Deck Crimping Tool: How to Lock Steel Deck Side Laps Fast (Rent or Buy)

A deck crimping tool is one of the most underrated pieces of equipment on a steel decking job. It mechanically fastens the overlapping side laps of adjacent metal deck sheets by crimping (or “button punching”) the interlocking edges together, giving you a clean, code-recognized side lap connection without dragging out a welder or burning through boxes of screws. At Keystar Industries in Eagan, MN, we supply USA-made steel deck every day, and we field this exact question from contractors all the time: what fastens the seam between the supports? The answer, most of the time, is a deck crimping tool.

In this guide, we’ll walk through how the tool works, the different types you’ll run into, how crimping stacks up against screws and welds, and when it makes sense to rent versus buy. We’ve been around metal deck long enough to know the difference between theory and what actually holds up on a deck, so we’ll keep it practical.

What a Deck Crimping Tool Actually Does

When you lay metal deck, each sheet overlaps the next along its long edge. That overlap is the side lap, and it has to be fastened so the panels act together as a single, rigid surface. A deck crimping tool deforms the male and female side-lap profile so the two edges fold and lock into each other. People call this a button punch, because the finished connection looks like a small raised button or dimple pressed through both layers of steel.

That locked seam is the whole point. Without a fastened side lap, two adjacent sheets are just sitting next to each other and can shift independently under load. Once you crimp or button punch them, they move as one. This is what lets the deck transfer in-plane forces and develop diaphragm strength, which matters a lot for resisting wind and seismic loads.

Here’s the key distinction we explain to crews almost daily: support fastening and side-lap fastening are two different jobs. Fastening the deck down to the steel frame (the joists, beams, or bar joists) is handled with welds, screws, or power-actuated fasteners. A deck crimping tool handles the seam between those supports. You need both.

Why Side Lap Fastening Matters

The Steel Deck Institute (SDI) and your project drawings call out side lap fastener spacing for a reason. Those connections aren’t decorative. They stitch the panels together so the floor or roof can act as a structural diaphragm.

Skip them or space them wrong, and you compromise the deck’s ability to carry lateral loads back to the building’s frame. The engineer of record specifies the spacing based on the diaphragm design, so the intervals on your drawings are not suggestions.

A few quick reasons the side lap connection earns its keep:

Diaphragm action. Stitched panels share load and resist racking, which is critical in wind and seismic zones.
Fastened seams reduce deflection and keep the deck surface tight and flat.
Code compliance. Inspectors check for specified side-lap fasteners at the required intervals.
Concrete performance. On composite and form deck, a tight side lap helps control slurry leakage when concrete goes down.

For more on the engineering side of all this, the Steel Deck Institute and the American Iron and Steel Institute are the authoritative references the industry leans on.

Types of Deck Crimping Tools

Not every job calls for the same tool. The right metal deck crimper depends on the deck gauge, the volume of seam you’re fastening, and how much you want to spend up front. Here are the main categories.

Manual Hand Crimpers

These are the lever or plier-style tools a worker operates by hand, one crimp at a time. They’re light, simple, and need no power source. For smaller jobs, punch lists, or tight spots a powered unit can’t reach, a manual deck seaming tool is hard to beat. The trade-off is labor: high-volume seams will wear out a crew’s hands.

Button Punch Tools

A button punch tool is the classic side-lap crimper. It presses a clean, locking button through the overlapped edges. “Button punch deck” is shorthand a lot of crews use for deck that’s been seamed this way. These tools are reliable, repeatable, and the workhorse of side-lap fastening on form and roof deck.

Powered Crimpers

For large floor plates and high-volume work, a powered crimper takes the fatigue out of the equation and keeps the connection consistent crimp after crimp. They cost more and add weight, but on a big job the speed pays for itself fast. This is the category where renting often makes the most sense, which we’ll get to below.

Crimping vs. Screws vs. Welds for Side Laps

Contractors ask us all the time which side-lap method is “best.” Honestly, it depends on the job, the spec, and what’s in your truck. Here’s an honest side-by-side to help you decide.

Factor	Deck Crimping / Button Punch	Self-Drilling Screws	Welds
Power needed	None (manual) or portable	Drill / driver	Welder + power
Speed on long seams	Fast, especially powered	Moderate	Slower, more setup
Consumables	None	Screws	Rod, gas, PPE
Skill / certification	Low	Low	Welder cert often required
Consistency	Very consistent	Consistent	Operator-dependent
Weather sensitivity	Low	Low	Higher (wind, moisture)
Best for	Form, roof, composite side laps	Side laps where screws are specified	Where welded seams are specified

The takeaway: a deck crimping tool wins on speed, simplicity, and not needing electricity or a certified welder for the seam. Always confirm your project drawings, though, since the engineer may specify a particular side-lap method and spacing that you have to follow.

Where You’ll Use a Deck Crimping Tool

Side laps show up on nearly every deck profile we ship, so a crimper earns a spot on most jobs.

Form deck: The thin, light gauge often makes button punching a natural fit, and a tight seam limits concrete leakage.
Composite deck: Side-lap stitching helps the floor system perform as designed once the slab cures.
Roof deck: Crimped side laps develop the diaphragm and keep the roof surface tight for the membrane or insulation above.

Whatever profile you’re running, the side lap still needs to be fastened at the intervals your drawings call out. The tool just makes that step faster.

Tips From Our Crew for Cleaner Crimps

Over the years, we’ve picked up a few habits that separate a clean side lap from a sloppy one:

Seat the lap first. Make sure the male and female edges are fully engaged before you crimp. A partial lap makes a weak button.
Follow the spacing on the drawings. Don’t eyeball it. The specified interval is part of the diaphragm design.
Match the tool to the gauge. Heavier deck needs more force. A manual tool that’s perfect on light form deck may struggle on thicker stock.
Inspect as you go. A good button is fully formed and tight. If it looks shallow or torn, redo it.
Keep the tool clean and lubed. Grit and dry pivots wear out a crimper fast and produce inconsistent connections.

Rent or Buy? When a Rental Makes More Sense

Here’s where we can genuinely save you money. A powered crimper or specialty deck crimping tool is a real investment, and if you only need it for one floor plate or a single project, buying it outright rarely pencils out.

That’s why Keystar offers tool and equipment rentals. You can rent the crimping tool for the job, knock out your side laps, and return it, without tying up capital in a tool that sits in the shop the rest of the year. For contractors who run decking work all the time, owning may still make sense, but for everyone else, renting is the smart play.

Because we’re a locally owned and operated supplier in Eagan, MN, you can get your deck and your tools in one stop. We offer same-day or next-day shipping and pickup, cut-to-order deck, and a full line of accessories to round out the order. Pair the right deck from our product lineup with a rental crimper and you’re set to go.

Safety and Quality on the Deck

Crimping is low-drama compared to welding, but you’re still working on an elevated steel surface with a tool that applies a lot of force. Standard fall protection, hand protection, and jobsite practices all apply. OSHA sets the baseline for working safely at height and around steel erection, and your site’s safety plan should align with it.

On the quality side, the best insurance is the right tool matched to the right deck, used the way it’s meant to be used. That’s the part where talking to a supplier who actually knows decking pays off. We’re happy to talk through your profile, gauge, and side-lap method before you ever set foot on the deck.

Frequently Asked Questions

What is a deck crimping tool used for?

A deck crimping tool fastens the side laps of adjacent metal deck sheets by crimping or button punching the overlapping edges together. It locks the panels into one continuous surface so the deck can develop diaphragm strength, all without welding or screws at the seam.

Is button punching as strong as screws or welds for side laps?

Button punching is a recognized side-lap fastening method, and when it’s done correctly at the spacing your drawings specify, it develops the connection the design calls for. Always follow your project’s engineered details, since the engineer of record may require a specific method and interval.

Does a deck crimping tool replace support fastening?

No. A crimping tool handles the side lap between supports. Fastening the deck to the frame (the joists or beams) is a separate step done with welds, screws, or power-actuated fasteners. You need both to meet the design.

Can I rent a deck crimping tool instead of buying one?

Yes. Keystar offers tool and equipment rentals, so you can rent a crimping tool for a single job and return it when you’re done. For one-off or occasional work, renting almost always beats buying. Call us at (651) 256-0008 to check availability.

Which deck types need side-lap crimping?

Form deck, composite deck, and roof deck all have side laps that need fastening at specified intervals. The exact method and spacing come from your project drawings and the diaphragm design.

Where can I get steel deck and a crimping tool in Minnesota?

Keystar Industries at 1920 Shawnee Road, Eagan, MN supplies USA-made roof, composite, and form deck along with accessories and rentals. We offer same-day or next-day shipping and pickup, plus cut-to-order service. Call (651) 256-0008 or request a quote online.

Ready to Lock Down Your Side Laps?

Don’t let side-lap fastening slow down your install. Whether you need the deck, the tool, or both, we’ll get you set up fast. Rent a deck crimping tool, request a quote, or call us at (651) 256-0008. Our team in Eagan, MN knows steel deck inside and out, and we’re ready to help you spec the right product and tool for the job.

Request a quote or contact our team today.