Is Sealing Roof Tiles a Good Idea? (Updated for 2022)

Sealing Roof Tiles (Blog Cover)

Sealing roof tiles is rarely worth the investment. However, on the surface, adding a coat of weatherproof sealant to any roofing material sounds like a good idea. After all, you are adding an extra layer of defense to your roofing material and, ultimately, your property.

While there is nothing wrong with the basic concept of sealing roof tiles, there are certain things that you have to think about before you undergo the project. In the following post, Roofer’s Guild will discuss the advantages and disadvantages of sealing roof tiles.

Roofing Tiles and Pitched Roofs

Roofing tiles are only installed on pitched roofs. A pitched roof is simply a roof that has a slope. To be considered a pitched roof, a roof usually has to be sloped at an angle of 20 degrees. 

The slope is important because water can successfully shed off the roof and down into the gutters at this angle with the help of good old gravity. As a result, roofing tiles are not sealed to the roof. They are individual pieces of slate, terra cotta, or concrete laid on top of each other in an overlapping fashion. 

Unlike roofing materials like asphalt shingles, tiles are not fastened to the roof. Instead, the overlapping placement and weight keep them in place and protect the roof’s decking. In addition, though they don’t create a single, continuous layer, the pitch effectively helps them shed water off the roof. 

House With Roof Tiles

Tile roofs differ from asphalt shingle roofs in that they are exclusive to pitched roofs, and the tiles are not fastened to the actual roof system. That distinction is the primary reason why sealing is uncommon.

What’s the Point of Sealing?

Sealing a roof entails adding a waterproof coat to the upper materials. The point of sealing any roofing material is to help keep water from absorbing into it.

Are Roofing Tiles Porous?

Salespeople say that roofing tiles are porous and susceptible to water absorption. And guess what? They’re not lying. Materials like concrete, terra cotta, clay, and slate are indeed porous. However, you must consider that roofing tiles are only installed on sloped roofs. 

So while these materials may be porous, the fact is that they can be. That’s because gravity does the job of shedding water off the roof for them. If roofing tiles were installed on a flat roof (and they would never be, to be clear), it would be a completely different story. 

You would have to seal your tiles every season. The water would pool on the tiles and permeate them constantly. 

But that’s not the case with sloped roofs. In general, roofing tiles on a sloped roof can afford to be porous. As a result, it’s not necessarily detrimental to the structural integrity or weatherproofing of the roof. 

We know what you might be thinking, ‘but roofs with tiles on them still leak sometimes.’ That is exactly right. But that happens for different reasons. Usually, when you get a leak in a tiled roof, it means that one or more of the tiles has been broken. 

One of the downsides of a tiled roof is that the older the tiles get, the brittler they become. So when you need to have some work done on a roof, old tiles can break under the pressure of a footfall. 

Slate Roof Tiles

Another reason tiled roofs leak is from a bad installation. To provide full coverage, the tiles must be carefully overlapped. Ridge caps also need to be installed carefully to protect the vulnerable point of the roof where the two slopes meet at the apex. 

Benefits of Sealing Roof Tiles

Yes, there definitely are some benefits to sealing your roof tiles. Take a look at the most important ones:

  • It May Prevent Cracking: If you live in a colder climate where rainwater can freeze on the roof, sealing may prevent tiles from breaking. When water enters hairline cracks in your roof tiles and freezes, the expansion can break the entire tile. Keeping the water out with a sealant may prevent this. 
  • It May Extend the Life of your Tiles: An extra layer of water protection may help slow down the weathering of your tiles, potentially extending the life of the material by just a few years. 

Drawbacks of Sealing Roof Tiles

Before you go out and buy sealant or call up your local roofing contractor, take a look at some of the disadvantages of sealing roof tiles:

  • You Need to Pressure Wash the Tiles: Before you can apply a sealant, the tiles need to be as clean as possible. Most contractors will use a pressure washer that can strip the tiles’ surface material if not carefully done. Of course, to pressure wash, you will need to get up on the roof. Any time you step on roof tiles, you risk breaking them, which, as discussed, is one of their inherent disadvantages. 
  • It Could Ravage the Good Looks of the Tile: Sealant isn’t permanent. After just about a season, it will strip off, and the color of your roofing tiles goes with it. When a sealant wears and chips away with the rainwater and UV exposure, it can alter the appearance of your roofing tiles – rarely for the better. 
  • It May Not Be Worth the Effort: If you live in a stormy area, you may have to reapply sealant every couple of years. This can add up to a lot of money and effort that may not even be necessary. Plus, if you plan to do the work yourself, it can be hazardous to get up on the roof, pressure wash, and apply the sealant. 

Final Thoughts on Sealing a Tile Roof

In most cases, sealing a tile roof is not worth the investment. Instead, you should have your roof inspected by a professional once a year to ensure you don’t have any tiles that need to be replaced. In most cases, roofing tiles will provide enough weatherproofing on their own. 

However, if you live in a frigid region of the country, you may want to consider sealing roof tiles to prevent freezing and breaking.