Should I replace my roof before installing solar panels?
If your roof needs repairs, removing and reinstalling solar panels is an added expense you want to avoid.
A big part of the cost of a home solar installation is in the labor. An installation requires a multiple person crew, and a bucket truck to move equipment up to the roof.
Costs can vary quite a bit from installer to installer, but according to a government study of the solar industry, installation labor on average is 11% of the total cost of a residential solar system.
This means that if the gross cost of your system was $20,000, the cost of labor for the day or two it takes to install the panels will be in the ballpark of $2,200.
That also happens to be a pretty good estimate of what it will cost to remove and reinstall your solar panels if you need to do a tear-off roof replacement. If you roof needs a full replacement, the panels will have to come off, and you will need to hire a solar installer to do that work.
This means that one of the most important things to think about before installing solar panels on your roof is to evaluate its condition and number of serviceable years it has left. In large part, that will depend on the type of material.
Metal roofs are more resilient than asphalt shingles, which is why they come with long warranties. A 40 year warranty is pretty typical for a standing seam metal roof, but metal can last a lot longer than that. Often, it’s the paint that fails first rather than the underlying metal. If you have a metal roof in good shape, go ahead and install solar panels on them.
Whether the material is clay, slate, or concrete, one of the big advantages of tile is extreme durability. 50 year warranties are common, and you shouldn’t be surprised if your slate roof lasts for more than 100 years.
Solar panels can be installed on these roofs without penetrating the tiles with the use of clever brackets that fit underneath the tiles and are fastened to the roof deck.
However, tile roofing material isn’t 100% waterproof. It’s the layer underneath - the underlayment - that provides the final waterproof barrier.
The lifespan will depend on the weight of the underlayment material used. The least expensive type will last 20 to 30 years, but heavy duty materials can last 50. If you’re not sure, have a roofer perform an inspection before you install solar panels.
The most common type of roofing material in use in the United States are asphalt shingles. They vary in expense and quality, and come with warranties as brief as 10 years or as long as 50 years or even lifetime warranties.
3-tab shingles as the least expensive type, and can come with warranties ranging from 10 to 30 years. These are thinner than other types of asphalt shingles, and because of that they don’t stand up as well over time.
Architectural or dimensional asphalt shingles are a thicker product, which makes them more resistant to wind uplift and weathering. You can find warranties as long as 50 years, and CertainTeed even provides a lifetime warranty with their premium asphalt shingles.
Before you install solar panels on your asphalt shingle roof, it’s important to identify the type of shingles you have. Ideally, you have records from your last roofing job that identify the manufacturer and product line of your shingles so that you can look up the warranty information. If you don’t have that handy, contact your roofer.
You want at least 15 years of life in your roof before installing solar
Once you have a better idea of what’s on your roof, you can make a better decision about whether you can install solar panels right away, perform a roof replacement now, or wait a few years before doing a roof replacment and solar installation at the same time.
As a general guide, it would be a good idea to have at least 15 years of life remaining in your roof before installing solar panels. Otherwise, you may need to pay extra for the solar panel removal and reinstallation as part of a future roof repair.
Replace your roof if it has 5 years of life left and you want to go solar
If your roof is nearing the end of its life, the decision is easy. Replace it now if you want to go solar. If you don’t, if your roof ends up leaking just a few years down the line, you’ll have to pay extra for solar work as part of the roof repair.
When you do the roof replacement, look for products with the longest possible warranty - at least a 25 year lifespan, and more if you can afford it. Solar panels come with 25 year power warranties and at least 10 year product warranties, so they will be up on your rooftop for a very long time.
What to do if your roof has between 5 and 15 years of life
If your roofer estimates that your roof is in the middle range of its remaining lifespan - around 5 to 15 years of life left - then your decision is a little tricker. You don’t want to replace your roof too early, otherwise you’ll be throwing away useful life of your roof.
But if you delay going solar, you can also be giving up the energy savings that come with generating your own electricity. So how do you decide?
The best thing you can do is to understand exactly how much money you can save with solar by finding out your payback period. The payback period is simply how many years a solar panel system will take to pay back your initial investment in the system through annual energy savings. Depending on where you live, high electricity prices and local rebates can push your payback period to as little as 5 years.
On the other hand, there are some places in the US where a lack of rebates and low electricity prices can make your solar payback relatively long - 15 years or even longer.
You can estimate your payback period quickly by using The Solar Nerd calculator. Just plug in your zip code and details about your roof, and it’ll show you a graph of how many years it will approximately take for you to break even on your solar investment.
The calculator is a tool for doing a quick estimate on your own. For a more accurate assessment, contact multiple solar installers, who will each give you a system proposal and power generation estimate.
Identify roofing problems on your own
Sometimes you don’t need a professional roofer to tell you that something’s wrong with your roof. Here’s a few roof problems that are easy to identify on your own.
- Missing shingles. This is easy to spot, and a common problem. Severe wind can lift roofing material away, leaving a gap in coverage.
- Damaged shingles or tiles. Curling shingles and cracked roofing tiles are easy to spot from the ground. Asphalt shingles that have lost too much of their granules will start to quickly degrade from UV exposure and start to curl around the edges. If you see this, it’s time for a replacement.
- Lots of shingle granules washing away. If you see a lot of shingle granules washing out of your downspouts or caught in your gutters, that’s a sign that your shingles are nearing the end of their life. Granules will start to separate more easily from the shingle as the asphalt dries out and degrades, so if you see a lot of granules at the base of your downspout, that’s a sign that you need a roofer to take a closer look.
- Damp spots in the attic roof. If you don’t have a cathedral ceiling (one where the underside of the roof is finished), go up to your attic and take a thorough look at the underside of the roof sheathing. If you see any signs of rot or water stains, that’s a sure sign that you have an issue.
If you see any of these issues in your home, call a roofer right away.
Who to call if you need a roof replacement
If you’re thinking of going solar but also need a roof replacement, think about working with a solar company that specializes in both. While many solar companies subcontract their roofing work to other companies, there are roofing companies that have decided to add solar work to their portfolio because a big part of solar installation is ensuring that the roof integrity is properly maintained.
A good roofing company that installs solar will ensure that proper fasteners and waterproofing techniques are used for the installation, as well as doing a proper engineering evaluation of the weight-bearing capacity of the roof.
Finally, by using the same company for both the solar installation and roof repair, you can likely negotiate some cost savings versus using two separate companies. If this is something you need, fill out our form to get solar quotes and mention in the notes section that you also need a roof replacement.
Think about ground mounted solar
One more thing to mention: you can avoid this problem entirely by going with a ground mounted solar installation. While not everybody has a yard that can accommodate the necessary space of a ground mounted array, if you do have the room, you should seriously consider that option. While it usually costs more up front, there are a lot of advantages of putting your solar panels in your yard instead of your roof. Read our article on ground mounted solar to learn more.
The bottom line with solar panels is that it’s more cost effective in the long run if you make an upfront investment in getting a higher quality roof. Standing seam metal roofs are probably the roof to pair with solar. The roofing material is waterproof, so you don’t have to worry about the underlayment like you do with shingles and tiles.
In addition, the standing seam makes installing solar panels a cinch. The solar racking systems for standing seam roofs simply clamp to the seam. This means that there are no roof penetrations that can potentially leak sometime down the time.
Finally, metal roofs last a very long time, even longer than the considerable rated lifetime of solar panels. This means basically not having to worry about incurring the added cost of solar panel removal and reinstall for many decades.