Whenever you’re doing an outdoor project, especially construction projects, tracking weather is a part of the job. For example, if you’re building a brick wall, you need clear days for the mortar to dry. When the mortar is wet or over-saturated with water, it can run and smear all over your bricks when it rains. But what about tar paper? Can tar paper get wet?

Tar paper is the compact layer that sits between your home or building’s plywood and the shingles of your roof. It almost feels like wool and provides the buffer and support your shingles need to stay in place for years. Despite its thickness and texture, tar paper, also referred to as roofing felt, repels water instead of absorbing it. 

For the most part, tar paper can get wet, but only to a certain extent. Too much water will damage it and impair its ability to keep your roof’s integrity. If left wet for too long, the fibers in the tar paper will start to break down and fray. It can lead to holes and leaks in your roof layers that will be more trouble than you want. 

Just how wet can you let your tar paper get? What do you do if it gets wet before you can put your shingles on? Let’s explore what you can do and how to keep your tar paper and the rest of your roof in great shape. 

Keeping Your Tar Paper Dry

Roof installation or roof replacement usually isn’t a one-day job. If there are enough people, then sure you can finish it in a single day. However, most roof projects take a least a few days. That means leaving your roof exposed to the elements before it is complete. 

This is fine in drier climates or in areas with little rain. Even in wetter areas, crews can check the weather before the work starts to better guarantee they don’t encounter any rain. 

We’ve already mentioned that tar paper, also known as roofing felt, can get a bit wet, and it’s not too big of a deal. A sprinkle or a drizzle here and there won’t impact its performance. However, heavy rains or prolonged rain can damage the tar paper and other parts of your roof. If you try to put shingles on wet tar paper, for example, it can be harder to make precise lines, and you could come across mold growth resulting from water trapped inside. 

One of the most significant issues is that roofing felt wrinkles and contracts when it gets wet. Any water it absorbs affects its shape. When it dries out, it relaxes and expands. This is no big deal when if there are no shingles installed, but it can shake shingles loose and leave holes in your roof if you install shingles on wet roofing felt. 

How to Make Sure Your Tar Paper Is Dry

Whether you’re paying someone to install your roof or doing it yourself, you should always make sure your tar paper is dry before you move forward. Here are some ways you can do it. 

  1. Check the forecast – Look at the weather before you begin. Map out approximately how many days it can take you to complete the roof installation and work in a good-weather window where there is less chance of rain. 
  2. Let it dry first – If it does rain, then give it at least 24 hours of direct sunlight exposure before shingle installation. If it’s cloudy or generally damp, then give the tar paper longer to dry. There should be no trace of moisture when you’re putting your shingles on. It could take a few days to dry completely. 
  3. Check for damage – Before you begin with shingle installation, go over your tar paper to check to make sure it’s still in good condition. You don’t want any wrinkles or overly-frayed sections that will impair your roof performance. 
  4. Buy a tarp cover – You can buy a tarp cover for your roof or book an appointment with a company that specializes in installing large tarp covers on roofs during work breaks. This is a good preventive measure when the forecast calls for rain suddenly or you don’t have time to complete the roof before it rains. 

These are just a few things you can do to avoid dealing with wet tar paper. Before you start your roofing project, do some research and have a plan in place in case bad weather comes along. 

Reasons Not to Install Shingles on Wet Tar Paper

There are several reasons why you should never install shingles on wet tar paper. Here are a few of them.

  • Manufacturer Warranty – Putting shingles on wet tar paper could void your manufacturer’s warranty. Most roofing supply companies are very explicit about their products’ design and purpose. If you look, most will have strict guidelines about how to use them regarding moisture, rain, and other water issues. If you disregard warnings and instructions, it could void your manufacturer’s warranty even if something legitimate is wrong with your products. It’s better to avoid the chances of that happening. 
  • Damage Outside of Repair Warranty Window – Sometimes, it takes time to spot problems related to moisture under your shingles. When you trap water inside your roof, it naturally takes more time to dry. The drying process could take weeks or even months. When the tar paper finally dries and expands back to its original size, you will start to see crooked shingles or bubbles in your roof. However, if it takes too long, it could fall outside of your repair or construction warranty.
  • Roofing Performance Impact – You should wait for tar paper to dry because wet tar paper adversely impacts your roofing performance. Everything on your roof should fit together like a puzzle. All of the pieces should be together snugly to avoid rain, wind, and other weather damage. It also helps regulate temperatures indoors by providing the insulation you expect—loose shingles due to wet tar paper harm your roof’s ability to perform. 

The Benefits of Roofing Felt

Tar paper, when dry, services an important role in keeping your roof in good condition for longer. Roofs represent a significant investment for most homeowners, so you’ll want to keep it around for as long as possible. A good roof can last for decades now. Unfortunately, skipping steps and installing shingles on wet tar paper could cost you thousands of dollars in repairs and a big headache.

But what is tar paper for, anyway? If you live in a rainy area of the country, can you just skip it altogether? 

Tar paper serves a purpose. For instance, people in cold weather who experience frequent snow and ice need roofing felt to act as an insulated barrier between outdoor weather conditions and a warm home inside. 

If a house doesn’t have tar paper, the artificial heating from indoors will creep up through the roof and melt the snow. When the snow melts too quickly, it increases the chances of a roof leak and water in the house. Tar paper slows the process and makes it easier for the snow to melt naturally and find its way into the gutter system. 

Roofing felt also acts as another layer of protection on your roof. If something like a limb or a bird gets through a shingle, they still have to get through the tar paper before reaching your plywood roof. Likewise, if bad weather or age shakes a shingle free, your roof isn’t exposed. 

Finally, tar paper can help with sound reduction to lower noise pollution when it rains or from cars out on the street. 

How to Keep Things Dry

We’ve already mentioned a few tips on what to do if your tar paper gets wet. Of course, checking the weather is one of the best things to avoid a catastrophe, but there are other vital points to follow to keep your roof dry. 

  • Hire the Right Contractor – If you’re not replacing the roof yourself, choosing the right contractor is probably the most critical decision. The company you decide to use impacts your final price, how responsive service will be, build quality, etc. Read reviews online and get multiple bids to help you make the right choice. 
  • Use Enough People – Whether it’s you or the company you hire, get enough help so you can finish your roofing project in as little time as possible. Shortening your schedule lowers the risk of weather exposure. 
  • Buy Enough Tar Paper – One mistake people make is not buying enough tar paper. They come up short and then run to the store only to find that what they need is sold out. Measure your roof and buy a bit extra to accommodate for any mistakes. 

Keeping your tar paper dry is a terrific way to ensure the best possible long-term roofing performance.