Are you overwhelmed by all the different metal roofing terms (nail strip, snap lock, mechanical seam) and unsure which one’s actually right for you? Are you frustrated by how hard it is to understand which one will prevent leaks and best protect your Seattle home?
At RoofSmart, we understand that choosing a roof can be overwhelming and difficult. That’s why we recommend roofing options to each individual customer based on their needs, preferences, and budget. We help hundreds of customers each year weigh their options and find the best roof for their home.
In this article, we’ll walk you through the three main types of standing seam metal roof panels—nail strip, snap lock, and mechanically seamed—and break down how they differ in cost, performance, installation, and weather resistance.
You’ll leave this article knowing exactly which panel is best for your specific roof type, budget, and long-term goals.
What are the different types of standing seam panels?
Standing seam panels are fastened and sealed in a variety of ways. To help you understand which panel type is best for your roof’s needs, here is an overview of the 3 different types of standing seam panels.
1. Nail Strip Panels
Image from Western States Metal Roofing
Nail strip panels are fastened into place using nails. The panel has designated slots where you screw the nails in place and then the next panel snaps in place over it to cover the nails.
Pros:
- Most affordable
- Easiest and quickest to install
- The screws are concealed, making the roof watertight
Cons:
- The screws cannot be too tight or too loose
- The metal can rip if the screw is too tight
- This panel is most likely to fail out of all 3 options
- Oil canning is more likely
- Limited to 30-foot strips because the panel expands and contracts
2. Snap Lock Panels
This type of panel snaps together like the nail strip does. However, the key difference is that the panels are fastened together with clips instead of using the nail strip.
In the image above, you can see the clips securing the panel in place along the edge. These are used instead of screws to hold the panel in place (notice how there are no slots for the screws).
Snap lock standing seam panels are the most common metal roof choice for Seattle homeowners because they offer the best balance of cost and protection.
Pros:
- Use of clips makes the panels more secure and durable
- Can be used on steep, regular, and some low-slope roofs
- Great waterproofing because the clips are concealed by the panels
- Quicker and easier installation than a mechanically seamed roof
Cons:
- More expensive than nail strip panels
- Only a roofer with experience can install it correctly
3. Mechanically Seamed Panels
Mechanically seamed panels have the best waterproofing out of all the options because they are sealed together using a special machine.
Basically, you run the machine over it, and it folds the metal together. Butyl is injected at the seam of the panel before it's mechanically seamed to add extra protection.
You can do a single fold or a double fold.
- Single lock: This is best if your Seattle home has a low slope and a metal roof, but you want to make sure that it’s protected from standing water. Mechanical seaming strengthens the seam between the panels so that no leaks can happen.
- Double lock: For most Seattle area homeowners, this is probably not necessary. Double lock seams are the highest level of waterproofing that you can get on a metal roof, but they are really only needed in extreme weather conditions with snow. If you live in Snowqualmie Pass, double lock panels might be useful, but we don’t get enough snow around Seattle to warrant it.
Here's the difference in how single lock and double lock seams are folded:
Image from Sheffield Metals
Here are the benefits and drawbacks of mechanically seamed panels:
Pros:
- Best waterproof metal roof
- Good for extreme weather conditions (like snow)
- Great for installing metal on extremely low-slope roofs
Cons:
- Most expensive and labor-intensive to install (especially with double lock)
- Not really needed in Seattle (unless you have a low-slope roof)
How do I know which type of standing seam panel is right for my Seattle roof?
With so many options and factors to consider, it can be difficult to make your decision. Make sure to consider which panel best fits your needs and budget.
Standing seam metal roofs are expensive, but they offer you great value by being strong, durable, and lasting for 50+ years.
Nail strip panels are best for you if you want to cut down on costs as much as possible, or you want a quick installation.
Snap lock panels are a great option if you want a panel that will stay secure and avoid damage even while the metal expands and contracts. This is a good middle ground for getting great protection from your metal roof without the extra cost of mechanical seaming.
We recommend snap lock style panels for most Seattle homeowners for their durability and leak resistance.
If you have a low-slope roof, mechanically seamed panels are a great option for you. However, if you live in the Seattle area and have a regular roof slope, you probably don’t need mechanical seaming. A regular snap lock roof should be enough protection against leaks and water damage.
How Much Will a Standing Seam Metal Roof Cost You in Seattle?
Now that you understand the pros and cons of nail strip, snap lock, and mechanically seamed panels, you’re better equipped to choose the right standing seam metal roof for your Seattle home. Whether you're prioritizing cost, durability, or waterproofing, there’s an option that fits your specific needs.
But we know that understanding the types of panels is just one part of your decision. The next big question is: How much is this actually going to cost?
Your next step is to read “How Much Does It Cost to Install a Metal Roof in the Greater Seattle Area?”. This article will give you clear pricing ranges, explain what impacts the total cost, and help you budget realistically so that you can move forward with confidence.
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