What Should Go Under My Metal Roofing
When aluminum roofing came on the scene, it was found that it, too, could be installed over battens. This was because of its high strength / low weight ratio. Installation over battens was cheaper than putting down dimensional lumber to create a smooth surface. Also, on steep roof surfaces, the battens provided a ladder of sorts for roof access. This was in the days before various scaffolding and other equipment was commonly available.
The other option for installing metal roofing calls for a solid deck to be in place and then the roofing is attached to it. A solid deck originally meant dimensional lumber installed tightly together. Today, it often means plywood or oriented-strand board .
Standing Seam Metal Roof installed on solid decking.
As metal roofing systems were developed in this country, starting originally with hand-formed panels and then machine-fabricated corrugated sheets, the focus was on systems which could be installed over battens.
Over the years, a problem has developed with metal roofing installed over battens. That problem is the accumulation of condensation on the back side of the roofing panels. If this condensation accumulates too much, it quickly causes a dangerous situation for toxic mold and other problems in the attic space.
Can You Put Metal Roofing Directly Over Shingles
It depends on the circumstances, but in many cases, you will be able to install metal roofing directly over shingles. Metal is surprisingly lightweight considering how strong it is, so adding a metal roof over shingles will not significantly increase the overall load on your homes structure. However, you may not be able to if you already have multiple layers of shingles. Youll also need to check with your local building and zoning departments to make sure they approve.
Round Up The Materials For An Under Deck Drainage System
Rune bought corrugated fiberglass panels at a home center to use for his under-deck roof. The panels he used are 26 in. wide and 12 ft. long. He attached the panels with special roofing screws that have hex heads and neoprene washers for sealing. Youll find these screws where steel or fiberglass roofing is sold. You could also use galvanized steel or plastic roofing panels and install them the same way. Rune screwed treated 2×4 purlins to spacer blocks to support the panels and provide the necessary slope .
Gutters arent required, especially if the water drains onto your lawn. But if the water falls onto the patio, gutters can prevent splashing. Rune chose PVC gutters because theyre inexpensive and easy to cut and install. If you decide to install gutters, youll need lengths of the gutter, gutter straps, end caps, a downspout outlet, downspouts and special glue to join the sections.
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Final Thoughts On Synthetic Vs Felt Underlayment
So, is synthetic or felt paper underlayment the best choice for you?
Well, it depends.
For help deciding between these two options, ask yourself these questions:
- How long do I want the roof underlayment to last? How about the actual roof?
- Does my/my customers budget allow for an expensive underlayment?
- Will my/my customers underlayment be exposed to long periods of sun or heat?
- Do I want to be able to buy my underlayment at a big-box store?
- How concerned am I about fire resistance or having a Class-A fire rating?
At Sheffield Metals, we understand how important it is for you to choose the right underlayment right from the start, which is why recommend and offer synthetic underlayment options from Sharkskin, a trusted supplier providing value and long-term underlayment solutions.
Does My Metal Roof Need An Underlayment
The simple answer is yes, your roof does need an underlayment. But there are some caveats that go with that, and it depends on a variety of factors.
Traditionally built homes will need an underlayment. If your home is built with joists, insulation between those joists, and sheathing, then an underlayment is needed before you put on a metal roof. Basically any house in Montana, from Billings to Philipsburg to Zortman is going to be built this way. But there are parts of the home that differ.
A covered patio may not need an underlayment. If your patio has open beam architecture, and is designed to have a roof consisting of structural metal panels then you dont need an underlayment.
If your metal roof is going on top of asphalt shingles, then there is already an underlayment, and it likely doesnt need another. Keep in mind, however, that expansion and contraction of the shingles could cause damage to the back of the metal over time. Its for this reason that Beartooth Metal Roofing in Billings always tears off the old shingles before applying a new roof.
There are some metal manufacturers that require an underlayment in order to keep the warranty valid. Some go even further and require a self-adhering underlayment throughout the entire roof deck. It is a more expensive method, but it will last a whole lot longer and be a whole lot more weather proof.
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Ready For Your New Metal Roof
Metal roofs are the perfect way to make sure that your roof looks amazing, lasts forever, and protects your home from whatever the weather can throw at it. Beartooth Metal Roofing serves the areas within a few hundred miles of Billings, Montana. So if you live in Cody, WY, we can put a metal roof on your home. If you have a cabin near Cooke City, Montana, we can get a metal roof on your cabin. If you have a luxury mansion along the Stillwater River near Absarokee, MT, we can make it look perfect.
You get the idea. Give us a call at to schedule a time for your new metal roof.
Metal Roofing Does Not Attract Lightning
You might think that a metal roof will attract lightning, but this is not borne out by facts or statistics. According to a technical bulletin from the Metal Construction Association, “Metal roofing does not in any way increase the risk of a lightning strike.” Not only that but if metal roofing does happen to get struck by lightning, it is less combustible than conventional roofing materials such as wood shakes or shingles.
As the bulletin asserts, “Because metal roofing is both an electrical conductor and a noncombustible material, the risks associated with its use and behavior during a lightning event make it the most desirable construction available.”
The reason that metal roofs do not attract lighting is simple: lighting seeks a path to ground, which is why trees, telephone poles, and other such structures tend to attract lightning. Metal roofs are isolated structural components, with no direct path to ground inherent in their design. Hence, there is no scientific reason for lighting to strike a metal roof any more often than it strikes an asphalt shingle roof.
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Measure The Roof Valley
Measure each roof valley from the lower end to the upper end and multiply the result by two, which provides nailers for each side the valley. Count the number of penetrations, such as duct vents and pipe risers that go through the roof. Include 4 feet of stripping for each, which translates to 12-inch-long nailers at all sides of a penetration.
Obtain one-by-three framing lumber for the nailers based on your measurements and calculations. Include 1 pound of 8d framing nails for every 100 square feet of the roof.
Spacing Of Furring Strips For Metal Roof
When installing a metal roof over an existing roof, insulate the spaces between the wood strips with rigid insulation to prevent condensation before installing the roofing. You also need to add furring strips. Correctly measure the spacing of furring strips for a metal roof to further decrease condensation. Twenty-four inches is a common spacing of furring strips for a metal roof.
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The Benefits Of Metal Roofing
Architects, contractors, and building and homeowners select metal roofing for its longevity, durability, and energy-saving qualities.
- Metal roofs are durable and can last up to 75 years.
- They can withstand strong wind gusts, flying debris, and hail.
- They are a Class A fire-rated roof covering.
- Metal roofs with rustproof coatings do not crack.
- They decrease the roof temperature, compared to asphalt roofs, which may extend the roofs service life.
Lay And Secure The First Metal Panel
When laying the metal, you will need to start from the bottom corner of the roof and work across. After you have finished each row of panels, you will then need to start a new row that overlaps the old row by at least 4 inches.
You can think of this process as moving across the bottom of the roof and then progressively getting higher and higher until you reach the peak.
When you start with the first metal panel, position it so that it overhangs the edge by at least 4 inches. Now slide a washer onto a 1 ½-inch wood screw and use your screwdriver to secure it to the plywood of the roof.
As a rule of thumb, you want it to be tight enough to hold it in place, but not so tight that youâve dimpled the metal. Then, add screws approximately every 8 inches along the outside edge and bottom of the panel.
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Can You Use Standard Ice & Water Barrier Beneath Metal Roofing
Most manufacturers of fully adhered roofing underlayment, or ice and water shield, offer their product in two major categories.The problem turned out to be – you’ve likely guessed it – the ice and water installed by his roof contractor. Its worth taking the time to make sure that you use the right type under metal.
Roof Safety And Tools
Always keep your safety in mind before doing roof work. Do not work on a roof in windy weather or you risk injury. Exercise extreme caution when working near overhead power lines at a roof.
Use a tool belt that has a hammer loop to hold nails, a measuring tape, chalk line and a hammer when installing the wood stripping to keep everything handy. Experienced do-it-yourselfers can use a nail gun with 8d nail clips instead of a hammer and nails.
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Felt Paper Underlayment Disadvantages
DOESNT LAST AS LONG The biggest issue with felt paper underlayment is that it doesnt last as long as a synthetic underlayment. Longevity varies dramatically from manufacturer to manufacturer since this material is most popular with shingle roofing, most felt paper is warranted for the lifetime of a shingle roof . Felt underlayment will break down and weaken over time, especially if exposed to high heat, sun exposure, or frequent temperate fluctuations.
HIGH-TEMPERATURE PROBLEMS Another problem that could arise with felt underlayment is that it doesnt respond well in high heat environments. Asphalt is a semi-solid form of petroleum and an oil-based product, so it is more susceptible to high temperatures breaking down the material, drying out the oil, cracking, and ultimately degrading prematurely.
LESS EXPOSURE TIME Felt underlayment should not be exposed to sunlight for an extended period of time. How long it can be is dependent on how much asphalt/oil is in it and how quickly the material will dry out and not perform properly. According to Construction Pro Tips, some roofing felt can bubble, buckle, and wrinkle within just 24 hours of UV exposure. These imperfections created in the felt can even translate through shingles or metal panels to create an unsightly surface.
Which Type Of Underlayer Is Right For Your Metal Roofing Installation
It depends!
Specifically, it depends on your local weather conditions. That means variables such as:
- Climate
- Rain
Additionally, it also depends on your needs.
For example, if your property needs even greater insulation than sarking can offer, we might start looking at alternative underlayers to give you the protection you need.
As a general rule, however, the vast majority of metal roofing installations in Melbourne are best served with sarking. While our city has a reputation for wild weather, most of the time, the climate is mild enough that you dont need to spring for a more specialised underlayer.
Our metal roofing team in Melbourne begins each job by taking stock.
We inspect the site and plan, as well as local conditions this allows us to choose the best components for your roof, including:
- The right gauge and brand of metal roofing
- The best type of metal roofing
- How it should be attached to your property
And of course, that also includes the most suitable type of underlayer too!
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Prevent Condensation Before It Occurs
Condensation is not a natural force thats beyond your control. Its a matter of science, and understanding what factors are causing excessive humidity within your structure.
These factors can be influenced before the construction process begins, and some can be altered once the building is in place. Its a balancing act, and you will likely cheat the system using methods like insulation and membranes like DripStop.
Whatever you do, for the well-being of whats inside your structure, be careful not to underestimate the corrosive powers of condensation. Water is the stuff of life, but left to its own devices, it can also be the stuff of drained bank accounts. Treat any condensation problems with the respect it deserves.
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Snap A Square Reference Line
- A square reference line is important for installing roofing panels evenly. Use the 3-4-5 method to establish a reference line 90 degrees to the eave.
- First, make a mark along the eave three feet from the corner. At that mark, measure four feet toward the ridge. Then, from the original corner, measure five feet and mark where it intersects the second mark.
- Snap a line from the first three-foot mark through the intersection of the second and third marks. Since the Getaway roof is larger, I measured to 21 feet, 28 feet and 35 feet to make my square reference line.
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Can You Spray Foam Insulation On A Metal Roof
absolutely! Some building owners dont realize that spraying over metal is an option. If you have a roof leak with your metal roof, installing spray foam over top can close all those leaks and provide you with more R value. In fact, spray foam has a 100% chemical adhesion across the entire metal roof.
Copper And Zinc Roofs
For example, a copper roof could potentially last for over 60 years and even over 100 years. Its also a very soft metal, making it one of the quietest metal roofs. However, this quality also makes it very susceptible to damage from things like hail.
Although, being soft, it is more likely to dent than end up with a puncture. Of course, with its long-lasting, super-quiet perks comes a hefty price tag. Depending on the quality, you could pay anywhere from $14 to $25 per square foot.
Zinc roofshave similar benefits to copper as well as a similar price tag.
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Severe Hail Can Ruin Metal Roofing
Although metal roofs are considerably more durable and maintenance-free than asphalt shingles and other forms of roofing, they are not indestructible. There is one weather condition in particular that bodes ill for metal roofing: large hail. Aluminum and copper, in particular, can be susceptible to denting when hailstones approach golf-ball size. Steel is harder and fares better in hailstorms, but if you live in a region where such catastrophic hail can occur, be aware of this when considering metal. Pea-sized or even dime-sized hail is rarely a problem, but hailstones larger than this have been known to ruin metal roofs.
Then again, large hail can also destroy an asphalt shingle roof, so if you make sure to have good homeowner’s insurance that covers such storm damage, there is no reason not to install metal roofing.
Pros And Cons Of Metal Roofs For Your Home
Whether you’re buying a home with one or thinking of installing, here’s what to know.
Whether you’re putting a roof on a new home, or your existing roof requires a total makeover, there are many materials available. But no matter what roof style you have, metal roofs can be an attractive option because of their longevity, minimal maintenance and energy efficiency. Material choices include steel , aluminum, copper, zinc and tin. Product types are vertical seam, pre-formed panels and granular coated panels. Style choices allow you to have the look of shingles, slate, tile, shakes or vertical panels. Make sure your metal roofing product is tested, labeled and listed with a testing organization such as UL, FM Approvals or Intertek to meet rigorous wind, fire and impact resistance rating requirements. Please also remember that installation can vary from geographic location, manufacturer guidelines and as a result of local building code requirements.
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Can You Install Metal Roofing Directly To Plywood
Metal roofing is affordable, durable, and easy to install. But deciding where and how to install it requires some knowledge of building materials and their potential pitfalls. Do you have to build a sub-structure for metal roofing, or can you install it directly onto plywood?
When installing metal roofing,you should always use a roofing felt layer between the metal roofing and the plywood. It is also advisable to use a slip sheet to protect the felt. You may be able to layer it on top of your current roofing, but you need to check with your local building codes before doing so.
Lets go over how to correctly install metal roofing over plywood. You will also find out what to look for when determining if the roof is stable enough to have metal directly installed over it.
