Brief Guide on Replacing the Underlayment of a Concrete Tile Roof

Brief Guide on Replacing the Underlayment of a Concrete Tile Roof

Tile roofs are popular all around the world, especially with contemporary houses. They are durable and can easily withstand strong winds and extreme weather conditions. The best thing about tile roofs is that they can be easily repaired without any specialized tools, even if it’s the underlayment.

The underlayment on the tile roofs plays a significant role. They assist roof shingles avoid moisture while keeping the entire roof insulated.

Tile roof underlayment replacement is not as challenging as you may think. That said, several people take assistance from a team of professionals to help them with the job.

Well, without any further ado, let’s take a look at the steps necessary for a quick replacement of the underlayment.

Removing the Old Underlayment

When you are replacing the underlayment of the tile roof the first thing you should be working on is removing the old one that is damaged. You may think the task is easy and won’t take a long time, but it’s a time taking task which can take a few hours at least.

The first thing you need to make sure is using a ladder that can easily handle your weight and long enough to handle you upright. Be careful when you are climbing your roof and walk on it.

Start with the tiles above the row that needs to be removed. You will need a hammer and a pry bar for this. Be careful not to hurt yourself while removing the tiles. Once it’s done, you will then need to remove the plywood underneath and the damaged underlayment. Remove them both carefully so that the areas which are not affected remain intact.

Putting on the new underlayment

After you have successfully removed damaged underlayment and reinstalled the plywood, you can then roll out the felt on the floor. Place the felt on the exposed area of the roof. But before that, make certain the plywood is completely dry. Don’t mount the underlayment on wet wood sheathing as this will keep the moisture from getting dry.

Attaching the underlayment

Fasten the felt on the plywood using the cap nails. Keep in mind to nail it approximately every 20 inches. Make sure you began nailing from the middle of the new roofing felt section. If necessary, place the next layer of felt on the roof floor. Overlap it on the first layer from the sides and thoroughly cover it. Again, fasten the second layer into the roof using cap nails. Continue the same process if you need to cover more area.

Importantly, when you are fastening the underlayment, smooth out all the wrinkles on the felt that will help avoid trapping moisture and cause any problems in the future. 

Trimming the underlayment

Once you have firmly attached the felt on your roof floor, trim the excess felt so there is no overhang. The entire felt layers must cover and fit the floor properly. Even out all the entire area and ensure it does not block the vent of the roof. If it does, it will prevent the air from coming in and going out.

Putting on the new tiles

After you are done with the felt replacement, it’s now time for replacing tile roof. Start your tiles reinstallation from one side and move gradually when one side is completed. Nail your first tile directly to the sheathing and also add mortar underneath your clay tile to provide additional support. Make sure to use medium consistency mortar as they are manageable and easy to apply without any specialized skills.

Place the second tile next to the first one and fix it just like you fix the first one. Continue following the same steps until the entire roof is covered with them once again.

Though tile roofs generally take a bit longer than installing metal panels, they don’t require a lot of tools. However, the process can take anywhere between a few hours, a day, or even a week, depending on big the roof is, and how many people are working on it.


Replacing the underlayment of a concrete tile roof is a time taking process, but it’s not something that can’t be done. You can follow all the steps systematically and replace your roof underlayment alone. It’s just a matter of how much effort and time you are interested to put in.

Nonetheless, if you don’t want to get into all the nuisance, you can hire a team of professionals to perform the job for you. If you hire professionals, it will keep you away from all the hassles of replacing the underlayment all alone. Secondly, you will be confident that you won’t have to get climb up the roof once again and do the job all again alone.

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