Enjoy A Fire Pit on Your Trex Deck: Safety Considerations

There are few better ways to entertain your friends and family or relax in your backyard than enjoying each other’s company by a fire pit. The welcoming warmth, flickering lights, and sense of community provided by a fire pit make it one of the most valuable additions to a landscape. You may be wondering how you can include a fire pit on your Trex deck. The good news is that with a few precautions and the right fuel choice, you can certainly enjoy a comforting fire in practically any social space or corner of your landscape, including your Trex deck.  In this article, we’ll go over the things you’ll need to know about putting a fire pit on your deck, including specifications, restrictions, and additional products. 

Is Trex Decking the Same as Composite Decking?

Yes. Trex was the first company to introduce composite decking materials to the market and for some time, Trex was the only manufacturer. As a result, the Trex name is intertwined with any mention of composite decking. Their products remain at the top of the industry for quality decking materials.

Is Trex Decking Fireproof?

Fire resistance ratings are determined by Underwriters Laboratories, an independent consumer safety company. An "A" rating indicates a high level of fire resistance, while a C rating refers to an average level of fire resistance.

Trex has designed all of their decking lines to be certified fire resistant, greatly enhancing the safety of your decking and giving you the ability to install a fire pit. In fact, the Transcend and Select decking lines from Trex are certified Class B fire resistant. Most Trex decking is classified as a Class C, or Class III, building material. This means that Trex boards will burn like wood, even though each board contains plastic and other materials. Therefore, in the event of a fire, a Trex lumber will burn just like the wood.

However, Trex also features a special Fire Defense board which adds fire resistance. Unlike standard Trex decking which contains wood and plastic, Fire Defense boards contain 50 percent wood and 50 percent polyurethane. While polyurethane still burns, it burns more slowly. This makes Fire Defense boards burn more slowly than wood. Fire Defense boards are a good idea if you plan on installing a fire pit on your deck. 

What’s the difference between fireproof and fire resistant? Both fireproof and fire resistant refer to a material’s ability to prevent the spread of flames. Fireproofing chemicals are applied to surfaces to stop flames from reaching the flammable material inside as long as the intensity of the flame is still low. If a fire grows too intense, even the most fireproofed materials will burn. Fire resistant materials, including Trex decking, may burn if directly in contact with flames for a sustained period of time. However, fire resistant materials are designed to self-extinguish once the source of the flame is removed. 

Can You Put a Fire Pit on Trex Decking?

Absolutely! There are a few things to consider, however. First and most importantly, the decking material needs to be certified fire resistant. Luckily, all Trex decking is certified fire resistant which means that as long as the flames don’t come in direct contact with the decking material, it’s safe to have a fire pit on your deck. This brings us to the second consideration: fuel.

Making the Right Fuel Choices

A fire pit can be fueled by wood, natural gas, or propane. Each has its own benefits and drawbacks. 

Wood produces the most heat and flying embers can be a hazard. Of course, the biggest concern is that the high heat produced by a wood-burning fire pit could damage a Trex deck since the composite material is a mix of wood and plastic. While wood fire pits provide that classic campfire experience, they provide a variable range of heat that can be hard to manage. Wood burns at a high temperature and a core of burning embers can retain that heat for upwards of 12 hours. 

What most people don’t realize is that heat also travels downward, which can seriously damage the decking below the fire pit (and it doesn’t matter what material the fire pit is; all fire pit materials conduct heat. 

If you want a wood fire, we recommend a three-way approach. First, use a thick base of sand on top of concrete blocks at the base of the fire pit. Second, you could also build a non-flammable hearth around the fire pit using pavers or tiles. And third, ensure that the flames are completely extinguished when the fun is done instead of allowing the embers to continue producing heat.

Natural gas and propane fire pits are inherently much safer since the flames can be extinguished with the turn of a dial, and portable fire pits typically come with either a stand or a heat shield so they can be placed on any surface. Propane- and natural gas-fueled fire pits also burn at a lower and more easily manageable temperature that is much better suited for sitting atop a deck. 

What Kind of Fire Pit Can You Put on Trex Decking?

There are multiple types of fire pits that are used in landscape design. The differences between each come down to the shape, the material used to construct the fire pit, and the fuel. Fire pits are most commonly found in simple shapes such as circles or squares, but you can find rectangular or oval shapes as well. The material used to construct the fire pit can be masonry blocks, poured concrete, or metal. This is a decision that largely comes down to the amount of space available and your design aesthetics. Any of these can be placed on Trex decking with the right precautions.

How Do You Protect Trex Decking from a Fire Pit?

Even with the choice of a fire resistant decking material which is infused with fireproofing chemicals, it’s still important to take steps to protect the deck. Every fire pit should be at a safe vertical distance from the decking surface. This separation between the heat source and the decking material will protect the surface. Added buffers, such as a fire pit stand or a layer of bricks or pavers can greatly reduce the amount of heat transfer.

Your biggest ally in protecting a Trex deck from fire damage is a buffer zone. This empty space without flammable materials will contain the flames if anything happens and reduce the amount of heat damage that could occur after prolonged burning. Every fire pit needs to be at a position that keeps it at a safe distance from anything flammable, as well as the home. The edge of your wood-fueled fire pit should be at least 10 to 15 feet away from your home as well as other flammable objects such as fences and trees. A natural gas or propane fire pit can be much closer since the flames are not as tall and there are no sparks or flying embers to deal with.  

Fire resistant chemicals can and should be applied to the wood structural elements underneath the decking,  

Is There a Product that Improves A Deck’s Fire Resistance?

While there is no decking material that is 100% fireproof, we’ve outlined some measures you can take to make your Trex deck safe while enjoying the fire: make sure there’s a heat shield under the fire pit and a safe zone of non-combustible materials around it (if it’s a wood-burning fire). 

Install a fire pit of your choice, make sure your Trex deck is well protected from heat radiating downward, and of course, always have a fire extinguisher handy no matter what type of fuel you’re burning.