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Grooved Or Ungrooved Boards

  • Luke
  • May 1, 2019

Now that you have decided on your composite decking product, colour and size of boards you require, your next question may be grooved or ungrooved finish.

The Differences between Grooved and Ungrooved Boards

If you want to purchase a composite decking board, you will have to select either a grooved or ungrooved board for a clean finish. Homeowners new to installing composite decking might not know which decking types will give a clean finish. What is the difference between the two decking designs? That’s what we will let you understand

1 What Are Grooved And Ungrooved Boards?

The differences between grooved and ungrooved are in the construction of grooves on each side of the composite decking board. A solid board will more than likely be an ungrooved finish and a hollow board will most likely have a grooved finish. These two differences do change the look of your decking and installation.

Grooved composite decking boards come with an indent or a grooved row along each side of the board. Most newer designs of composite decking boards will typically have this indentation.  

On the other hand, there are also ungrooved composite decking boards that don’t have grooves on each sides. For the past few years, this is the type that most people have been using to install their new decking area. Because of this, it is often associated with older generations of composites. However, most existing ungrooved decking boards are indeed likely from the first generation of composites. That’s not to say that all of them are old, as there are still ungrooved boards in production and used by many.

So, what is the purpose of the grooves on the decking board?

2 Why Do Some Decking Boards Have Grooves?

You’re wrong if you think that the grooves are only there for design purposes. The truth is, they serve an important role in securing the decking boards in place. 

The oldest way to secure the boards to the frame was with the use of nails or screws. Many people still use this method. However, a new fastening system was invented, which does not require screwing or punching nails through the top of the boards. Instead, they are hidden from plain sight. Not only is it safer, but aesthetically pleasing as well, since you’ll have a deck with no visible screws.

However, to use a hidden fastening systems, you will need grooved decking boards. The system uses a series of clips and fasteners that fits into the indents or the grooves on the side of the composite decking boards. This is the purpose of the grooves on newer designs of composite decking boards

Now you know what they are for, it’s now time to choose which one to use. Is it better to use grooved decking boards or ungrooved ones? Of course, each of them has its advantages.

4 Why Use Grooved Decking Boards?

For grooved decking materials, you can have a decking area without any visible screws, nails, or holes from punching them into the boards. Because of this, the decking will look cleaner and smoother. For many, this is a huge plus. 

Apart from creating a clean finish, another reason to use them is safety. While screws and nails have been used for a long time, they do have some issues. Especially the nails, they tend to resurface because of the expansion and compression of the material due to moisture. While this is not a significant issue with composites, it can still happen. When the nails back up, it poses not only damage to the deck but also safety problems. People may get injured due to it. So if you want a decking area with a beautiful clean look, grooved decking boards are for you. They are also easy to install and are generally the safest.

5 How Easy Is It To Install A Grooved Board

Grooved decking uses a connection system in which clips onto the groove of the board and then screws into the joist to fix in place. With this installation connection you can also purchase hidden fasteners. In the hidden installation method, the fasteners will hold down the grooved sides of the composite decking, thereby concealing it from the top. You can conceal the fasteners so that it is not visible if you look at the composite decking from the top.

With an ungrooved board, you will drill the composite deck boards with screws from the top of the board which will be visible.

Grooved boards are the ideal choice for most customers. Which was the main reason and our choice when manufacturing our ultra decking products. Grooved boards produce a more polished and neat finish once your installation is completed. The beauty of the wood grain pattern truly takes centre stage with no visible screws on display.

Installing grooved boards with a hidden fastener system will increase safety at your home or commercial property. Children, pets and clients will never have to deal with surface nails coming into contact with bare feet

6 How Easy Is It To Install A Grooved Board

As previously mentioned, people may associate ungrooved with the old generation of composites. Because of this, some may think that they are not a viable choice for decking. However, this is not true. Sometimes, using ungrooved ones is better. 

For instance, it’s better to use ungrooved if you’re building an outside deck on the upper floors. Since grooved decking leaves gaps between the boards, water can pass through the deck easily.  Using ungrooved, any liquid spills on the deck or rain will not drip quickly. The gaps made by the grooved decking boards also pose another safety issue. If wearing heels or any similar footwear, there’s a chance you’ll trip on the gaps.

Another good reason to consider ungrooved is that there are ways to hide the screws and nails. You don’t have as many options as grooved boards, but getting a smooth and clean-looking deck is still possible. One way is by plugging the holes left by the screws. 

7 How Easy Is It To Install Ungrooved Board

The ungrooved composite decking is also known as the solid edge decking. It is a composite decking that differs from grooved decking because it does not have channels by its sides. The ungrooved decking has a smooth edge making it possible to drill screws into the top of the boards to fix them into place.

To install ungrooved boards you will simple pre drill holes 2-3mm bigger than the screw head and fix into place, you can do this from the top or from the sides fixing the screw into the board and the joist to hold in place.

When you look at the decking from the top, you will see that the screws are visible. It implies that the screws will appear on the surface of the decking after you have installed it.

Ungrooved decking doesn’t require the use of fasteners like grooved composite decking. The good thing about ungrooved decking is that there are fewer gaps between the decking. Fewer gaps between the boards allow your kids and pets to play around with your decking safely. Fewer gaps between the boards can also equate to a smoother surface, providing a better visual appearance in some views

8 Should You Use Grooved Or Ungrooved Composite Decking

If you want a clean finish for your deck surface, you should go for a grooved composite decking board. However, if you use ungrooved decking, you can paint the deck screw to match the decking. However, this will not create a clean finish like grooved composite decking boards can.

However, purchasing an ungrooved board is not the best choice for homeowners who desire a clean finish. It does not mean that ungrooved decking is useless; using ungrooved boards also has its benefits. Choosing between grooved and ungrooved composite decking should reflect your aesthetic tastes and functional needs. Some decking designs even require both grooved and ungrooved boards. For instance, if you want to picture-frame your deck, you can use both decking types. You can frame your decking with grooved boards to produce a finished edge.


Choosing between grooved and ungrooved composite decking  should reflect your personal preference and taste. Grooved decking is a good option for homeowners who want a clean decking finish. When buying and looking for composite materials, you will notice that not all of them are the same. They differ in size, colour, and in construction. The one notable difference is a grooved or ungrooved board. The choice is yours.

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