What’s The Best Underlayment For Metal Roofs?

Any roof is made up of several parts. One of the most essential parts is the underlayment, which sits under the outer layer of your roof. If you’re considering installing a metal roof, there are several different types of underlayment that you can consider. Which one will be right for you?

What is Underlayment For Metal Roofs?

To understand which underlayment is right for you, you’ll first need to know what exactly it does. This material is attached to your roof deck, to act as a barrier between your deck and the other roofing materials. Typically, it should act as a vapor barrier or moisture barrier, to help keep water out of your roof where it could cause damage. 

When it comes to metal roofs, it’s essential that you have underlayment installed. Not only do you need it for the above reasons, but you need it for noise reduction too. Without that layer, rainy days are going to be noisy in your home as the raindrops fall on your metal roof. 

Which Underlayment Should You Choose?

There are several different types of underlayment available, so any one of these will be right for you. Here are the options that are available to be fitted under your metal roof:

Felt underlayment: You may also see this referred to as asphalt felt/tar underlayment, but these refer to the same material. It’s a very common option that’s most often used on steep sloped roofs. Its biggest benefit is that it’s cost-effective. When you’re installing a metal roof you will be paying more for it, so this will be a big benefit for you.

As a material, it’s also water resistant, so it will work to stop water from entering your roof and causing more problems. Also, it’s widely available so it shouldn’t be a problem for your roofer to install it.

It’s worth noting that this underlayment doesn’t have as long a lifespan as others on this list. As a metal roof can last for decades, that’s something that you need to keep in mind. Plus, if you live in an area that gets high temperatures, it won’t last as long. As well as this, the underlayment isn’t easily recycled at the end of its lifespan, like your metal roof is. 

Synthetic sheet underlayment: This is a newer type of underlayment that’s made by weaving together either polyethylene or polypropylene with a polymer, to create that barrier material. As an underlayment, it’s a good material as it has a longer lifespan than felt underlayment, and can handle those higher temperatures if needs be. Plus, it’s much more durable thanks to the polymers involved with its construction. 

You will need to remember that this material will be more expensive than felt underlayment. It also has a low permeability rating. That makes it great at keeping moisture out of your roof, but will also make it harder to ventilate it. 

Self-adhering membrane underlayment: This type of underlayment is made from either rubberized asphalt or butyl-based adhesive with a polyethylene carrier sheet. This membrane uses a peel-and-stick formula that allows it to be stuck down onto your roof deck. 

These offer some good benefits to homeowners. As the membrane is fully stuck down onto the roof deck, it’s a great air barrier. It can also offer protection in high temperatures, which is good for those living in hot climates. Conversely, if you live in a colder climate you’ll get good ice dam protection with this material. 

You will need to make sure that you pick a good quality membrane, as lower quality ones run the risk of peeling away from the roof deck. That leaves your deck exposed to the elements, so consult your roofer about the membrane you should get. It’s also worth being aware that your insurance company may offer a discount for properly installed membranes. Make sure you ask your insurance company, as that could help lower the cost of your new roof. 

Which Underlayment is Best For Your Metal Roof?

Now that you’ve seen the options that are available to you, which underlayment is going to be best for your metal roof? The fact is that there’s no one clear outlier when it comes to quality. As such, it’s always a good idea to talk to your roofer. They’ll be able to give an expert opinion that’s based on their knowledge of underlayment, as well as your roof and your climate. 

For example, if you live in a hotter climate they recommend synthetic sheet underlayment or self-adhesive membrane, as they’re able to cope better in warmer temperatures. If your insurance company offers a discount for self-adhesive membranes, then they may recommend this type of underlayment. Make sure you talk to your roofer about what’s right for your home. 

Other Metal Roofing Barriers

You’ll also want to consider other barriers to have installed under your metal roof. If you live in a cold climate, for example, an ice and water shield will be needed. These barriers are made either of rubberized asphalt or butyl-based adhesive sheets. Typically, they’ll come in a peel-and-stick format. These are used as well as typical roof underlayment to protect your roof. 

If you need extra protection against condensation, then you have the option of using a vapor barrier too. These will help reduce the amount of condensation that accumulates in your roof. These are often recommended to be installed under metal roofs, to help protect your home and give your roof a longer lifespan.

Again, you can talk to your roofer about what’s needed on your roof, and make a plan for what they will install for you. 

Now you have all the details on metal roofs and the underlayment that you can choose from. You will need underlayment to protect from the elements and reduce the amount of noise from your roof. Your roofer will help you pick the one that suits your home best. 

And if you live in Virginia areas such as Warren, Middleburg, Winchester, or Leesburg, we’ll be happy to help you with your gutter and roofing needs.