Metal Deck For Concrete: Types & Uses of Composite And Form Decking
Do you have a job that requires metal decking for concrete? It might surprise you that there are a lot of factors that go into purchasing the correct metal decking for your project. If you install the wrong type of metal decking the building can collapse.
Fortunately, you don’t have to guess which metal decking to use for your concrete slab. An engineer will specify the type of metal floor decking and the correct gauge. Where do you come into play? You need to know where to look within the plans and what to tell your metal decking supplier when you order the steel decking.
At Western Metal Deck we’ve been selling composite metal decking for thirty plus years. Since we are regularly asked about steel form deck and composite floor deck, we know it’s probably something you might be asking yourself. Instead of having to speak to a salesperson or feel like you’re lost in the dark, we wanted to provide a thorough analysis of composite floor deck to help you make sure you install the right type for your job.
In this article we will cover:
- Metal Decking Specifications
- Composite Floor Decking
- Types Of Composite Floor Decking
- Metal Form Decking
- Types Of Form Decking
- Types Of Concrete
- Gauges Of Metal Floor Deck
- Metal Floor Decking Costs
Metal Deck Specifications
First things first, metal deck specifications are the section of the construction drawings in which the engineer will specify the metal decking that will be used. If you have a metal decking job, but don’t know what type of metal deck to use, then this is where you look.
You’ll find the type of metal decking, gauge, finish, and much more. It’s not your responsibility to design the job and keep the building from collapsing. That’s the responsibility of the engineer. All you have to do is supply the correct material that was specified for the project.
Now you’re probably asking yourself where are the specifications located within the plans, what else is in the specifications, can you change a specification, or exclude items. We answer all of these questions in this easy to understand article.
What Is Metal Decking For Concrete?
Metal decking is a corrugated sheet metal that’s supported by steel joists or beams. Concrete is then poured on top of the metal deck and it becomes either a composite floor deck system or a steel form decking.
What's Corrugated Metal Decking?
Corrugated metal decking is just another term for either steel form deck or composite floor decking. It's simply corrugated metal that's designed to have concrete poured on top of it.
What’s Composite Floor Deck?
Composite floor deck is a corrugated metal deck that has embossments in the flutes of the metal decking. As the concrete slab cures, the metal deck and the concrete bond together to create a composite metal floor deck.
This is the most common type of metal floor decking. The main advantage of a composite metal floor deck is that it will increase the strength of the floor without adding extra weight.
For a deeper dive into composite floor deck we recommend:
Types Of Composite Steel Deck Concrete Floor Systems
There are three main types of composite steel decking. The trade names and manufacturers of the composite floor deck will vary depending on where your project is located. However, regardless of the manufacturer, the composite deck will be 1.5”, 2”, and 3” in depth.
The combination of the depth of the floor deck and the gauge of the steel will determine the panel strength and engineering values. Floor decking with a greater depth and a heavier gauge will be stronger than metal decking that’s shallower or a lesser gauge.
For example, 3” composite floor decking is stronger than 2” decking in the same gauge thickness.
B Composite Floor Decking - 1.5” Deep
This type of metal floor decking is 1.5” in height and quite often referred to as “B” or “Type B”. It’s the lowest profile composite floor decking and is capable of the shortest spans.
2 Inch Composite Floor Deck
Every manufacturer calls 2-inch composite floor deck something different, but you will normally see a “2” somewhere in the description. For example, Verco Decking calls their steel decking W2 Formlok.
2-inch composite floor decking can handle thicker concrete slabs and span further distances compared to 1.5” metal floor deck.
3 Inch Composite Floor Deck
3 inch composite floor deck is the deepest composite floor deck that’s readily available. It’s the strongest metal floor deck and can span the furthest. You can also pour a thicker concrete slab vs. a 1.5” or 2” floor deck.
Other Types Of Composite Floor Decking
The vast majority of metal decking with a concrete slab will be one of the three types mentioned above. However, there are instances in which you need to span further and carry a greater load than conventional floor decking can accommodate.
There is a specialized type of composite floor deck that’s known as “Deep Deck”. This type of metal deck is available in three sizes: 4.5”, 6”, and 7.5”. It’s a very expensive product that requires a long lead time.
What’s Metal Form Decking?
Metal form decking is smooth corrugated metal sheeting that does not have embossments in the flutes of the panel. It acts as a stay-in-place form that will support the wet concrete and does not need to be removed after the concrete has cured.
Metal form decking is not a composite metal floor deck. It doesn’t become bonded to the concrete. It’s only a form that will support the weight of the concrete and does not increase the strength of the floor.
For a deeper dive into metal form decks we recommend:
Types Of Form Decking
There are two main types of metal form decking. They go by different names and even are slightly different depths. Generally, they will be about ½” deep or 1” deep.
On the West Coast, the two types of form decking are 9/16” or 1 5/16”
9/16” Form Deck - Shallow Vercor
Shallow Vercor is the lowest profile form deck and can support the least amount of weight. This is the least expensive type of form decking.
1 5/16” Form Deck - Deep Vercor
Deep Vercor is a higher profile form deck. It’s capable of longer spans and can support more weight. Because it’s normally heavier gauge steel and costs more than Shallow Vercor.
Metal Decking Concrete Slabs
Metal decking concrete slabs will normally use structural concrete. This type of concrete will add strength to the structure. It’s available as a normal weight concrete, 145-155 pounds per cubic foot, or lightweight concrete, 110 pounds per cubic foot. The engineer will determine which type will be used on your project.
For a deeper dive into concrete for metal decking we recommend:
Metal Deck Gauge Thickness
Gauge refers to the thickness of the steel. As the number gets lower the thickness of the metal gets heavier. For example, 20 gauge metal decking is heavier than 22 gauge steel decking.
- Composite Floor Decking - Available in 22, 20, 18, and 16 gauge.
- Metal Form Decking - Available in 26, 24, 22, and 20 gauge.
For a deeper dive into metal decking gauges we recommend:
Metal Floor Decking Prices
Metal floor decking will cost $2.50 to $5 per square foot. The pricing will vary based upon the following factors:
- Type Of Metal Deck
- Size of job
If you want a more detailed explanation of metal decking costs we recommend:
Where Can I Buy Metal Decking For Concrete?
Once you’ve determined the type of metal floor deck that’s specified on your job, you will see that metal decking is not an easy product to find. There are only a few businesses in each region that offer it.
If you want to buy metal decking, you have two choices. Buy direct from the steel mill or use a metal decking distributor. Unless you already have a relationship with the steel mill, they will rarely allow you to purchase factory direct. Instead, they will refer you to a metal decking distributor.
We can save you the time of searching online and we can ship anywhere within the United States. If you need metal decking quickly, we have you covered. We have composite and form decking in stock and provide immediate delivery to your jobsite.
Discover how to purchase metal decking:
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.