How to install Metal Roofing and Flashing details.

Have you considered the amount of money you could save if you buy all the necessary metal roofing materials and install a metal roof yourself? It is amazing how many people think that metal roofing installation can be easily done because, when you watch the professionals perform an installation of a metal roofing system they do make it look easy. However, installing metal roofing correctly does require knowledge of the system, understanding basic roofing principles and being comfortable using the tools required in metal roofing.

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

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.

• 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 roofing fall protection

Stage 1. Roofing Tear off vs. OverTop Installation

Ask yourself, has this roof been leaking for a while? If the answer is yes, then you could have some roofing 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 shingle and the deck seems to be in good shape than you can leave it in place and roof overtop if you are planning to install an interlocking metal shingle roof. If you want to install standing seam roof, then you may want to do a full tear off, because asphalt shingle could cause unequal lines and dents in standing seam panels overtime.

The tear off is going to be the messiest and most physical part of all work especially if you have more than 1 layer of shingle. I have had the pleasure to strip as many as four layers of shingle 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 into and adhere to the roof deck. Needless to say it took forever to strip that roof, but it was worth it for the homeowner because, there was some serious roofing deck damage that needed to be addressed. Also, it is generally not recommended to have over two layers of roofing material on any roof and many States have regulations specifying the maximum number of roofing shingle layers that a roof may have.

• Stripping tool / showel
• Good Pair of working Gloves
• Tarp of sufficient length
• Respirator or Face Cover if you are sensitive to exessive dust

Roof Tear off – Ready for Action

Roof Decking Waterproofing

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 over 50 years, it is important to use a good quality metal roofing underlayment that will help ensure that your roof decking lasts as long as your metal roof does.

In cold climates with a lot of snow and ice built up, it may be a good idea to install one roll width of ice and water at the eaves and valleys of the roof. The roofing underlayment can then be installed with 6 inch overlap all the way to ridge.

Ice and Water installed at the eaves, followed with underlayment 6 inch overlap

Metal Roofing Installation

There are many different types of metal roofing systems, but standing seam is becoming one of the prominent systems of choice when it comes commercial and some residential roofing projects. Standing seam consists of sheet metal roofing panels joined side by side and attached to the roofing deck with concealed fasteners.

Preformed Standing Seam panels

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.

The Gable flashing gets installed along the gable 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.

After our first metal panel is installed, we use a system specific metal cap that goes around and enwraps 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.

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.

Notice that upper portion of the roofing panel has a vertical a 90 degrees vertical bent to prevent wind driven rain, snow and ice from getting underneath the standing seam metal roofing system.

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