Installing metal shingles is a more difficult do-it-yourself project than installing other types of shingle material. The proper alignment of the metal shingles requires accuracy and an enormous attention to detail. Metal, unlike fiberglass and asphalt, expands and contracts in response to temperature changes.
This expansion and contraction due to changes in temperature does not affect the installation process but is something that should be noted. Improper installation of metal shingles leads to thermal movement. Thermal movement causes the shingles to move and eventually allows the roof to leak and become damaged. This can be prevented by following these steps precisely.
You may want to consider working in a smaller area, like a porch overhang, in order to get a feel for the installation process.
Step 1: Preparing the Roof for Shingle Installation
Clear all old roofing materials and debris from the roof. The surface must be clean and perfectly flat to work on. Any holes in the planks should be patched with flashing tape and replace the worn out boards with plywood.
Step 2: Install the Drip Edge
Install the drip edge around the edge of the roof, secure using roofing nails. The drip edge should overlap at the corners and any overhang material can be trimmed off using the tin snips.
Step 3: Install the Shield and Underlay Material
Lay the ice and water shield by starting from the drip edge. Installing the ice and water shield will help reduce build-up during times of extreme temperature changes.
The underlay material for a metal roof is a polymer-based material designed to reduce and prevent slippage. Apply the material in rows, allowing it to overlap every few inches. Staple in place with a stapler or hammer tacker as it is unrolled and cut any excess material using your utility knife.
Step 4: Install the Metal Shingles
Starter shingles should be laid at the drip edge, nailed down with roofing nails. Next, lay the shingles, working from the lower corner of the roof upward. Fasten the shingles to the roof using the nail clips designed specifically for metal shingles. You should stagger the pattern of the shingles in order to prevent gaps from lining up and allowing water to accumulate underneath.
Step 5: Install Roof Ventilation
Hot air needs to be able to escape from the attic in order to prevent a build up of heat. Cut holes at the top of the roof with a circular saw. After the vent holes have been cut, cover with the polymer underlay and cut with the utility knife to reveal.
At the top, place the roofing vent over the holes and attach to the roof using roofing nails. The roofing shingles for the vent go over the top and fasten with clips.