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How To Put A Metal Roof On A Deck

Four: Install The First Metal Roof Panel

How to install a metal roof? | Direct-to-deck | Steel Canada Roofing and Siding Limited

Once youre ready to start installing the metal panels, youll work from left to right. Start at the bottom of the roof. Use the chalk box to snap a vertical line ¼ from the roofs rake edge and square with the eave.

The rake edge is the part of the roof that sits above the house. It helps water flow off the roof and onto the ground without running down the side of your home.

Place the first panel into position on the bottom, left side of the roof. Overlap the roofs edge by one inch and work up toward the ridge. Use the 1 ½ galvanized metal screws to secure the panel to the decking. Place a screw about every 12 to 16 inches apart.

Should I Put A Roof Over My Deck

A roof over a deck is a great option for people who want to use their deck rain or shine. Or, for those who live in very sunny and hot areas, it makes outdoor living more bearable by providing permanent shade.

While a roof over a deck may not be ideal for all geographies or homes, having a covered space on the exterior of your house is practical for a variety of reasons:


  • Potentially requires digging new footings for roof

Is Underlayment Necessary For A Metal Roof

No, underlayment for a metal roof on a shed is not necessary. A properly installed metal roof does not need a second waterproof layer on a shed. If you intend to heat your shed, however, then you will need underlayment to protect against condensation damage.

Neglecting to use underlayment isnt a bad choice for shed owners unless you dont install your metal roof properly. In that case, your roof sheathing will rot, decay, and eventually have structural failure if you dont rectify the problem in a timely manner.

Tar paper or Tyvek wrap can be used, too. Tar paper is weather resistant, absorbs moisture and will let it evaporate over time. The drawback to tar paper is that if you have a constant leak, it will become too saturated and destroy the wood beneath it.

Housewrap, such as Tyvek, is a more durable alternative to tar paper but more expensive. It is waterproof but not a vapor barrier, so youll still get condensation on the underside of your metal roof. However, the wrap will still largely keep the water from getting onto your roof sheathing.

The best underlayment for a shed metal roof is waterproof self-adhering membrane. Once you apply it, you can rest easy. This membrane is like having two roofs on top of each other it is durable, waterproof, serves as an air barrier and holds up well in extremely hot and cold climates.

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Install The Metal Roof Panels

Installing the metal roof panel depends on the type of metal roof product you have, but start at the edge and make sure your first panel overlaps the existing edging by an inch, if applicable. Otherwise run your first panel flush with the rake edge of your roof and 1 over the eave if you have gutters 3 if you dont have gutters.

The top of the metal panel should be flush or no more than an inch below the peak of the gable roof. Screw in your panels according to manufacturer directions. See above for rules about how many screws to use our rule was 80 per square of roofing.

If screwing into the rib of the metal panel, be careful to not screw too far and dent the rib and overly compress the neoprene washer. If you have metal panels overlap at a rib you can also use metal lap screws, which connect the panels but do not go into the sheathing. These are also used for roof edging that go over metal roof rake ends.

If your metal roof product says you need mastic tape and sealant to put beneath the panel seams, then go ahead and apply. Do it slowly as the tape can be difficult to work with.

Chances are your final piece of roof will need a lengthwise cut to fit the width of your shed roof. If so, a circular saw with a metal cutting blade works really well. You can also use tin snips but cutting long pieces with snips is awkward and arduous.

Materials Needed For Roofing Work

How to Install Corrugated Roof Panels Under a Deck

Materials needed for adding a roof over your present deck will depend on the size of your deck and also on if you have enough headroom under the deck roof. For smaller decks, roof can be laid out like shingles would go on a house.

Larger once will require more support beams and braces. The tools youll need for adding a roof will vary depending on the materials used for installation. Still, shingles are usually nailed with a rubber mallet/hammer combo, while lightweight materials can be screwed in with a power drill.

If you plan to build a roof over the original decking or boards, youll need to get new roofing material and ladders or scaffolding if the height requires it.

If you plan to remove the old decking and replace it with a new or stronger one, check with local building codes before you cause any damage to your existing structure

Your town might require an inspection by a certified professional if you are using the roof over your deck for access to a second floor of the home.

Once inspected and approved, you can remove all old materials and replace them with a new deck. After that, you can build a roof over your deck. You will also need to check that the nails are fully extracted and dispose of them properly .

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Can Your Deck Support A Roof

A deck alone can never support a roof. For instance, you cannot rely on your deck joists or beams to support your roof as well as your deck. Load tables for joists and beams consider 10 psf dead loads, which is the amount of lumber used on the deck alone not a deck and a roof. Therefore, adding a roofs weight onto a deck negates the structural integrity of the deck.

A deck roof will need to be supported by posts and a beam. The posts will need to be on concrete footings, deep enough to go beyond the frost line in your area. A beam will connect the posts and will be sized according to the local building code. The rafters will support the roof itself and connect the beam to the house.

If you already have appropriately sized posts supporting your deck, there is the possibility of integrating existing deck posts with the roof posts however, in most cases, the deck roof will require new footings.

Can You Install Metal Roof Over Shingles

Yes, you can install a metal roof over shingles. The shingles will act as underlayment for your metal roof and provide a solid foundation provided they are not completely disintegrating.

Some will opt to place battens and underlayment over existing roof shingles. The reason for this is to ensure proper connection of the roofing panels to the roof. Old asphalt shingles may not provide enough holding strength for part of a roof screw, so screwing battens to roof rafters or trusses on top of shingles ensures the integrity of the metal roof.

Read Also: Should I Replace The Screws On My Metal Roof

Which Steel Roof Deck Is Right For My Project

Trying to match an existing steel roof deck? With D-MAC Industries steel deck identifier tool, you can find the right steel roof deck for any project! Simply line up the guide to any existing steel roof deck to see which product is right for your project. If at any point you need assistance identifying which steel roof deck is right for your project, our team will be happy to help. We have extensive experience guiding our customers through any decking project, and can make roof deck recommendations that are tailored specifically to your needs.

How To Install Metal Roofing On A Shed

Rebuilding a Deck and Adding a Metal Roof Pt.3 | How To | MY DIY

Metal roofing has taken over in my neighborhood. It seems like everyone is replacing their shingle roof with metal, and no wonder it looks really good. However, when I heard how much it cost a friend of mine, I realized it might be out of my price range. But then I immediately thought of my shed. Which got me thinking about how you would install metal roofing on a shed.

Installing a metal roof on a shed requires a solid deck beneath or battens, but only if the interior will not be heated. Install the fascia and leave edging pieces. If using roof underlayment, it will go over the top edges of the edging. Install metal roof according to manufacturer instructions. Use flashing to cover raised intersections, such as on a gable roof.

Metal roof installations can vary widely due to the wide variety of manufacturers making metal roofing panels. While most home reno big box stores may only sell one or two brands, each will have its unique way to install. They will also have proprietary edging and flashing pieces, too.

In this article, well go over how to install a standard corrugated metal roof on a shed, from the materials youll need to a finished roof.

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How To Build A Deck Roof: Attach The Purlins

Plan to space the 2×4 purlins parallel to the house and 3 ft. on center. To provide drainage, the panels should slope toward the outside edge of the deck about 1/4 in. per foot. If the span under your deck is 12 ft., for example, the purlin at the outer end of the deck should be 3 in. lower than the purlin along the house .

First, mark all the purlin locations on the deck joists. Install the purlin along the house and the outer purlin. Then stretch a string between them. Measure down from the deck joists to the string at the other purlin locations. Those measurements will give you the widths of the spacer blocks.

Cut the spacer blocks and screw them to the bottom of the joists at the marks. Then attach the remaining 2×4 purlins by screwing them to the spacers.

Types Of Roof Decking

Metal deck can be used in a variety of ways, but one of the most common uses for metal deck is for roofing. When you are sourcing metal deck for a roofing project, it is important to know which type of deck that you need. This guide will help you understand the different types of roof decking, and when to use them.

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Advantages Of Metal Roofs

Metal roofs offer many benefits, including:

  • Longevity. Metal roofs can last 40-70 years, depending on the material. Traditional asphalt roofing materials have an estimated life expectancy of roughly 12-20 years.
  • Durability. If installed correctly, some metal roofs can sustain wind gusts up to 140 miles per hour, will not corrode or crack and may be impact-resistant . In addition, metal roofs don’t need the periodic costly maintenance that other roofing materials often require. However, they should be inspected periodically to make sure no repairs are required.
  • Safety. Metal roofs will not spark and ignite into flames during a wildfire or lightning strike.
  • Energy efficiency. Metal roofs reflect the suns UV and infrared light rays that contribute to roof surface radiant heat, which can result in a 10-25% reduction in cooling costs.
  • Environmentally friendly. Metal roofs not only have 25-95% recycled content, depending on the material used, but are also 100% recyclable at the end of their life as a roof. In contrast, most shingle tear-off waste ends up as part of the building-related waste stream up to 20 billion pounds per year.

How To Install Metal Roofing To Plywood

How To Metal roof for cheap

Installing metal roofing over plywood is less time-intensive and more affordable than a shingle roof, but there are still several steps you should take when installing a metal roof to plywood to ensure that your roof does not leak and will stand the test of time.

Follow these steps when installing metal roofing on top of plywood:

  • Inspect the existing roof. If the plywood on your roof has not been recently installed, there could be rotten or warped plywood. You must first check for soft spots and warped wood.
  • Repair existing damage. If you discover wood rot or warping, replace the damaged sheets of plywood. This can be labor-intensive, and you may be tempted to cover those areas, but you will be dramatically reducing the life of your metal roofing if you do. Remove the damaged sheets and replace them with new plywood.
  • Replacing rotten wood is critical because dry rot will spread. Adjacent areas of healthy plywood may eventually become rotten, and then the screws you have placed there will not hold. Warped wood should also be replaced. Warping signifies that the wood is prone to rot and will prevent you from laying the metal roofing flat. Wind will be able to get underneath the roofing and pull it off your roof.

    Be sure to use plywood that is thick enough. The plywood or OSB you use for a base underneath your metal roofing should be at least 7/16 inch thick. This thickness will ensure that the wood is sturdy enough to hold the screws in place and support the metal roofing. .

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    Should I Cover My Deck In The Winter

    Its important to cover your deck in the winter to protect it from harsh winter weather. You can choose between a permanent roof and a temporary tarp, but you may want to build a roof to invest in the long-term. If youre wondering how to put a roof over an existing deck, get in touch with your local roofing experts. They can either give you advice or complete the job for you.

    Does A Deck Add Value To A House

    Although a deck can help increase the resale value of a house, many homeowners dont choose to install one for purely financial reasons. Decks add value in other ways, including whats considered the joy factor, which helps improve the livability of homes. Installing a new deck may seem like a big expense, but it can be worth it in the long run.

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    Type N Metal Roof Deck

    Type N roof decking is a 3 deep steel roof deck thats suited for applications where it is desirable to space the supporting members as far apart as possible. Often used in gymnasiums and other large areas, Type N steel roof deck is perfect for minimizing the number of long span structural members. D-MAC Industries supplies high-quality deep rib steel roof deck in gauges of 16, 18, 20, and 22. If you are not sure which steel roof deck meets your needs, one of our experienced team members will be happy to help you.

    My Metal Roof Has No Deck Under It Is This Normal

    Adding a roof under a deck

    We bought this house over 10 years ago, we were young and naive, apparently. It is a coastal cottage or key west style home- hardiplank siding with a metal roof. We live on the gulf coast- cold weather is never an issue, when you go in our attic and look up you see daylight. We have open eaves and no leaks but the metal is attached directly to the trusses. Now we want to sell the house and I am concerned it will not pass an inspection because of the roof. I think the house has hurricane straps so whoever built it did something right. Can anyone tell me if this is a usual practice. I know heat rises and our power bill is not astronomical even with the 14 year old insulation in the attic floor. Also, if it does need decking in order to pass an inspection, will the current roof have to be removed?

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    Drive Screws Just Right

    • Fastening the panels just right is the key to a watertight roof. Here is what you should know:
    • At the eave, place screws on both sides of every rib and lined up to go through the foam closure strip.
    • Each row should be spaced no more than 24 inches with one screw at each rib on the overlapping side.
    • Start at the bottom, fastening across the panel in rows, working toward the ridge.
    • Drive screws to seat flat on the roof a crooked screw wont seal.
    • Dont over-tighten or under-tighten. Tighten just enough to compress the rubber gasket to the edge of the screw head, not past it.
    • Clean up any metal shavings or burrs right away. They will rust.

    Purchase All Of Your Materials And Tools

    After youve measured your roof, the next step is to purchase all the materials and tools youll need for installation. Again, refer to our list of tools and materials above, but now you will know more accurately how many materials youll need to purchase based on your roofs measurements.

    Metal Roofing Sheets: These are usually available in three lengths and can be purchased in either the sheet form or in pre-cut lengths.

    Metal Roofing Shingles: They come with a variety of widths and have an option for round shapes used on steep pitches.

    Galvanized Steel Frames: These frames are available in different sizes and are installed first to support the metal panels.

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