How to Install a Standing Seam Metal Roof & Flashing Details

Have you ever considered the amount of money you could save if you were to buy all the necessary materials and install a metal roof — all by yourself? — Well, this DIY feat does sound tempting, but read on before you decide to jump all in…

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As a professional installer it never ceases to amaze me just how many people think that metal roofing installation can be an easy feat, all because it just seems so easy and straight forward when you watch the professionals perform the installation. They do know how to make it look easy, indeed! 🙂 However, installing metal roofing correctly does require a basic knowledge of the system and how to properly employ all the flashing components such as end-wall, and z-bar, along with a thorough understanding of the basic roofing principles, and being comfortable using all the tools required to install the system correctly.

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Since most ordinary homeowners do not have all the necessary know-how or significant knowledge of basic roofing principles, along with experience of working on an actual roof, all day in the sun, with the sweat pouring down the face as you work on flashing all the dormers, chimneys and roof vents, or shingling away for hours on end and doing it right, taking on the installation of a metal roof over your home is not something that I would easily recommend to even some of the most seasoned do-it-yourself enthusiasts.

But, if you are still curious as to what a typical standing seam installation process may entail, then read on to learn what it takes to professionally install a standing seam metal roof, which is one of the most popular styles in residential metal roofing.

Learning Objective:

Reading this guide will not make you an expert installer, but it will help you better understand the basic roofing principles and fundamental concepts required for a successful metal roofing project.

Chances are that a typical homeowner who has done some successful do it yourself projects in the past will not be able to take on installing a whole new metal roofing system for their home, but perhaps this information will help you should you decide to put a metal roof on a garage or a small tool shed.

Standing seam metal roof installation video:

Understanding Roofing Hazards:

Before we can talk about the steps to install a metal roof, we have to touch upon critically important, yet often overlooked safety considerations. Each year a great number of fatalities happen in the field of roofing due to the falls that can happen to the best and most experienced roofers. For this reason alone, it is wiser to let the professionals install you metal roof, rather than attempting to do it yourself.

Recommended Roofing Safety precautions that we use on our jobs:

  • Always have at least two people working in case someone needs to call for help
  • Know how to and always use a fall arrest system that is properly anchored into the stud on both sides of the ridge using appropriate screws
  • Use safety caution tape to mark the areas where you could accidentally drop tools or materials
  • Know how to use and always use safely placed and secured ladder that is safe to operate
Installers using fall arrest safety ropes and harnesses
Installers using fall arrest safety ropes and harnesses

Stage 1. Old Roof Tear off vs. an Over-Top Installation

Should you tear off the old shingles?

Ask yourself, has this roof been leaking for a while? If the answer is yes, then you could have some roof deck damage such as rotten boards or plywood that you may want to replace before installing a new metal roof. If you only have one layer of asphalt shingles and the deck seems to be in good shape, then you can leave the old shingles in place, and install the new metal roof overtop, but only if you are planning to install a metal shingles roof.

If instead, you want to install a standing seam roofing system, then you may want to do a full tear off, because asphalt shingles could telegraph their line especially under heavy snow loads. There is also risk of asphalt shingles puncturing through the underlayment and scratching the underside of metal panels due to thermal expansion and contraction of metal.

The Tear Off:

The tear off is by far the messiest and most physical part of all work, especially if you have more than just one layer of shingles. At some point, I have had the “pleasure” to have to strip as many as four layers of shingles on one of the roofs we worked on, and the best part was that there was no tar paper underneath, which caused asphalt to melt and adhere to the roof deck. Needless to say, it took forever to strip that roof, but it was certainly worth it for the homeowner because, there was some serious deck damage that needed to be addressed.

Note: It is generally not recommended to have over two layers of roofing material on any roof, and building codes in many states limit the maximum allowed number of roof layers to two.

The tools and equipment required for a Tear off:

  • Roof stripping tool / shovel
  • Good Pair of working Gloves
  • Tarp of sufficient length
  • Respirator or Face Cover if you are sensitive to excessive dust
  • Sun and Safety Glasses
Roof Tear off - Ready for Action
Roof Tear off – Ready for Action

Roof Deck Waterproofing

Roofing Underlayment:

Before a metal roof can be installed, we have to install the water barrier, which will act as an additional protection underneath the metal roof. Such a water barrier is designed to protect the roof decking from water that occurs from condensation due to temperature differences. Because a metal roof can last well over 35-50 years, it is important to use a good quality, breathable roofing underlayment that will help ensure that your roof decking lasts as long as your metal roof.

Ice and Water:

In cold climates with a lot of snow and ice built up, it may be a good idea (and is probably required by your local building code) to install one raw width (3 to 6 feet) of ice and water at the eaves and valleys of the roof. The underlayment can then be installed with a 6 inch overlap all the way to ridge.

Ice and Water shield installed at the eaves, followed by a roofing underlayment, with a 6 inch overlap
Ice and Water shield installed at the eaves, followed by a roofing underlayment, with a 6 inch overlap
Ice and water installed at the eave
Ice and water installed at the eave

Installing Standing Seam Metal Panels:

There are many different types of metal roofing systems, but standing seam is becoming the metal roofing system of choice when it comes commercial, industrial and many residential metal roofing projects. Standing seam consists of sheet metal roofing panels joined side by side and attached to the roofing deck with concealed fasteners. The connecting point where the two separate metal panels meet forms a vertically pointed rib or a seam that is one inch to inch and a half high.

A typical standing seam panel can be approximately 12, 16 and 19 inches wide. The panels can be roll-formed at the job site, or at your local roofing materials supply warehouse. Sheet metal panels can be made from .032 – .040 aluminum, 24 Ga. Galvalume coated steel, G-90 Galvanized Steel, Zinc, or 16oz – 20oz copper.

standing-seam-panels

Minimum Roof Pitch

Most residential standing seam roofs will require a minimum roof pitch of 2:12. Some manufacturers have roofing systems that require a minimum of 3:12 roof slope for standing seam installations. In general, the greater the slope of the roof the better, as standing seam is a water-shedding system and relies to slope and gravity to shed away any rainwater, moisture, and snow.

Unlike its close cousins, corrugated metal and R-panels or ribbed panels, standing seam is a hidden or concealed fastener system. — Each panel should be secured / attached to the roof deck by the manufacturer-approved screws or nails. Standing Seam panels overlap in a side by side fashion with each overlapping panel hiding the fasteners that hold the previous panel in place.

Standing seam metal panel being secured with concealed fasteners
Standing seam metal panel being secured with concealed fasteners

Installing the Starter or Eave Trim

installing-drip-edge-details In this step we will need to use metal sheers to cut the necessary length of the starter trim. The starter trim gets attached by the special screws every 10 to 12 inches on center. Note, the screws can be obtained from the system supplier. Install drip edge / starter trim against eave / fascia trim of the roof. Lay out your roofing underlayment over the fascia trim, so that water that may form due to condensation does not collect underneath the drip edge.

starter-trim-installation

Installing the Gable Flashing and Starting with the first panel:

The gable flashing gets installed along the gable rake in the similar way to starter flashing. Once the gable flashing is set in place we can install our first vertical sheet metal panel that comprises standing seam system. In our case we are working with a snap lock standing seam roofing system with concealed fasteners. Our first panel gets attached over the gable trim. We use the flat lip pliers to bend and secure our first panel over the gable and the starter trim.

Installation of Sheet Metal Roofing panel over the Gable flashing
Installation of Sheet Metal Roofing panel over the Gable flashing

After our first metal panel is installed, we use a system specific metal cap that goes around and enwraps the gable trim and the outer edge of the first metal panel, which is what secures holds them together on the outer edge of the system as seen in the picture above.

Installing Standing Seam Metal panel over the starter and gable flashings, and using concealed fasteners to secure it to the roof deck

Thus, the first panel gets secured around the starter and gable flashing and attached with the screws to the roof decking using special holding brackets and concealed fasteners.

metal panel bent-in at the top for the Z-bar flashing

Notice that the upper portion of the panel has a 90 degree vertical bent to prevent any wind-driven rain, snow and ice from getting in at the ridge level.

In Conclusion

Since this was an introductory guide to the basics of standing seam metal roof installations, we purposefully left out more technical details such as Z-bar flashing, end-wall, and valley flashing details, however, they are covered in the video above, if you like to learn more about the components that go beyond the basics. You may also be interested in learning more about another type of metal roofing system that is just as reliable, features concealed fasteners, but is also easier to install and less expensive than standing seam.


Learn about Installing Metal Shingles below:

Did you know? There is also an equally reliable and long-lasting metal shingles roofing system that costs less than standing seam and is easier to install?

metal-shingles-roofing-installation

Without a doubt, a standing seam roof is quite difficult and technically-challenging system to install, especially if you have no prior training or experience installing metal roofing, but there is also a simpler-to-install system called metal shingles, which looks much like the conventional shingles, except that it is far more durable, energy efficient, and longer lasting. If you are interested in learning how to install metal shingles roof, then I would recommend that you check out this metal shingles installation guide from 150points.

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2 comments

  1. I have a asphalt roof that i have installed solar panels to. I have six feet from the panels to the end of the roof, the snow slides down the panels and builds on the roof. I would like to install a metal roof over the asphalt shingles to allow the snow to slide the last six feet off the roof. Do you have a product that will slide under a row of asphalt shingles to attach the metal roof to, so I can have a metal roof the last six feet of the asphalt roof. Hope I explained this in a way you can understand.

    Thanks, Rich

    1. Hi Richard,

      The product you are referring to is called ice-belt. It’s comprised of standing seam panels installed in way that you described. Your best best is to find an experienced standing seam metal roofer or ice belt installer. You can learn more about the cost of ice belts on here.

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