Once you decide you want a metal roof, you’ll find yourself having to decide which metal roof system is right for your situation. This is where the standing seam vs screw down panel argument comes into play.
We here at Bill Ragan Roofing want you to have the information you need to make the right purchasing decision. That's why we're going to break down the two types of metal roof systems and let you decide which one is right for you.
By the end of this article, you'll be able to make this decision all on your own.
What are the two types of metal roof systems?
The two metal roof systems to choose from are a standing seam or a screw down panel. Both systems have their place in the industry and both have their advantages and disadvantages.
What is a standing seam metal roof system?
A standing seam metal roof system is a series of panels that are locked together at the seams or seamed mechanically. The ribs (standing seams) are usually between 12 and 24 inches apart depending on the length of the panel and aesthetics of the structure.
What is a screw down metal roof system?
A screw down panel is just what it's called; it's screwed down. The panels are fastened down using screws and washers screwed through the face of the metal.
Standing Seam Metal Roof vs. Screw Down Metal Roof
If you’re getting a new metal roof installed over a heated space then you’re probably going with a standing seam metal roof. Even though it’s usually installed as a new roof, customers also like to use a standing seam for accent purposes because of the clean look it has. It’s popularly used for front porches, side porches, back porches and bay windows.
Screw down metal roofs are usually used over a carport, garage, back screened-in porch, barn, anywhere that’s not a living or workspace. However, you can find contractors that will install them over old roofs.
Whatever metal roof system you choose, you need to be aware of factors like expansion capability, maintenance, oil canning, and cost so you can make the most informed decision possible.
Which metal roof has better expansion capabilities?
The metal for your new roof will go through something called thermal expansion. Thermal expansion occurs when a material (metal) expands when heated and then contracts when it cools down. The expansion capability of the two systems determines which is better for your specific situation.
Standing seam panels are fastened under each rib. The fasteners under the ribs allow the roof to expand and contract freely as the clips stay fastened and the panels glide back and forth. Unlike screw down panels, this allows the panels to expand and contract freely.
A screw down metal roof system is installed by securing the panels down by screwing through the metal. The problem is, this method of screwing the metal down, doesn’t allow the metal to expand and contract naturally. Due to the lack of being able to expand and contract, the screws will eventually wallow out the holes they are screwed into. This means that you will periodically have to replace the screws with the next size up.
Due to a lack of expansion capabilities on a screw down panel roof system, I do not recommend that you use this type of roof system over any heated living or workspace. Beware, there are many contractors that will install this type of roof system without telling you about how expensive it is to maintain.
Which metal roof requires less maintenance?
Once a standing seam roof has been installed, virtually no maintenance is required except at the penetrations such as vent pipes, gas pipes, etc. The boots and collars on these pipes will never outlast any roof system. Cleaning is the only other general maintenance that’s needed and that’s a personal choice for each customer.
As long as it’s installed properly, a standing seam metal roof shouldn’t have problems and need very little maintenance.
Unlike a standing seam, the fasteners on a screw down panel are exposed. As time passes, the pressure caused by a lack of expansion and contraction of the metal will cause the holes in the washers to get wallowed out by the screws. This leads to leaks and the need for regular maintenance.
A contractor will have to come out every 5-10 years or so to replace every one of the screws before it causes bigger problems or before a strong storm tears the roof off. The problem with this is that you won’t know it’s time to do this maintenance until it’s too late. It typically shows up as leaks in your interior.
Which metal roof will oil can?
While a screw down metal roof has so many ribs in it that it’s impossible to oil can, it’s very common in standing seam metal roofs.
Some installers will put the standing seam panels too tightly together and then put the clips on them. It has room to expand longways but the problem is that there's no room for it to expand sideways. That starts the oil canning process.
Oil canning is when the metal on your roof is trying to expand but it's in a bind. This starts the metal to form large bubbles. These bubbles then turn into what is commonly called bubbling which turns into oil canning. It’s called this because it will look a lot like a bunch of oil cans lined up together. It doesn’t cause any functionality problems, but it is an aesthetic issue.
If curb appeal and aesthetics are a big deal to you just be aware that oil canning is a potential problem in a standing seam roof.
As I’ve said before, I wouldn’t recommend using a screw down panel over any heated space. Does a standing seam cost a little more? Yes, upfront you're going to pay triple. What you need to ask yourself is if almost zero maintenance and peace of mind for the next 50 years is worth the extra money.
Whatever your budget, the contractor you hire should work with you and your finances to give you the best roof that will last you years to come.
The best metal roofing system for you
The standing seam metal roof is likely to cost twice as much if not more than the cost of a screw down metal roof. But the long-term maintenance cost of the screw down panel should offset that up-front cost of the standing seam, which once installed, you can forget about it.
Remember, I do not recommend that you use a screw down metal roof over any heated living or workspace because of its lack of expansion capabilities.
How long will your new metal roof actually last?
Now you know how the two types of metal roofs compare to each other on key factors. This helps you decide which one is right for your situation.
But there's still one more factor we didn't discuss, a metal roof's lifespan. Because lifespan is the return you get out of your metal roof investment, we wrote another article breaking it down for you.
Since 1990, the team at Bill Ragan Roofing has been installing residential metal roof systems for homeowners in the Nashville are.Whether it’s installing your new roof, regular maintenance, or roof repairs you can count on us to do the job right.