Installing metal deck is not a simple process. From landing the deck in place, spreading it, temporarily and permanently fastening it, to attaching the side laps, the installation of metal deck is hard work.
Before you start attaching the sidelaps, you should permanently fasten the metal deck to the structural framing. Fastening the metal deck can be achieved by three different methods: self-drilling screws, welds, or by powder driven fasteners. The manner in which you end up fastening the metal deck to the structural framing will typically depend on what the engineer has specified in the plans.
While we can’t install the metal deck for you, we can guide you through the different methods of fastening the metal deck. As a supplier of metal decking for over 30 years we at Western Metal Deck have seen each method specified and walked clients through the installation process.
In this article, you’ll learn about each of the fastening methods. It’s important to keep in mind that you should always fasten metal decking based on the specifications of your plans.
Fastening Metal Deck With Self-Drilling Screws
Self-drilling screws are a type of screw that performs as its name implies. The screw drills through the metal deck and into the structural framing.
A screw gun is used to drive the self-drilling screw through the metal deck and into the supporting frame. If you will be installing a lot of metal deck you want to be sure to have a good screw gun. On smaller jobs a cordless hand held screw gun is often preferred by metal deckers. On jobs over 10,000 square feet, a stand up screw gun is preferred.
Attaching the deck to the structural framing using self-drilling screws is not a common attachment method. However, when it is used, it is used mostly on a roof deck system, not on a floor deck system.
Fastening Metal Deck By Welding
Welding the deck to the steel framing is a very common call out. This type of weld is commonly referred to as a plug weld. The plug weld must always be completed by a light gauge certified welder.
The process of welding metal decking to the steel framing is done by using a welding machine and a weld rod. Using a weld rod you burn through the decking into the steel beam below and make a puddle weld about the size of a nickel.
Once done, you pull the weld rod out and do it again. The whole process takes about 5 seconds per puddle weld. A puddle weld is simply a puddle of molten metal which hardens almost instantly. Lincoln weld rods are one of the more popular weld rods used by metal deckers.
If you’re welding galvanized decking, be sure to use a mask respirator. The zinc fumes created when welding the galvanized decking can be poisonous.
Fastening Metal Deck With Power Driven Fasteners
Using a power driven fastener is common on both roof and floor deck systems. A powder actuated tool and pin are used in this attachment method.
A power actuated tool operates similarly to a gun. The tool has a charge, when triggered it pushes the piston. The piston then slams the pin through the decking and into the steel beam. A different size pin may be called out for different decking systems. A roof and floor deck may have two different sized pins specified. Hilti is normally specified on projects, they carry both the tool and pins.
What To Do After The Deck Is Fastened
Fastening the metal deck to the structure is, needless to say, a very important step. It provides a steady platform and keeps your metal deck from shifting around. It’s common to fasten the metal deck down prior to attaching the metal deck side laps. Attaching the sidelaps can cause the metal deck to move slightly causing potential problems. If you fasten the deck to the structural framing this helps to prevent that shift.
Once you have fastened the metal deck, your next step should be to attach the metal deck side laps. Just like you have to follow plans to determine the fastening method for metal deck, you will need to refer to the structural drawings to determine what is specified and engineered.
Depending on the type of sidelap you may only have one option on how to attach the sidelaps, such as a stitch screw side lap. With this type, you can only attach the side laps using a stitch screw. However, if you have a standard interlocking side lap, the sidelap attachment method will depend on what is specified.
To learn more about metal deck side laps check out:
Common Metal Deck Sidelap Types & Connections
