Three Types of Underlayment Used With Metal Roofing

Posted by Adam Taylore
2
Sep 8, 2022
190 Views
Getting a metal roof installed means securing your family from different weather conditions for ages. 

There are some conditions to fulfil with the help of a metal roofing Sydney company during installation and one of them is related to the underlayment. 

Different types of underlayment are used by roofers and it is their responsibility to choose the best one. 

Doing this is easy with this post as we discuss different types and offers some ideas related to the selection of the right one.

WHAT IS UNDERLAYMENT? 

An underlayment is a water-resistant material installed under the top roofing layer. Because it is water-resistant, it is a critical part of an entire roofing structure. 

Its job is to protect it during and after the installation process by trapping moisture and repelling water. It's one more role is to provide an extra layer of protection against nature’s elements like snow, rain, ice and fire. 

It also has to protect the roof deck during the installation and because of these crucial roles, choosing the right underlayment becomes crucial. 

Three main types of underlayment used with metal roofing are – 

  • Felt paper underlayment
  • Synthetic underlayment
  • Peel-and-stick (rubberised asphalt) underlayment

Let us look at the details of these types and the first one we review here is – 

FELT PAPER UNDERLAYMENT FOR METAL ROOFING -

This one is also given the name of tar paper and is basically asphalt-soaked felt or asphalt-saturated felt. They are made from the base of natural fibres or cellulose that is treated with waterproofing agents such as asphalt. 

There was a time when it was the most popular for use with metal roofing online, but these days’, contractors as well as homeowners prefer synthetic underlayment.

The reason they cite behind this is that synthetic underlayment is durable and has a longer life.

Pros-

  • Least expensive underlayment
  • Easy to install
  • Readily available and easy to find

SYNTHETIC UNDERLAYMENT FOR METAL ROOFING -

This name has slowly phased out the above-mentioned underlayment because of its features like long-lasting life, durability and better performance in high temperatures and odd weather conditions. 

They are made from polyethylene and polypropylene fibres that are treated with resilient polymers to form a material to be used as a protective barrier between roofing materials. 

They are mechanically attached with roofing caps and staples.

One very interesting feature is that apart from being durable and long-lasting, it also increases the energy-efficiency of metal roofing and here are some pros of using it.

Pros-

  • Longest lasting and far more durable
  • More resistant to tearing, movement and impact damage
  • Easy and fast to install
  • Can withstand direct exposure to UV without drying out

PEEL-AND-STICK SYNTHETIC UNDERLAYMENT 

Another name given to this underlayment for metal roofing online is "ice and water shield" and it is mainly a self-adhesive ring membrane or rubberised asphalt applied between the layers of metal roofing. It is applied directly to the deck and protected by a peel of membrane by the sides. 

It has rubber-like features and also, it is a self-healing underlayment that can seal really well around fasteners and penetrations. 

It is highly effective in reducing the risks associated with water penetration and because of this, it is ideal for areas, where too much of snowfall or rain is experienced.

Pros-

  • Extremely effective for ice dam protection
  • Ideal for a water-tight seal around penetrations
  • Lasts longer and performs better
  • Contributes to a more resilient air barrier




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