Metal Roofing Update

Metal makes for stylish lifetime durability

These panels were used by the jillions to roof barns and other shelters are still in use today. Recycled examples with a nice layer of rust and patina are actually in high demand.

I admire homeowners who choose metal roofs for value and durability. Be concerned though if your installer only offers a one-year guarantee on workmanship. A weak workmanship warranty is a red flag about the installer so check them out.  A weak warranty is also at odds with metal roofing’s exceptional material warranties and durability. 

The industry’s Metal Roofing Alliance offers courses for metal roofing installers and contractors to make sure their work stands up to the durability of the metal material, and the test of time. By using proper installation practices your contractor should be offering workmanship guarantees that are more commensurate with a lifetime roofing material.

Use compatible accessories

An expensive metal roof can be ruined by using cheap or incompatible trim, fasteners, and accessories. Using galvanized materials or fasteners on a galvalume roof, for example, can cause irreparable corrosion and oxidation, compromising the quality of the panels and shortening a metal roof’s life.

The cause is poor training, planning or laziness because it only costs a small amount more for the proper trim, fasteners, and accessories that are compatible with the metal roofing material. The long-term assurance of reduced call-backs… and even better, satisfied customers is well worth the trouble.

Install with water runoff in mind

Use roof flashings and curbs made from aluminum or stainless steel that are most compatible for metal roofs. Galvanized flashing is inferior, won’t last as long and can actually cause corrosion damage. If using galvalume flashing, minimize and check seam welding as this can melt the material’s protective coating.

Use well thought-out flashings and under/over curbs. Make sure you plan for proper clearance in order to give water some room to run off and avoid pooling (a good rule of thumb is a minimum of 12 inches between panel ends and the diverter on the upslope end, and 6 inches between the curb’s sides and panel seams). For big curbs with a heavyweight load, be sure you have proper structural support underneath. Demand use of curbs around chimneys, caulking alone will not hold over time to prevent leaks.

Penetrations

For metal roof plumbing penetrations, do not use standard residential pipe jacks or those made for membrane roofs. Use a pipe boots made to last, from galvalume or aluminum. Move the penetrations to miss panel seams and avoid blocking the flow of water. If other trades need to make penetrations in the roof (like HVAC), be sure they are supervised by the roofer and coordinate the location and method so that only proper techniques and materials designed for metal are used.

Summary

Contractors with the proper training should be confident enough in their product to offer workmanship guarantees that make sense. The value of a fine metal roof deserves that.

New shingles over bad? No!

What’s a roof-over?

Image showing roof edge with many layers
Multiple roof layers

In the roofing industry, a common cost-cutting practice is to install a layer of new asphalt shingles over an old roof. This practice is called a roof-over and it costs less because there is no removal or disposal of the old roof. It also avoids having to install new roof sheathing and waterproof flashings, thus saving even more money.

Sadly, shingling over an existing roof is still permissible by the building codes in most areas of the country and many roofers consider it a common industry practice.

To the average unsuspecting homeowner, the finished shingle-over roof may look OK, and the price will certainly be enticing. But any experienced roofer can tell without even stepping on the roof that it has multiple layers of older material underneath. The surface of the completed roof may appear good, but the problems can arise in areas that cannot be seen.

Most responsible, professional roofers are aware of the shortcomings of this practice and will not even provide the option to their customers. As a homeowner, if you are offered this, you should know the risks.  Skipping the tear-off stage, means you will not really get a new roof.

Only consider doing so if the risks are fully disclosed and it is the only thing you can afford.

Please note, the intention of this article is not to police the roofing industry, but rather to educate the homeowner on how to make a good decision for themselves when it comes to roofing options.

New roof work scope

During a quality roof replacement, a good roofing crew will close windows and skylights, then install protection in the attic and around landscaping areas to prevent debris from fouling or damaging those areas. Then they will remove the old layers of shingles and roof paper and haul everything off-site to be disposed. Stripping the roof down to decking, allows an accurate visual inspection and assessment of the condition of the wood structure under the shingles. Without removing the surface material, it is impossible to really tell what’s going on underneath, especially if there is no attic area.

Structural condition

Most roofs being replaced will be more than 20-30 years old, so many will have decking (sheathing) issues somewhere. Removing the old roof allows visual assessment of the structure and sheathing. Exposing the wood framing and sheathing will reveal any dry rot, or defective framing or ventilation all of which should be repaired before the new roof goes on.

Flashing is important

Flashing is a critical part of any roof. This is the material used to provide waterproofing protection at roof/wall junctions and intersections. All penetrations through the roof or places where the roof meets walls, or changes directions and at edges must have properly installed flashing to guarantee water tightness.

Most flashing material used on homes is made of galvanized sheet metal which has a lifespan of about 25-30 years. Which happens to also be the average life expectancy of the roofing. Since proper flashing can only be installed on the first layer of roofing. Subsequent layers of roofing will be relying on old flashing that is beyond it’s expected life to provide key waterproofing functions. The only way to resolve this problem is by using lots of caulking. Unfortunately, caulking has an even shorter lifespan than metal flashing and tends to dry out, crack and become non-functional after a fairly short exposure to the elements. All bad news.

Over-weight roof

Image showing sags in roof structure from weight
Sagging roof surface and ridge

Extra layers of roofing mean extra weight. Older homes built before the 1950’s commonly used 2×4 rafter/trusses spaced 24” apart. The decking consisted of “skip” sheathing which referred to 1×4 boards laid across the rafters with 4” spaces or “skips” between the boards. This worked great for wood shingle or shake roofs as it improved durability by allowing more air to circulate under the roof material. 2×4 rafters, skip sheathing and wood shingles make a very lightweight roofing system.

Then asphalt shingles were introduced. Asphalt shingle roofing is about twice as heavy as dry wood shakes. Asphalt shingle roofing also needs a solid sub-surface so the “skips” in the structure were either filled-in or a layer of plywood was applied over the top. This added more weight. Now if you add another layer of asphalt shingle roofing material over the top, you have likely exceeded the original design specs for the roof structure by about 100%. These older 2×4 rafters often don’t have the strength to support extra layers of shingles. You will see this plainly as sagging areas either along the ridge or on the main roof surfaces.

Cost /value

image of roof area with obvious weak sagging areas
Sagging roof structure
Removing, or demolishing existing roof materials isn’t cheap. It takes time and is hard, dangerous work. This danger means roofers have one of the highest rates for workers compensation insurance in the industry. Old roof removal or “tear-off” adds $100 to $200 per square (a square is 10’x10’ or 100 square feet) to the cost of a new roof. On a 20-square roof that would be $2,000 to $4,000.
If the old roof is torn off, there will be more costs for protecting the attic space, skylights, landscape areas, new flashing (i.e., drip edge, starter strip, valley and roof/wall flashings, ice-and-water, etc.), and then of course the disposal fees.

Skipping the tear-off stage will of course save money, but homeowners need to know that in doing so, they will not really get a new roof. Roofs tend to fail and leak primarily at the flashing areas and not on the large roof planes. Failing to replace the flashings means the roof is more likely to leak at those areas.

Warranties

For all the reasons noted above, skipping the removal of the old roof should never be an option.
Respectable roofing companies make tear off mandatory and most material manufacturer warranties like The GAF Master Elite certification and Golden Pledge warranty would be voided if the new roof isn’t installed onto decking. CertainTeed’s Five Star warranty—good against defects for 50 years—requires that the shingles be installed on “a clean, dry deck.”

Start Fresh

image showing rotted section of roof framing under removed roof surface
Roof structure dry rot

Starting fresh means  the old roof is completely removed. Your new roof can then be installed on wood framing that is sound and rot free. A new roof will come with all the new industry advanced elements, such as breathable membranes and longer lasting flashing that are integrated into a system that enables products like a 50-year shingle to perform at their best.

Installing a second layer roofing denies the homeowner of these benefits and advancements. Ice-and-water shielding, drip edge flashing and new and better ventilation systems are not incorporated into a roof-over. A new roof, properly installed, should be a long-term asset and a real attraction to potential or future buyers. An asset that can be incorporated into the asking price.

Summary

Homeowners need to know their risks in order to make good choices, and for reputable roofers, explaining tear-off and price differences is about providing the best possible service for their customers.

Resources

Roof Systems

Image of nice Spanish tile roofing with nice view
Spanish Tile Roof

Caring for Cedar Shingle and Shake Roofing

Wood roofing is naturally organic and stunningly beautiful in appearance.  Most wood shingle and shake roofs are made from western red cedar because of its exceptional properties, including reasonable cost, availability, straight grain, stability, relative light weight (low density), impenetrability to water, and decay resistance. Attributes like this have made it highly sought after by architects and homeowners for many years.  See also

This resistance to decay is derived from natural oils and substances found within the structure of the wood. Other wood species, like redwood and cypress, have similar properties and are sometimes used; but decreasing supplies and higher costs, make them scarce these days.

Decay resistant or not, because cedar is an organic material, it requires some attention and care to counteract natural decay. A well-maintained cedar shingle or shake roof should last 35-50 years. The actual life is affected by local environmental conditions like humidity and wind, salt and sun exposure but the factor that most shortens the life of cedar roofs is inattention.

Image of worn out wood roofing.
Wood shingle roof at end of life

For a long life these roofs must breath. Any dirt, debris or leaves that accumulates on the surface or packs into the spaces between the shingles must be removed. Heavy tree branches can cause damage to wood roofs and restrict good airflow. Pruning will help, while reducing the debris and discouraging the growth of moss, another surefire killer of wood roofing. Any moss and fungus must be removed. Installation of a copper wire along the ridge and every 10’ across the surface of the roof will help control moss if your home is prone to it.

I have heard people say not to walk on a wood roof for fear of damage. That is BS. Frankly, it sounds like a good excuse to not get up there and clean it. Walking on the surface of a wood roof is necessary to clean it and if done properly (step lightly and only on the flat areas not the ends) will have little to no effect. Close inspection from the roof level means that a shingle found missing or split, can be quickly and easily repaired.

As much as we try, even perfectly maintained wood roofs will eventually wear out. The wear comes from exposure to the sun (which dries and cooks the outer surface). Rain (which washes away the sun damaged areas) and wind (which blows particles against the roof). These elements work to slowly erode the material till there is little left but paper-thin strips. Shingles and shakes erode with the softer material between the growth rings going first. A 50-year old wood roof will have shingles that have almost completely eroded away except these hard ring strips.

Wood roofs are stunning to look at when new, but you can forget about trying to keep them looking like that. Cedar will darken no matter what you do. The change in color is rather rapid, occurring within the first year of exposure (under more severe conditions, within several months). Gradually, the silver gray will change to a darker, more graphite gray, then to a brown/black color indicating the colonization of the surface by micro fungi that complete the initial phase of the weathering process.

Wood rapidly attracts water to its surface. When this happens, the wood swells. As it dries and the moisture content decreases, it shrinks. This repeated wet to dry cycling causes the development of compression and tension stresses; these, in turn, cause microscopic cracks to develop.
Over time, these cracks grow larger and larger, caused by additional wettings or by freezing and thawing. The cracks also trap water and allow wood-rotting organisms to penetrate deeper into the wood.

As the water penetrates deeper, the wood becomes slower to dry after rains. With increased moisture, the wood-rotting organisms prolong their destructive activity and damage more wood material than would occur during normal weathering.
As the roof continues to age, the surface and any sharp edges from manufacturing are eroded by abrasive particles carried by wind and water and by the action of sunlight. Birds and insects also continue to slowly degrade the surface and the thicker butt edge.

Fire is an enemy of wood roofs so they are certainly not appropriate for areas that are in potential wildfire danger. All wood roofing materials can be had in fire retardant varieties. Do not apply any coating that claims to be a fire retardant. Shingles that are certified as fire-retardant will be permanently impregnated and protected from fire.

There are any number of products that claim to prolong the life of a cedar roof, and there is little agreement about their effectiveness. Even the Cedar Shingle & Shake Bureau doesn’t recommend anything. They simply suggest that if you’re going to put them on, you should at least enlist the services of a reputable contractor with a solid record locally. According to the bureau, any suitable products will be formulated specifically for wood roofs, and contain a UV inhibitor, a water repellent, and/or an EPA-registered wood preservative. Most shakes have an impregnated fire retardant, so any preservative must be compatible with it. Also, any kind of “sealer” will certainly cause damage to the cedar material since it needs to breathe?

Pressure washers are not recommended because cedar is a soft, low-density wood. Misuse of high-pressure systems can detach shingles or erode many years of wear in moments, even though the roof may look like new. Pressure washing can also drive water deep beneath the shingles and into the attic and structure below.

If you are lucky enough to own a wood roof, congratulations! Now pay it back by taking good care of it.

Resources

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Roof Types


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Wood Roof Treatments-Yes or No?

We often get asked how to extend the life of wood shingle or shake roofs. These questions usually come at the end of the roof’s life when unfortunately, there really isn’t much that can be done. By that time, it is too late for saving and most homeowners are just not prepared. When looking at a large estimate for a roof replacement, many homeowners go into shock and become desperate. And that is precisely when they are likely to fall prey to sales pitches offering treatments to “extend” the life of the roof “for a mere fraction of the cost of new.”

These “miracle” treatments usually include a wood brightener application, a pressure wash cleaning of the roof, some spot replacements of missing shingles, and the topical application of some unknown preservative. These can make the roof look better and come with enticingly whopping 5 year (or more) guarantees.

I don’t recommend these offers because 1) Applications of wood brightener and pressure washing can further damage old roof materials and drive water into the attic space. 2) Cedar needs to breath, so topically applied preservatives that are safe for cedar will last less than a year; and if they do last longer (sealers etc.) can cause further damage to the cedar material. 3) Alternatives excluding 1 and 2 above are better and less costly.

It is good to remember that the primary reason for the roof in the first place, to prevent leaks and protect the rest of the structure from damage. In a sense it is sacrificial in nature. So, if your roof is at the end of its life and you can’t afford a new one, here are five things you should do:

  1. Thoroughly clean the roof. This allows you to see where any damage is that needs repair and removing debris will allow rainwater to more easily flow off the surface.
  2. Replace any missing or badly worn and damaged roof shingles.
  3. Make any other repairs (at flashings, caulking, roof jacks or vents) needed to prevent leakage. An inspection of the roof structure from the attic will tell you where any leaks have been occurring.
  4. Take the money you saved from NOT buying a Miracle Treatment and start paying into a new annuity fund to pay for replacing the roof in five years.
  5. Repeat this every year for the next five years till you can afford to replace the roof.

When the time finally comes, use this guides section on roofing to properly install and take care of it.

Resources

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Roof Types




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Thatch Roofing

Thatch has to be one of the most recognizable and yet least knowable of all roofing types. These roofs have been featured in movies and are associated with many an illustrated children’s fairy-tale. Still, homes with thatch roofing are a mystery to Americans because they are essentially non-existent in the US.

thatch roofing
thatch roofing

Much of the building technology used today is a result of our ancestors simply having to quickly and cheaply create shelter for themselves. The use of thatch for roofing is certainly an example of this. The use of organic materials like leaves, palm fronds for roof covering goes back thousands of years. Thatch use evolved because it was readily available, cheap and lightweight. People of old, built their own homes and though they may have been amateurs with unsophisticated methods, the constructions were still done with a high degree of skill, mostly developed through trial and lots of error.

The use of thatch grew steadily during Norman times and this popularity remained until devastating fires wiped out much of London from 1077 through 1202. Finally, in 1212 authorities decided that something had to be done, and the first building code in London was enacted. The Ordinance of 1212 essentially prohibited the use of thatch. That date marks the beginning of the decline of thatching and the birth of the making of tile for roofing.

Thatching continued to decline all through the 1800’s as production of Welsh slate increased on a massive scale. The French wars and the two world wars all had a negative effect on the industry as well. Since the 1970’s though Thatching has seen somewhat of a rebirth to a point that now it is considered a potential growth industry albeit on an extremely custom basis.

The common materials used for thatch are Norfolk water reed and winter wheat straw. Sedge is used for ridge material. Sedge grows in the same areas as water reed and is maintained as complimentary crop.

Installation techniques vary according to the material being used and to regional traditions and styles of the trades folk. Like many tradecrafts, specific methods and techniques are handed down to family members and workers through experience. Even so, basic procedures call for starting the work at the eaves and progressing up the roof plane with overlapping courses to finally terminate at the ridge. Schools in the UK offer six-month training programs for adults to learn the art of thatching. Successful graduates will come away with about 80 percent of the knowledge needed to become a master thatcher.

thatch roofing
thatch roofing

The material is fastened to the timbers and framing of the roof structure. The thatcher must lay the straw in a manner that will shed rainwater from all areas of the roof without it penetrating to the interior and framing. There are few rules and each craftsperson must choose methods to suit the conditions presented to him or her. For this reason, thatch roofs are unique, and no two roofs are ever the same.

Properly installed and maintained thatch can last from 50-80 years. Natural wear and tear occurs from a number of external forces like rain, wind, frost and birds. Most of these can be overcome by good maintenance efforts by the homeowner. Preventive maintenance is necessary in order to get the full value from a thatch roof. Window cleaning, chimney cleaning and painting has to be performed carefully in order to avoid damage to the thatch. The roof should be inspected annually, and any damage found should be corrected immediately.

Thatch lasts longer when kept out of the overhang and shade of trees. Sometimes, sprays may be needed to prevent deterioration from fungus and parasites. Birds can be especially damaging to these roofs and repairs should be made when problems are found to prevent nests from being built.

The most obvious problem with thatch is its susceptibility to fire. While there is no treatment that can be applied to render thatch non-combustible, there are some products on the market that can provide a temporary, limited degree of protection. Smart prevention is the key. Modern installations require a layer of barrier foil be applied to the framing prior to being overlain with thatch. Besides helping to make the structure more fire resistant, the foil also acts as barrier to thermal radiation to help keep the interior cool.

Thatch is one of the most aesthetically unique materials for roofing one can consider. If you are intrigued by an unusual, hand crafted roof with fairy-tale appearance, thatch may be just what you are looking for.

For more about thatch roofs and roofing I recommend reading a copy of Thatch by Robert West. A complete guide to the ancient craft of thatching.

Resources

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Roof Types

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Metal Roofing

I just installed a new standing seam steel roof on my home and it is awesome! If a new roof is in your future, you would do well to consider metal. A metal roof can provide significant benefits for you and your home.

History

Metals have been used for roofing material for a long time. Copper shingles have been found on architectural ruins dating as far back as 300 years BC. Lead has possibly been used for an even longer period. Industrial age mass production methods included taking sheets of galvanized steel and roll forming them into stiff corrugated panels. These corrugated steel panels were used by the billions during WWII then salvaged afterward to roof barns and other shelters. Many are still in use today. Recycled examples with a nice layer of rust and patina are actually in high demand.

Image of contemporary home with metal roof and wood siding
Standing seam metal roof

Durability

Metal roofing is extremely durable and is known to endure most types of severe weather, including snow, rain, hail (dents) and sun. It is tough enough to stand up to significant abuse without failure. The coated, standing seam material used on my house came with a 50-year warranty. I have in the past had many kinds of roofs, including wood shake, wood shingle, composite asphalt, and tile and none have come with warranties like that. I’m pretty sure I won’t be around to see that warranty run out, but I like having it nonetheless.

Materials

Metal roofing is available in steel, galvanized, zinc, copper, aluminum and alloys with trade names like Galvalume and Zincalume. The metal material can be roll-formed into sheets or stamped into designs that emulate shingles, tiles or shakes. Finishes can be applied to achieve just about any appearance and with the right type of finish, you won’t need to worry about the color fading over time.

Installation

Installation of metal roofing is fairly easy but still requires knowledge and skills. It is especially important to properly waterproof around penetrations, skylights, chimneys and roof/wall junctions. I have heard installers say that new metal roofing can be installed on top of your existing roof, but I cannot imagine why you would want to do that. If you can afford a metal roof, you can certainly afford to do it right. The material is lightweight and won’t cause problems to your existing roof structure. This fact can save you some significant money during the installation phase.

I admire homeowners who make the choice to invest in metal roofs because of their durability, so be concerned if some installers only offer a one-year guarantee on workmanship. This is at odds with metal roofing’s exceptional material warranties and promise of durability. TheMetal Roofing Allianceoffers courses for  metal roofing installers and contractors to make sure their work stands up to the durability of the metal material, and the test of time. By using proper installation practices your contractor should be offering workmanship guarantees that are more commensurate with a lifetime roofing material. Here are some examples:

 

Use compatible accessories

An expensive metal roof can be ruined by using cheap or incompatible trim, fasteners, and accessories. Using galvanized materials or fasteners on a galvalume roof, for example, can cause irreparable corrosion and oxidation, compromising the quality of the panels and shortening a metal roof’s life. This is caused by poor planning or laziness because it only costs a small amount more for proper trim, fasteners, and accessories that are compatible with the metal roofing material. The long-term assurance of reduced call-backs… and even better, satisfied customersis well worth the trouble. 

 

Install with water runoff in mind

Use roof flashings and curbs made from aluminum or stainless steel that are most compatible for metal roofs. Galvanized flashing is inferior, won’t last as long and can actually cause corrosion damage. If using galvalume flashing, minimize and check seam welding as this can melt the material’s protective coating. 

Use well thought-out flashings and under/over curbs. Make sure you plan for proper clearance in order to give water some room to run off and avoid pooling (a good rule of thumb is a minimum of 12 inches between panel ends and the diverter on the upslope end, and 6 inches between the curb’s sides and panel seams). For big curbs with a heavyweight load, be sure you have proper structural support underneath. Demand use of curbs around chimneys, caulking alone will not hold over time to prevent leaks.  

 

Penetrations

For metal roof plumbing penetrations, do not use standard residential pipe jacks or those made for membrane roofs. Use a pipe boots made to last, from galvalume or aluminum.

Move the penetrations to miss panel seams and avoid blocking the flow of water. If other trades need to make penetrations in the roof (like HVAC), be sure they are supervised by the roofer and coordinate the location and method so that only proper techniques and materials designed for metal are used.

 

Contractors with the proper training should be confident enough in their product to offer workmanship guarantees that make sense. The value of a fine metal roof deserves that.

More

Here are even more benefits for homeowners who choose this material.

Energy

A metal roof system will help lower your energy bills. During the summer, it can reflect radiant solar heat that helps cut cooling costs. During the winter season, it will shed snow and ice off the top.

Functionality

Most metal roof varieties only weigh 50 to 150 pounds per 100 sft. This is the reason it can be installed over the top of old roof systems. There’s no need for additional structural support as the material is so light.

Sustainable

Roof metals, zinc, steel, copper and aluminum are some of the most durable and recyclable materials on the planet. If you decide to get a new one, you can even recycle it when you’re finished so there will be little waste at the end of the roof’s useful life.

Choices

The variety of metal roofing available caters to customers with different preference in price and style. You can choose between zinc, aluminum, copper and galvanized steel in many shapes and colors. Whatever you choose, you can count on unmatched longevity.

Aesthetics

Best of all, metal roofing looks great! A metal roof can make any home more attractive and an attractive home is a more valuable home. Plus, it’s much more fun to come home to every night. This alone is a great reason to choose a metal roof.

Summary

The up-front cost of my standing seam metal roofing was slightly higher than lesser roofs but when factors like durability, maintenance, life expectancy, energy savings, low weight, ultra-sustainability and good looks were considered, it was a total bargain.
The only problem we had was with the protective film applied by the factory. Because of scheduling issues, the roof material sat on site for several months prior to installation. When it came time to remove the protective film, it would not come off so some of the metal panels actually had to be replaced.

Once installed you will have a beautiful roof to protect your home for 50 to 70 years and perhaps even longer.

Resources

Image of nice Spanish tile roofing with nice view

Roof Types

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