How Slate Roofing Weight Impacts Home Maintenance

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A slate roof is the pinnacle of roof covering choices.

Almost impervious to the elements, a properly installed slate roof can last for 100-plus years. In fact, there are slate roofs in parts of Europe that are still in good condition after 4 centuries. However, longevity is not the only factor that draws people to slate roofing — it is the timeless beauty, the undeniable curb appeal, and the extra curb appeal that slate adds to value of your home.

For starters, slate roofing will not rot, and it's the most fire-resistant roof covering on the market. It is also an eco-friendly product due to it’s long service life.

Even the most common roofing type, asphalt shingles, gets replaced about every 20-30 years, and the old shingles get deposited into a landfill. Slate roofing tiles, on the other hand, get replaced every 100 years or so, which means disposal wastes from roof replacements are reduced by ⅔ every time a slate roof is installed.

However, natural slate has its limitations — primarily in the structural requirements that must be met in order to carry the load of the slate roofing weight.

Drawbacks To Natural Slate Roofing

Slate Roofing Tile Drawbacks

1. Slate roof weight

A slate roof can weigh between 800 and 1500 hundred pounds per hundred square feet. Compare that with an asphalt shingle roof that weighs between 230 and 430 pounds per hundred square feet. That makes slate potentially 6 times heavier than asphalt, which a standard roof is not built to hold.

In fact, the normal roof is engineered to support a dead weight (the weight of the shingles and occasional snow load) of 15 pounds per square foot. A slate roofing system would need to be engineered to hold 27 to 50 pounds per square foot — a substantial difference — in order to avoid collapse.

If you are building a new home, this additional strength requirement can be engineered into the framing from the start of construction, but if you are replacing an old shingle roof that was not designed to carry the weight of slate, you will have to get a certified engineer involved in the process that can add thousands of dollars to the cost of your roof. If you decide to guess at what would be needed to brace your existing framing, you may end up with your roofing system sitting in your lap.

The additional slate roofing weight requires that you are diligent with regular maintenance checks. If you purchased a home with a slate roof already installed, you need to periodically check the roof structure in the attic to make sure that excessive bowing is not occurring in any of the truss members as a result of this weight.

2. Maintenance concerns

Slate is stone and stands up under most adverse circumstances, but it is dangerous to walk on because it can be very slippery. Not to mention, slate roofing is extremely brittle and can be cracked or broken just by walking on it. This means that maintenance must be done by experienced professionals or your entire roof could be damaged or destroyed.

It also means that maintenance costs can add up. The biggest concerns when caring for a natural slate tile roof are broken tiles and flashing that is failing. By ignoring these issues you may be allowing water to seep below the tile roof onto the wood supports below, eventually inviting wood rot that can weaken the structure and lead to a total roof collapse. Jeff Guthrie of Phoenix Roofing & Repair beliefs that "having a regular maintenance of your slate roof should be done at least twice during the fall season and right after the winter season is over." He also asserts that homeowners should "make sure to check for any damaged slates due to weather conditions and have them replaced immediately if possible," mentioning that a scheduled inspection is important to have completed every 4-6 years.

3. High installation costs

Once a slate roof has been installed, it is fairly easy to keep up with. However, the road to a complete installation can be long and expensive.

For examples, a typical slate roof can cost up to 5 times as much as a regular shingle roof. In addition, locating a sufficient quantity of slate for the roof may be difficult and it may not arrive all at once. Some jobs have experienced delivery times that extended for months while waiting for the product to arrive.

Unlike a standard asphalt shingle installation which can take 2-3 days at the most, a professionally installed slate roof can take months to install after all the materials are on the job. If there is extra support that must be added, this will also increase the cost of the job and the time needed to complete it.

Installers are difficult to locate

4. Installers are difficult to locate

Installing a slate roof is not a DIY project by any stretch of the imagination. There are special tools required and the individual slate tiles must be handled delicately in order to avoid breaking them. The tiles cannot be walked on during installation without extreme care or they will break.

While searching for an installer, you may run into roofers that say they can handle the job, but you want to be sure that they have verifiable references before you turn this job over to them. If the tiles are not installed correctly, you can experience a myriad of issues in the future that can cost you thousands of dollars in repair work and may require the roof to be redone if the mistakes are severe enough.

Is it possible to get the traditional beauty of slate roofing tile without the negative issues associated with slate roof weight and the special handling requirements required to avoid damaging the tiles?

Absolutely! (Just keep reading.)

The Best of Both Worlds: Brava’s Synthetic Slate Roofing Products

Synthetic Slate Roof Tiles

Brava Old World Slate is a beautiful synthetic slate roof tile that can be installed over most existing roof decks without any additional support.

The tiles are all matching so there is no need to wait to finish your roof until tile quantities arrive. Plus there are no special tools required, or specific handling requirements, to install the tiles.

Did we mentioned that Brava Old World Slate tiles are available in a variety of standard and unlimited custom colors—or that they are available in Class A and Class C fire rating and Class 4 impact rating for hail prone areas. Not to mention, our tiles can be walked on without fear of breakage and come with our 50-year limited warranty.

And to make things even easier, you can check out our PDFs, photos, and videos to ensure that your job is installed correctly.

Contact us today to get started on your next roofing project today. We'll help you find a contractor you'll love, and our customer service experts can provide you with free samples of our synthetic slate, shake, clay roofing tile, and provide you with a free quote as well.

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