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What Is Punchlok? Types & Uses Of Punchlok II Metal Decking
Paul Rubio

By: Paul Rubio on December 12th, 2019

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What Is Punchlok? Types & Uses Of Punchlok II Metal Decking

Metal Deck | PunchLok II

How would you like to save a ton of time and money on your next metal roof deck project? Punchlok II has the ability to eliminate top seam welds and allows for the use of a lighter gauge steel in many instances. However, it is not right for all applications. In this guide we will explain the Punchlok II system and the VSC2 side lap connection. We will specifically talk about whether it is correct for a roof deck or a floor deck application.

What is Punchlok?

Punchlok II is a metal deck system that has the highest diaphragm shear values, requires less welding, and reduces the steel deck gauge. It's the evolution that replaced top seam welds. Punchlok II is essentially normal metal decking, but the side lap is attached with a Punchlok II tool instead of a button punch.

The PunchLok II tool is a pneumatically operated, hand-held, tool that joins metal decking sidelaps of the PunchLok II system.

This is a patented system and it can only be used on Verco or Vulcraft metal decking. Punchlok II is the second generation of this system in which the latest tool redesign has larger jaws and is more efficient. It replaced the original Punchlok metal decking. Verco Punchlok II is normally specified on the West Coast and Vulcraft Punchlok II is specified throughout the remainder of the country.

What Is A VSC2 Sidelap Attachment?

When you use a Punchlok II tool to crimp the sidelap of Punchlok II decking it's called a VSC2 which stands for Verco Sidelap Connection Version 2. The VSC2 connection improves the shear values of the decking when compared to a typical button punch side lap. These factors create an opportunity to lower labor and material costs.



Punchlok Roof Decking

Punchlok II metal decking is primarily used for metal roof deck applications. The main benefit of this system is the greater shear values created by the VSC2 side lap connection. Increased shear values apply to a roof deck condition and NOT a floor deck condition.

Punchlok II is not a weather tight system. When the tool fastens the side lap it will penetrate the material and it will leak 100 percent of the time. It is intended to be used in an application in which a built up roof will be installed over the metal decking.


Can you use Punchlok II on a Canopy?

You should NOT install Punchlok II metal decking for a canopy. Canopies are designed to be as weather tight as possible. You can see from the image below that Puncklok II will leak at the side lap connection. If you have a canopy installation you should use button punch side lap metal decking such as: HSB-36, N-24, or HSN3

punchlok-connectionPunchlok II sidelap connection


button-punch-sidelap-connectionButton Punch sidelap connection


Punchlok Floor Decking

Punchlok II metal decking is rarely used for metal floor deck applications. When you pour concrete on metal decking and create a composite system the Punchlok II side lap connection has a minimal effect on the engineering values. It was NOT intended to be used on a floor deck application. The main benefit of this system is the greater shear values created by the VSC2 side lap connection. Increased shear values apply to a roof deck condition and NOT a floor deck condition.

If you have further interest: Metal Deck: Floor Deck Vs Roof Deck


Can you use Punchlok II as a composite floor deck?

Punchlok II floor deck is fine to use in a floor deck application, but there are minimal benefits when compared to a button punch side lap. The main benefit when using Punchlok II instead of button punch is the consistency of the side lap connections. However, it is NOT important enough that it should change what type of metal deck is specified. What normally happens when Punchlok II is specified on a job is that the engineer is familiar with the Punchlok II system and by default everything that they specify becomes Punchlok II. I would NOT recommend using Punchlok II floor deck on a small job.

To learn more about the disadvantages of Punchlok II: Here are the 5 problems when using Punchlok II on small projects.



When used in the correct conditions, Punchlok II is the time-saving metal decking answer. It can also potentially save your project a substantial amount of money by using a lighter gauge steel and eliminating stitch seam welding of the metal deck.

However, Punchlok II is not always the right choice for metal decking. You should not use Punchlok II for:

  • Small jobs under 10,000 square feet
  • Floor deck jobs

The best projects to use Punchlok II for are roof deck jobs that are larger than 10,000 square feet.

At, we have all types of metal decking in stock including Punchlok II tools. Our sales staff consists of experts that have experience installing and detailing metal decking that are happy to answer any of your questions.

To get started using Punchlok II, request a free quote today and a member of our knowledgeable sale team will be in contact with you.


Want more information on Punchlok tools or other metal deck products? Check out our Metal Deck Learning Center.

Visit the metal deck learning center today!

About Paul Rubio

Paul Rubio is the Vice President and one of the owners of Western States Metal Roofing. He has been in the metal roofing industry for 25 years. WSMR is a manufacturer of metal roofing, wall panels, and metal siding. We have colors and finishes that nobody else has with nearly 100 different colors in stock. Our selection of color options and finishes is likely the largest in the industry.