles for metal roof snow brakes, most of which interface very well with most products offered. Be sure to discuss with your contractor which type of snow brake will function and interface with your product most efficiently. Metal roof snow brakes can come in steel, aluminum, copper, and polycarbonate. Keep in mind that the material of the snow brake must match the metal of the roof. Therefore, an aluminum metal roof would require aluminum snow brakes. However, a stainless steel snow brake system can be used with just about any type of metal roofing system because it is nonreactive.

snowfence

Snow Fence

If you have done some research on a manufacturer’s website regarding snow brakes, here is an insider tip: the recommendations they give on spacing and placement are often angled towards generating more revenue. Based on Classic Metal Roofs’ experience, for most areas, placing the snow brakes from 12” to 18” apart is adequate. During installation, be sure that the crew is keeping snow brakes away from valleys where snow tends to collect as opposed to escape.

If a contractor neglected to install snow brakes on your already-installed metal roof, there is still hope. Though aluminum snow brakes are installed structurally due to how durable they must be to withstand heavy chunks of ice and snow, a polycarbonate snow brake can be implemented after installation of the roof in case of any possible mistake. Polycarbonate snow brakes have special adhesives which stick them to the roofing material as opposed to being fastened into the roof. The reasoning for using polycarbonate snow brakes is, because they can be done in a retrofit, this can help avoid the potential of nullifying the factory warranty of the roof. Remember, putting a fastener through a panel will typically void your metal roofing system’s warranty.

Conclusion

Pay attention to what your prospective metal roofing contractor is planning on doing and whether or not that contractor meets your criteria. Add to your written criteria the utilization of snow guards and underlayment and be absolutely sure that the contractor you’re meeting with discusses these details with you.

For more information, check out how to select a metal roofing contractor …