Ballpark estimate: $10 to $75+ per square foot (plus installation)
If you live in a historic home, you may be fortunate enough to have a beautiful roof made of slate. Slate roofs are aesthetically pleasing and also are quite desirable from a practical standpoint because they can last a century or even longer (compare this with more modern roofs that have a lifespan of two to three decades). As a result, many people who have high-end newer homes may also decide to invest in a roof made of slate. Just keep in mind that in return for the longevity, slate roofs also require much upkeep.
While slate roofs can be beautiful, they are also expensive. This is because installing slate is a real art, as well as a serious undertaking, and needs to be handled by a very experienced company. In fact, if you have slate installed by someone who is not an expert at this job, you could end up with serious—and expensive—problems down the road. The reality is that slate is very delicate and so it can break easily if it isn’t handled properly. In addition, if your slate roof isn’t laid properly, it won’t protect your home and your possessions and you could end up with some serious water damage. Further, slate tiles can become damaged over time and can be difficult and expensive to repair.
Why Choose a Slate Roof?
The reason people choose slate roofs are because they are aesthetically pleasing. They come in different colors and add a warm, elegant touch to a home. This is the material that is used on most castles and mansions. It’s also the most durable roof that exists and it’s fire proof as well. The normal quarter-inch slate can last over 100 years. Also, because slate is more durable than asphalt (a more common roofing material), this makes slate more environmentally friendly that since every 30 years or so, asphalt has to be stripped and thrown into landfills. So people who opt for slate can help to minimize this waste.
Factors Affecting the Cost
Some of the factors that are considered when pricing a slate roof include the type of slate selected, the pattern used for the installation (some methods use more slate per square foot), the design of the roof, the height of the building, and the slope. Also, you should keep in mind when replacing an existing slate roof there could be damage to the wood and flashing under the slate. The flashing usually is copper and this means that you will need a very experienced coppersmith to handle this part of the job. (Usually a slate company will have a coppersmith on staff to install new copper.) In addition, if you’re putting a new slate roof on top of an old roof, you may have to support the roof further in order to handle the weight of the slate, since slate is very heavy and could cause structural damage if it’s not properly supported. If you need to have your roof reinforced, it can really jack up your bill, costing as much as $10,000 before the slate roof even goes on.
When you get a price from the slate roof contractor, you’ll need to know the cost of the slate, the price for installation, copper flashing, if applicable, and any trim work that is visually seen that needs replacing. Also, the roofer should supply the copper nails, which are the correct nails because they will never rot. Remember, on a roof that you will replace with slate there may be repairs that are not seen when the project is quoted. Therefore, the price could be increased with unexpected repairs that come up during the job.
Shopping for Slate Roofs
When shopping for a slate roof, the most important factors include the contractor and the quality of the slate. Make sure the slate being installed comes from a reputable high-quality quarry. Buying locally will save on shipping costs and the product will arrive sooner. The National Slate Association lists sources to access new and also salvaged slate roofing tiles. You can also find a directory of slate roofing contractors through the National Slate Association’s website, as well as through the website of the Slate Roofing Contractors of North America Inc.
Cost for a Slate Roof
Before you can determine the cost of a slate roof for your home, you need to know the size of the roof. While you might assume that the size would be the same as the square footage of your home, in fact the roof square footage is completely different so you’ll need to have it measured by an expert.
Then there’s the variation in slate quality, color, thickness, exposure, as well as whether it’s graduated or not.
To understand how the costs might play out, figure that an average home has a roofing size of 25,000 square feet. At the low end of the price scale, a slate roof can start as low as $10 per square foot for material and can go up as high as $75 per square foot for very high-end slate. This price likely won’t include removing the existing roof or reinstalling or replacing copper flashing at this low price point. On the lower end of the price scale, this is thinner slate that is more typical. The more expensive slate is typically thicker and has more unique coloring and variations. The copper for flashings can run about $2 to $3 per foot.
The cost for the labor to install the slate roof can be another $2,500 to $7,500, depending on what’s involved. This price should also include the removal of your existing roof. If your roof has a steep grade, it can add as much as another 20 percent to your job, while having an unusual design or pattern done can also increase the costs by as much as 20 to 30 percent more.
Considering the Location
Keep in mind that where you live can also impact the costs of your job. In large cities with a higher cost of living, slate and installation may cost more, while in smaller or more rural areas, you may get a better bargain. On the flip side, also keep in mind that in cities that have many older buildings where slate is common, you may have more artisans who specialize in installing slate, so the competition may work in your favor, since you can price out the job and find the best fit and expertise to meet your needs most effectively.