Metal roofing is becoming more and more popular in the residential roofing industry. With the rise in popularity comes the rise in questions that homeowners like you have about metal roof systems.
One of the less common (but just as important) questions is whether or not metal roofing needs roof underlayment. While the answer is simple, there’s a little more to it than just a yes or no.
For over 30 years, the team at Bill Ragan Roofing has helped homeowners understand every material and component that goes into a metal roof system. Because of this, I’ll break down what you need to know about metal roofing underlayment.
This article answers the following questions:
- Does metal roofing need underlayment?
- Is there a right way to install metal roofing underlayment?
- How much does metal roofing underlayment cost?
Disclaimer: When you see metal roof or metal roofing, I’m talking about a standing seam metal roof (the recommended type of residential metal roof).
Does metal roofing need underlayment?
Yes, metal roofing absolutely needs underlayment. Felt and synthetic underlayment are great options for asphalt roof systems.
However, metal roofing needs something different because the expansion and contraction destroys the integrity of the normal types of underlayment. For metal roofing, the underlayment must be high-heat ice and water shield.
(High-heat ice and water shield before metal panel installation)
High heat ice and water shield has cotton-like fibers that won't stick to the metal roof system as it expands and contracts. This protects the underlayment from being destroyed, which allows it to protect your roof decking if water gets underneath the metal panels.
(High-heat ice and water shield before metal panel installation)
While metal roofing needs high heat ice and water shield as underlayment, it’s also commonly installed with premium roof systems like synthetic, slate, and cedar shake. Just know that it will be more expensive than the other types of underlayment.
Is there a right way to install metal roofing underlayment?
Just like metal roofing needs the correct underlayment, it also needs to be installed correctly. The first thing installed for your metal roof system will be lock strips.
These lock strips hold (lock) your metal panels to the edges of your roof (eaves and rakes) to keep them from being ripped or flapping in the wind during strong storms. After the lock strips are installed, the high heat ice and water shield must be installed over the top of the lock strip at the eaves.
If the lock strip is installed over the underlayment, condensation under the ribs will run down the fascia board behind the lock strip. This leaves streaks on the fascia and eventually rots it out.
If left alone long enough, it’ll eventually lead to a leak inside your home. Because of all this, I always recommend hiring a qualified local roofing contractor with experience installing metal roof systems.
How much does metal roofing underlayment cost?
As I said, high-heat ice water shield is more expensive than the other types of roof underlayment. But how much will it actually cost?
Unfortunately, it’s impossible to give you an exact cost number for underlayment and any other type of roofing material. This is due to the prices of roofing materials constantly fluctuating and what your local suppliers charge.
However, I can at least give you an idea of the cost of high-heat ice and water shield for your metal roof system.
High heat ice and water shield can cost around $125.00 per square (100 square feet). While it’s more expensive than other types of underlayment, it’s also the most expensive type of ice and water shield.
For comparison, granular or sand ice and water shield starts at around $50.00 per row of material, while smooth ice and water shield costs around $100.00 per square. Remember, these cost numbers aren’t exact.
However, it does give you an idea of what to expect from a price standpoint for high-heat ice and water shield for your metal roof.
What are the rest of the components that make up a metal roof system?
Now you know that the best underlayment for a metal roof is high-heat ice and water shield. You also learned how to install it properly and an idea of how much it costs.
But your metal roof’s underlayment is just one crucial piece to the puzzle. There are plenty of other important components that make up a metal roof system.
So, there’s still more to know before jumping into your metal roof investment. That’s why I wrote another article breaking down the 7 components and materials of a standing seam metal roof system.
Since 1990, the team at Bill Ragan Roofing has provided high-quality metal roof replacements to homeowners in Nashville and surrounding Middle Tennessee areas. You can count on our metal roofing installation expertise to give you a new metal roof that’ll last for decades.
Check out The Materials Make Up a Standing Seam Metal Roof System to learn the other crucial components of a metal roof.
