In addition to standard slate-look shingles, Authentic Roof makes decorative Beaver Tail shingles (with rounded corners) and Mitered Edge shingles (with clipped corners). My client’s roof had decorative bands of red Beaver Tail shingles integrated into the design.
Like natural slate, synthetic slates have slight color variations, so bundles must be mixed before installation.
To keep the decorative rounded slates in alignment with the field slates, the author uses a spacer block.
Inexplicably, the Beaver Tail shingles are slightly narrower than the square shingles. As a result, I couldn’t rely on the molded spacing tabs if I wanted to maintain the vertical layout. Instead, I made spacer blocks a little thicker than the tabs. We inserted them between shingles so we could match the layout on the square slates. Other than the spacing issue, the decorative shingles install just like the square-cut version.
Curves. The barrel-vaulted porch on this house was originally supposed to have a soldered copper roof, but this was eliminated from the budget. Luckily, Authentic Roof slates can be warmed up with a heat gun and shaped to conform to a curved surface. It was pretty easy to mold the slates to follow the porch roof’s convex and concave curves.
Authentic Roof slates can be heated up and molded to fit such curved shapes as barrel-vaulted roofs.
Hip and Ridge Caps
The manufacturer’s cap slates look a lot like standard slates except that they have a crease molded into the back. Once the shingles are heated with a heat gun, the shingle can be folded along the crease to match the roof’s pitch. By late October — when we were capping the ridge — the mornings were quite cool, so to save time we’d preheat a stack of shingles with a torpedo heater and finish up by heating individual shingles with the heat gun.
In cold weather, the slates are stored in a warm area and heated to above 50°F so they’re easier to cut.
Cap slates — which have a ridge channel molded into the back — are warmed with a heat gun.
Then bent into shape (bottom left) and nailed into place at a hip or the ridge.
The caps can also be installed over a ridge vent, as long as longer nails are used. The manufacturer recommends shingle installations over vented roofs only.
Cooler temperatures complicate Authentic Roof slate installation. The manufacturer suggests keeping the slates at a minimum temperature of 50°F, but sometimes that’s just not possible.
When the thermometer dropped below 40°F, the slates were tough to cut, so we took to warming a stack with a kerosene space heater. I would then make a few cuts at once while the shingles were still warm enough to cut easily. This became especially important for the many cuts required at the hipped cornice returns that flanked the gable ends.
I had figured that the job would take about four weeks if I worked with one or two helpers. It ended up taking about twice that long. This was partly because we were working with a new product; but also, the early-winter weather slowed us down. Twice, the half-completed roof was buried in snow. It was critical that we waited for the roof to dry because the shingles are extremely slippery when they’re wet or snowy.
On my next synthetic-slate roof installation, I’m assembling a bigger crew to speed installation and we’re making the starters and caps ahead of time. I charge about $240 per square to install synthetic slate — about $80 more per square than I charge to install architectural asphalt shingles, but as much as $160 less per square than real slate.
Roger Ouimette is a general contractor in Champlain, N.Y.