Slate roofs aren’t cheap, but they are attractive and extremely durable. In order to install solar panels properly you need to anchor them to the roof structure. That means going through the slate layers. But individual slates are brittle, and replacing them can be a challenge. So, can you install solar panels and keep the slate roof?
You can install solar panels on a slate roof. Installing solar over a slate roof is a bit complicated, but the durability of a slate roof means that solar panels can still be economical.
This article will talk about slate roofs and the challenges involved in installing solar panels on them. Then I’ll show you how contractors have overcome the difficulties. There are some architectural issues that are especially important when slate roofs are involved. But in the end, the sheer durability of a slate roof can make the operation worthwhile.
Why A Slate Roof Is Great For Solar Panels
Slate is a natural stone that is quarried at locations throughout the United States and throughout the world. When used for roofing, slate is cut into thin, flat pieces that function a lot like roof shingles. They are installed in an overlapping pattern, with sticker slates installed lower down near the troughs and thinner slates installed nearer to the peak.
Slate has been used as a roofing material in the United States as far back as the colonial period. Slate roofs offer many advantages. Slate is fireproof and very resistant to water damage. Slate roofs can also be very attractive. They are essential to many building styles that were popular in the late 19th and early 20th centuries.
Slate roofs can be heavy. A building with a slate roof will need a solid structure to support the weight of the stone. And slate can be tricky to install. Usually slates will be cut to consistent widths but that isn’t always the case. And slate pieces can be brittle, so workers will need to move carefully and avoid breaking slates as they are installed.
But once it is in place a slate roof is incredibly durable. A typical slate roof will last at least 60 years — while a standard shingle roof will need to be replaced after 15 years. Some slate roofs have held up for 120 or even 200 years.
How Solar Panels Are Installed Over a Slate Roof
The challenges with slate roofs come from the unique nature of the material. Before installing solar panels, it is necessary to set up brackets and anchor them into the roof structure. That means anchors need to go through the slate into the frame of the roof.
Slate is tough when dealing with the elements, but the thin stone pieces can be brittle when dealing with nails or drills — you can’t just hammer nails or drive screws through slate the way you might with asphalt shingles. Slate can also vary in texture and color depending on where it was quarried. Finding a match for slates that are damaged or replaced can be difficult.
Installers have dealt with this difficulty in one of two ways. One involves carefully removing individual slate pieces and replacing them with artificial materials reinforced with metal.
The other involves drilling or cutting through slate pieces, creating room for anchoring brackets. In either case, the goal is to disturb the slate as little as possible. But the work can be painstaking. You can expect to pay more for materials and labor.
The Durability of Slate and the Economics of Solar
If it is done well, though, the results can be very attractive. And the durability of slate roofs can make solar panels economical in spite of the difficulties.
Solar panels typically last 25 years. That’s longer than many roofing systems, which means homeowners sometimes have to replace their roofs underneath the solar panels. With slate roofs lasting more than a century, that’s a lot less likely to happen. You might want to update your solar panels down the road, but when that time comes you won’t need to replace the slate roof.
There are a couple of complications that you should keep in mind. As long as the solar panels are up, any slate pieces that are altered or replaced will be hidden by the panels. If you decide later on to remove the solar panels, you may find it difficult to repair or replace those slate pieces.
A Caution about Historical Designations
Also, you should be aware if your home has any historical value or carries a historical designation. This applies to any home but is particularly relevant for slate roofs because of the age of many slate-roofed structures and the distinctive styles associated with slate roofing.
Slate roofs aren’t always just a practical choice; they can be an architectural statement too. The roof is often a very prominent part of a building, and that is frequently the case with slate. If your home has unique historical or architectural value, you may want to think about how and where to install solar panels. In particular you should pay attention to how the solar panels will change the appearance of the structure.
A historical designation may complicate things further. You may need to check on rules relating to modifications. There are few indications of open hostility to solar power among preservationists, but a too-obvious installation might become a bone of contention with local authorities.
Some roofs are easier to install solar panels on than others, but there really isn’t a common roof type that is incompatible with solar power. The unique properties of slate do complicate the installation of solar panels a little bit, but solar contractors have developed several solutions.
Slate roofs are very distinctive architecturally, so you will want to think about how the solar panels will affect the appearance of your home. But the durability of slate roofing makes solar installations very economical over the long run.