Every so often a metal decking job includes the design of an inverted/reversed metal deck. This metal decking is not typically used in construction projects, however, it’s extremely important to understand what this means if inverted or reversed metal deck is included in your project because a small mistake could cost a lot to fix.
In this article, we will explain exactly what inverted/reversed metal decking is, the different types of inverted/reversed metal decking, and how to install inverted/reversed metal decking.
What is inverted a.k.a. reversed metal decking?
An inverted/reversed metal decking is metal decking that’s meant to be installed upside-down. An inverted or reversed metal deck that is installed upside-down may not be as strong as traditional applications of metal deck and can’t always span the same distance, however, in certain applications, reversing your metal deck can create a stronger concrete slab or look nicer.
Types of Inverted/Reversed Metal Decking
Inverted metal decking is possible with roof, floor, and form deck. Within each specification, there are more popular options and other, less common, applications.
Roof Inverted/Reversed Metal Decking
An inverted/reversed metal roof deck is commonly seen on trash areas to protect dumpsters from the rain and on commercial loading docks.
You will usually see type 1 5/16” deep and 9/16 shallow metal decking used for inverted/reversed roof metal decking applications. These metal decking options come with a nestable sidelap. When installed in an inverted position, the sidelaps end on the high side of the panel.
Another popular option is a type B deck with a nestable sidelap. These are often used for canopies or trash cover jobs. When the type b roof deck is installed upside down, the nestable sidelap is placed on the top side of the sheets.
In roof deck applications, panel leakage is heavily reduced by placing the nestable sidelap on the high side of the sheet. This can be reduced even more by calking the sidelap or by creating a double-sided lap and calking the sidelaps. It’s important to note that the sidelap is attached by using stitch screws.
The roof inverted/reversed metal decking application method will likely result in ongoing minor leakage, and this is why it’s intended for canopies and trash areas, where leakage is not a problem. It is very important to note that inverted or reversed roof deck installation can’t be used as roofing or building in areas that need to be waterproofed and keep rain out 100% of the time.
Floor Inverted/Reversed Metal Decking
An inverted/reversed metal floor deck is commonly used when the project needs a stronger concrete slab and commonly utilizes composite types 1 ½ B deck or 3” N deck.
A composite deck type B is the most common inverted/reversed metal decking option. This composite deck helps create a strong slab and you will usually see it paired with deeper panels such as 2″ Composite or 3″Composite. In case the engineer needs to save space, there’s also the 1.5” deep type B deck option available.
A composite deck type N is not often seen, however, it is possible inverted/reversed metal decking method. These have less availability and can hold less concrete.
Key Notes on Inverted/Reversed Metal Decking Installation
You have to keep in mind that, though you are performing an upside-down installation for your metal deck, the supplies will be shipped right side up. While spreading the metal deck, every sheet must be manually turned upside down to have a proper inverted/reversed metal decking installation.
When placing your metal decking order, you need to properly indicate the sidelap connection method you will be using. There are commonly 3 different types of sidelaps that can be used: stitch-screw, standard nestable, and standard interlocking. The sidelap connection method is very important for an inverted/reversed metal deck project, so you need to make sure you select the appropriate sidelap connection method.
Stitch-Screw Fastened Sidelap
The stitch screw sidelap connection is a common option when performing this type of metal decking project because it can be done from the top just using a screw gun.
Standard Nestable Sidelap
The nestable sidelap uses stitch screws for the attachment. When placing a form deck, the panel can be installed upside down so that the sidelaps can be attached from the top.
Standard Interlocking Sidelap
The standard interlocking sidelap is the most difficult to attach upside down. After the metal deck is turned upside down and properly installed, you need to go under the metal decking and then attach the sidelaps, making this an uncomfortable project.
Inverted/Reversed Metal Deck from CSM
Whether you need guidance on what type of metal decking to choose or you’re ready to place an order, we highly recommend working with our team to ensure the best pick and the fastest delivery possible. At CSM Products & Solutions, our team has all the tools and experience to make sure your project is a success.
Contact us today for more guidance on metal deck closures or to place an order.
