A Comprehensive Guide to Tiled Roof Underlayment

The roof of a house takes a beating by regularly standing up to extreme weather conditions and other environmental elements to protect the property and the people and belongings inside. 

Exposure to the scorching sun, hail storms, heavy rain or snow, and strong winds can create wear and tear on the roof. If the roof wear and tear is not addressed for long, it can create issues with mould, moisture, mildew, and leaks, and you might require professional tiled roof restoration

The roof’s exterior, i.e., roofing tiles everyone sees, is the first defence against external elements. But the layer that no one sees, i.e., the tiled roof underlayment, is equally vital to protect the home from damage. 

Underlayment is installed between the roof attic and the roof tiles to provide support and protection to the roof.

Read further to learn everything about tiled roof underlayment.

What is Tile Roof Underlayment? 

Tile roof underlayment is the layer of protection installed between the actual roof and the exterior layer of roofing tiles. 

Its primary function is to provide support to the roofing tiles. Moreover, roof underlayment creates a water-resistant barrier to protect the roof if roofing tiles are broken or cracked, leading to water leaks. 

Types of Roofing Underlayment

Tile roof underlayment comes in the following different types:

Asphalt felt underlayment

To manufacture an asphalt felt underlayment, the manufacturer soaks a base material to create a water-shedding barrier between the roofing tiles and the roof deck.

The underlayment installed by a roofing specialist Melbourne can help homeowners improve the durability of their roofs. In addition, asphalt-felt underlayment is relatively less expensive than synthetic one. 

You can find asphalt felt underlayment in two different weights – 30 feet and 15 feet, with the former being more heavy-duty and sturdier enough to withstand the external elements to which a roof is exposed. 

Now that 30 felt underlayment is heavier than 15 feet, it can be difficult for a non-professional to get it onto the roof and work with it. So, it’s advisable to work with a professional roofer. 

Rubberized roofing underlayment

Like the bicycle tire tube, rubberized underlayment is elastic and water-resistant. Also known as rubberized asphalt, its flexibility allows the underlayment to perform well in all climates, ranging from hot summers to frigid winters.

Synthetic underlayment

Synthetic underlayment is another type of roof tile underlayment made from durable polymers and offers several advantages compared to asphalt felt underlayment. It is lighter and stronger than asphalt-felt underlayment, making it better able to withstand the impacts of debris and hails. 

In addition, the underlayment provides resistance against moisture and fungal growth. Now that it’s a durable underlayment, professionals find it easier to install without causing severe damage that could allow water to reach roof decks. 

Importance of Roof Tile Underlayment

Not every roofing tile is durable and sturdy enough to cover and protect the whole roofing structure. 

Without roof-tile underlayment, you won’t be able to preserve some corners and edges of your roofing structure from damaging impacts of weather and external elements. The overlapped roofing shingles can make sealing all the roof’s corners impossible. 

So, here are some advantages of roof tile underlayment:

  • Roof tile underlayment can readily provide water resistance or waterproofing required for roofing tile surfaces while covering specific areas of the roof. Therefore, roof underlayment is a critical part of tiled roof restoration
  • All types of underlayment, as discussed above, are manufactured from materials that add an extra layer of protection to the roof. These materials form a barrier to prevent moisture or any external element from penetrating and damaging the roof surface.
  • In addition, underlayment can seal edges, roof protrusions, and valleys that bare roofing tile surfaces can’t usually cover. 

How Long Can Tile Roof Underlayment Last?

A tile roof underlayment installed by a roofing specialist in Melbourne can last years. 

Traditional asphalt felt paper underlayment can last approximately 20 years, and the synthetic options can last even longer. 

Since synthetic roof tile underlayment has the best tear and resistance ratings, it can withstand plenty of weather conditions and heavy roofing tiles. Moreover, you can ask the manufacturer for a warranty to give you peace of mind. 

Does a Leaky Roof Need New Roof Tile Underlayment?

If your roof structure leaks, the underlayment might be compromised in at least one spot. In such a case, you should contact a tiled roof restoration professional. 

He will inspect your roof to identify the root cause of the leaky roof and the extent of damage to the underlayment. In case of severe damage to the underlayment, the roofing expert might suggest replacing it with a new one. 

Factors to Consider for Choosing Roof Tile Underlayment

 If considering installing a new roof tile underlayment, consider the below-listed factors to choose the proper underlayment:

Weather conditions and climate 

If you reside in an area with relatively mild or moderate weather, you should opt for asphalt felt underlayment to provide support and protection to the roof. Synthetic roof tile underlayment is ideal for homes in areas with extreme weather conditions like storms, hail events, heavy snowfall, etc.

Roof slope

A professional roofer might provide specific recommendations for installing underlayment and the optimal amount of overlap depending on the roof slope.


Budget is one of the most essential considerations during a roof project. Asphalt-felt underlayment is less expensive than synthetic one. However, the former underlayment doesn’t provide as much protection as the latter. 

From a budgetary perspective, it’s rational to go for the product that has a higher upfront cost but provides superior protection while requiring fewer costly repairs over the years.

To wrap up it all

With this article, it can be safely said that roof tile underlayment is a necessary feature that your roof structure must have. Although no one can see the underlayment, it is the second layer of defence, providing a barrier against moisture and protecting the roof, deck, and home from costly damage. 

Furthermore, you should assign the roof tile underlayment project to the roofing specialist Melbourne for optimal installation and, thus, availing of the maximum benefits of underlayment. 


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