Like floors, roofs can be slippery when wet
Rain can make your roof deck slippery, making it dangerous for DIYers and professionals to work in the rain.
Moisture trapped under your shingles can lead to mold growth and poor fastener connections.
Some shingle manufacturers may actually void your roof warranty if you install the materials in the rain.
If you’re installing a new roof and the weather isn’t cooperating, you might wonder if it’s safe to install shingles in the rain. While light rain might be safe for professionals to work in, most of the time, you’ll want your roofing materials to be completely dry when you install them. In this guide, we’ll explain why you shouldn’t install shingles in the rain and what to do if the weather surprises you mid-project.
Generally speaking, no, you shouldn’t install shingles in the rain. Not only is it unsafe to work on a slippery roof deck, but rain and moisture can actually affect the installation itself, leading to a less stable roof, warping of the roof deck, and even mold and mildew becoming a problem under your shingles. If you’re DIYing roof repair or replacement, always check the weather beforehand and plan around precipitation.
Most local roofing companies also won’t install shingles in the rain—which should serve as a warning for any DIYers considering it.
Roofing contractors might be willing to work in light rain if they believe it’s safe, but they’ll likely delay the installation if they expect moderate to heavy rain. They may wait a day or two after heavy precipitation to allow your roof deck to dry out, too. If you’re in a rush to avoid ongoing water damage from a leaking roof, hire a roofing contractor who is willing to work in less-than-ideal working conditions to get the job done as quickly as possible.
There are a few reasons you should avoid installing shingles in the rain, including safety issues and problems with the installation itself.
Most importantly, rain can make your roof deck slippery, which makes working on the roof far more dangerous. Professionals with proper roofing harnesses and experience might be willing to work in light rain, but you should never get up on your roof if it’s actively raining or if the roof deck is wet.
If you’re installing solar roof shingles, it can also be dangerous to make the necessary electrical connections in wet conditions.
Rain can warp and distort your roof decking because the wood will absorb moisture. Installing shingles over a wet roof deck will hold that moisture in and make the problem worse. You could end up with a wavy or uneven roof if you move forward with the installation while it’s raining.
Depending on how long the installation takes and how heavy the rain is, you could also run into problems with water seeping through the roof deck and causing water damage in your home.
Installing roof shingles over a wet roof deck will trap the moisture between the building materials and can lead to mold and mildew. The space will eventually dry out, but likely not before you do some damage to the decking material.
Your roof deck will expand slightly when it’s exposed to moisture, and driving roofing nails into a wet deck won’t cause any problems right away. However, when the wood sheds the moisture and shrinks, the movement can compromise the connection with the fastener, leading to a less secure roof.
Finally, some roof shingle manufacturers will void your warranty if you or a professional install the shingles in the rain. This depends on the company and the product line, but even if your specific warranty doesn’t mention anything about installation conditions, the fact that some do mention it should be enough to lead you or your professional to wait out the rain.
Sometimes, you plan around the weather the best you can but still get hit with rainfall while your installation is underway. If it does start raining, it’s a good idea to set up some tarps to keep the exposed roof decking dry while you wait for the rain to pass.
Alternatively, you can work in sections if you’re doing the job yourself. Tear off a section of old roof material and put down the underlayment right away. Install new shingles over that section before moving on to the next one. This can take some additional roof measuring to coordinate, but it will help minimize the amount of roof deck that sees direct rainfall.
As the first layer of water protection for your roof deck and the building materials below, underlayment is designed to prevent water damage, so it’s okay if it gets wet. However, you shouldn’t rely solely on underlayment for protection. If rain interrupts your roof project and you have all of the underlayment down, you’ll likely be fine, but you should install shingles over that layer as soon as possible, as long-term exposure can lead to water damage.
You should plan on waiting as long as it takes for the roof deck to dry out completely if it gets wet. In most cases, this will take about 24 hours, but it could take longer if you have shading on your roof or cloudy weather after the rainfall that prevents the sun from drying the material.
