A warning on wood about using a fire pit on decking that says fragile

The Ultimate Guide To Using a Fire Pit On Decking

A common concern of portable fire pit owners and would-be enthusiasts is whether or not you can use a fire pit on decking.  Concerns for both wood and composite decks span from basic fire risk to warping, to cosmetic damage to a host of other issues. 

If you’ve ever built a backyard deck, you know how expensive it can get, even if you do it yourself.  Add composite decking like Trex or Timbertech to the mix and you’re in a whole new price range.

Having a good understanding of potential risks and what information you need to evaluate them will go a long way in helping you protect your valuable desk investment while guiding you in choosing and placing a fire pit that meets all of your needs.  

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Fire pits, both wood-burning, and gas can be used safely on wood or composite decks provided they are placed a sufficient distance from adjoining structures such as the home, and a heat-resistant barrier is used between the fire pit and the deck to prevent potential structural and cosmetic damage due to the high-heat environment.

Having a stable (and level) spot, that’s close to the house, is a must-have for many.  Being able to take advantage of a well-lit space, with close proximity to the kitchen, bathrooms, etc. is important to some when entertaining.  Knowing how to use a fire pit on decking is not difficult and shouldn’t break the bank.

Note:  For the purposes of this article I’m referring primarily to portable wood-burning and gas fire pits.  Consult a licensed contractor and/or your local fire code if you have questions about installing a fire pit on decking.  There may be specific building code, manufacturer, or other considerations that are unique to your area that will determine which way you’ll be able to go.

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Can You Put a Fire Pit On a Deck?

I think we’ve cleared up this question but, yes, you can safely use a fire pit on decking, both wood and composite if you take certain steps related to fire pit location and having something in between your fire pit and the deck.  More on that below.

What is Composite Decking?

If you are unfamiliar with composite decking, it’s essentially decking that is usually made from a combination of wood fibers, hardwood flour (yes, that’s a thing), polypropylene, polyvinyl chloride (PVC) and other plastics – some brands don’t include any wood or wood byproducts at all. 

The advantages over wood include enhanced durability and resistance to rotting and discoloration. Side note:  It can be uncomfortably hot to walk on in bare feet compared to wood.

With those advantages (…and one minor disadvantage) comes a much higher cost compared to pressure-treated wood, with a price-point between $10-20 per square foot, not including installation. 

I’ve got an earlier version of the Trex brand of composite decking and while it’s still holding up well, the color at this point is not great.

Trex has come a long way since the time mine was installed though.  Other brands include TimberTech, Fiberon, Envision, CaliBamboo, and others. But I digress…

How Hot Does a Fire Pit Get?

A wood-burning fire pit can reach temperatures of up to 1,200 degrees Fahrenheit or 1,100 Celsius (Source: Sciencing.com)

This temp is for a bonfire which is essentially what a fire pit is, with the only difference being that it’s typically off the ground. 

The exception being fire pits where the “floor” of the fire pit is the ground (fire pit rings, etc), the fact of which is moot for this article.  

The point is, it’s very freaking hot and will do a number on your deck if you are not careful.

Fire Pits on Wood Decking

Challenges related to using a fire pit on a wood deck range from full-on fire damage and the destruction or weakening of the decking and the supporting structure, to cosmetic damage from scorching due to metal on wood contact or from hot fire pit contents spilling onto the deck for one reason or another.

If you are or see yourself becoming a regular fire pit user, and you are building a new deck or plan to replace the deck boards (or more) of your existing deck, exterior-use fire-retardant pressure-treated wood (Fire-X brand for example) is an option that provides additional protection to supplement the other steps we’ll cover in a bit. 

Fire Pits On Composite Decking

The concerns with composite decks are similar to those of wood.  Composite decking typically has some fire-retardant properties but will burn as indicated by the information below pulled from Trex’s website.  

Because plastics of one sort on another (polypropylene, PVC, etc.)  are commonly used in composite decking, the risk of warping and melting under high-heat conditions, like those produced by a fire pit, is something to be aware of as well. 

Polypropylene can start melting at 320° F and PVC at 212° F; Trex itself has stated publicly that their “decking will soften as low as 176 degrees Fahrenheit” so you can see why there might be a concern. (Source: Trex Outdoor Fire Pit Statement)

What Does Trex Say About Fire Pits on Decking?

Even with safety being the priority, the cost of replacing damaged composite decking will be costly if certain precautions aren’t taken. 

Below are the specifics from Trex about the fire-resistance of their products, product warnings, and their fire pit barrier recommendation.  

Remember though, each composite decking manufacturer makes their product a little differently, so make sure you check the specs and heed the recommendations of your brand of choice.  

The below applies to Trex brand decking and substructure products only:

“IS TREX FIRE RESISTANT? 

“Our Transcend and Select decking lines retain a Class B fire rating, while our Enhance decking lines retain a Class C fire rating; however, they are not fireproof. Moreover, our substructure product, Trex Elevations®, retains a class 1A fire rating.” (Source: Trex FAQs)

CAN I BUILD A FIREPIT ON MY TREX DECK?

Wood-burning fire pits should not be placed on top of Trex decking unless installed with DeckProtect™, a product designed to temper extreme heat and loose embers. For more information, please visit their website.” (Source: Trex FAQs)

The fire rating classes mentioned in the FAQs are part of a standardized letter classification scale ranging from A-E.  This scale expresses how fast a fire would spread on a particular material, in this case, composite decking boards.  

A on the scale being the slowest to spread, E being the fastest.  Knowing that Trex’s products rate pretty well, particularly their “substructure product” which makes a lot of sense considering that is what is holding everything up. 

Fortunately, Trex doesn’t say no to fire pits altogether and recommends using a barrier between a fire pit and the deck surface – they mention wood-burning specifically. 

I recommend using a barrier on a gas fire pit as well, one that’s not part of a larger fire pit table elevated off the deck’s surface.

Gas fire pits won’t put off as much heat as a wood-burning type but the potential for structural and cosmetic damage is still there.

Again, check with the composite decking manufacturer of your choice for their product specifications and recommendations.

You can read my review of Trex’s recommended fire pit barrier, DeckProtect, here.

What to Put Under a Fire Pit On Decking

Based on our discussion so far, the primary solution to the potential for fire pit heat or ember damage to decking is the use of some kind of barrier. 

There are a variety of do-it-yourself and store-bought options to choose from and it doesn’t have to cost a lot. The return on investment will be worth it no matter what type of decking you have.

DIY Fire Pit Pad

This fire pit barrier option is probably the most inexpensive but isn’t any less effective.  If you have unused pavers lying around your garage or shed, all the better.

After you’ve selected the spot on your deck for the fire pit, simply arrange the pavers in a grid configuration that provides a base to support all legs, or the whole base of the fire pit, however, it’s designed. 

Be cautious when placing the pavers on a composite deck to minimize scratching the surface.  

Be sure to make the paver grid large enough to allow for a little bit of edge around the feet or base of the fire pit just in case its inadvertently bumper and one of the legs is no longer supported by the fire pit.  This will minimize the risk of the fire pit tipping over or sliding off the barrier.

Some recommend just building a paver configuration under the fire pit with the feet of the fire pit touching the deck surface. 

I don’t recommend doing this because the feet will get hot as well during a fire pit burn; you need to isolate the fire pit from the deck to eliminate the possibility of damages. 

Heat-Resistant Fire Pit Mat

Another barrier option for using a fire pit on decking is a heat-resistant fire pit mat.  This is a relatively inexpensive, lightweight and easy-to-store option.

These mats come in a variety of shapes and sizes that should provide adequate coverage for the majority of portable fire pits.

Fire pit mats are typically made of fire-resistant fabric, PVC or rubber material and are commonly available in 24” to 36” diameter configurations for circular mats and 30” x 42,” 30” x 48,” and 36” x 48” configurations for rectangular mats.

I personally recommend going with a PVC or rubber option as they generally have a better record of performance and durability over time.  There are a lot of overpriced flimsy options out there, the round type in particular, so please read the reviews prior to purchasing.

One other thing, be aware of your fire pit’s clearance between the deck and the fire pit bowl.  Some mat manufacturers specify their products will not perform as designed if they are too close to the heat source.

All-Metal Fire Pit Barrier

Another decent option is a metal fire pit heat shield.  These heat shields are probably the closest to a sure-thing when protecting your deck but there is one particular drawback that I have trouble with.  

As far as I can see, these heat shields are only available in 26” x 26”.  Taking a look at the picture, you will see that the heat shield deck of the ground by about 4”.  My concern is that the portable fire pit can be easily bumped off the platform if everyone is not careful.  

There is little “wiggle room” for the legs or base of your typical portable fire pit to go but over the edge, if nudged.  Because of that 4” clearance, there is a risk of the fire pit tipping if one of its legs goes over the side.

Having hot fire pit contents dumped on your feet or worse and your deck is not my idea of a good time.  Keeping an eye out for a larger model in the future.

On the other hand, the use of a fire pit with a round base (not one with legs) like those from the Solo Stove or Flame Genie model range, on this barrier, would work fine IMHO. 

The bases of these fire pit examples maintain 360° contact with any surface, providing greater resistance to tipping. Just my thoughts.

Insulated Fire Pit Barrier

This is the DeckProtect fire pit barrier recommended mentioned previously (see my review of the barrier here).

These fire pit barriers come in both square (in 12” x 12”, 16” x 16”, 24” x 24”, and 36” x 36” sizes) and octagonal (30” diameter) configurations.  

The barrier is essentially a ventilated metal tray elevated about a half-inch off the ground by 5 rubber/plastic “feet.  In the tray is a combination of heat-resistant natural and man-made fibers on which the fire pit will sit.

These are not the most aesthetically pleasing of the fire pit barrier options out there, but the reviews are generally solid and the Trex endorsement should definitely be a consideration when shopping for deck protection.  

Unlike the all-metal platform option mentioned previously, there are a variety of sizes available to accommodate most sizes and types of fire pits, with additional space on the edges to allow for some intentional/unintentional movement of the fire pit without the tip-over risk.

Paver Safety Base

This option is basically a collapsible iron frame (yes, iron) which is designed to hold 9 16” x 16” inch pavers (which are not provided in the package), providing a 50 sq in. (3” thick) surface on which to place a fire pit.

For me, this is the most solid option of the ones I’ve mentioned.  This barrier will protect your deck, is large enough to minimize tip risk, and has the best look hands down.  What I don’t like is the price, currently around $200.  

With that said, you’ll most likely have it forever and you can customize the look by selecting paving stones that satisfy your tastes.  This option definitely looks less out of place with the typical deck decor than the other options mentioned if that type of thing is important to you.

How Close Can a Fire Pit Be to a House?

When choosing a spot for your fire pit it’s generally recommended that it should be located approximately 20-30 feet from structures, your home in particular.

The challenge here for most, myself included, is having a deck that can accommodate that kind of structural standoff.  My deck at home is just barely in this range and I wouldn’t consider mine a large one.  

Check with your local fire department and/or local fire codes for directives specific to your area.

Where to Put a Deck Fire Pit

Once you have a general idea of where you are going to put your fire pit, consider the following when narrowing down your options:

  • Position your fire pit in a relatively low-traffic area to reduce unintended contact with the fire pit or its hot contents
  • Be aware of and position your fire pit away from overhead structures (i.e. roofed-in patio, awnings, etc.) and tree branches that might encroach on the area above spots in consideration – trim back tree branches as necessary to facilitate placement;  fire pits can be used in covered areas but the overhead structure may need to be modified or built to local code to accommodate fire pit use
  • Select a spot that can accommodate seating positioned 3-5 feet away from the fire pit in all directions
  • Choose a spot where access to the fire pit can be easily monitored and controlled, particularly if children or pets will be present

If you are interested in reading more about safe fire pit placement, check out my article dedicated to the topic here.

Best Fire Pits for a Deck

When selecting a wood-burning fire pit for your deck, especially one made of composite decking, strongly consider fire pits that come with a spark screen or can be fitted with a third-party option. 

Sparks emitted from burning firewood are capable of creating minor pitting in a composite deck. A spark screen will minimize this risk.

Firewood Note:  To minimize sparking, common seasoned hardwoods like black locust, oak and hickory should be used.  Steer clear of softwoods like pine, fir, and spruce specifically, as they naturally have a tendency to spark.

With that said, there are more gas fire pit options than I can count available, particularly easily movable tabletop models that won’t spark and may not require a barrier due to design and the fact that they give off less heat. 

I won’t say they are the best options for decks specifically, but there are some attractive benefits to using gas fire pits in that location.  

You’ll ultimately have to decide what’s best for you knowing and implementing what we covered in this article.

Conclusion: Using a deck fire pit

With fire pits gaining in popularity, people want options on how and where they can use them.  With backyard decks being as expensive as they are, naturally, there is a fear of damaging your deck or worse when using fire pits of any type.

As we’ve covered, using a fire pit on decking can be done with minimal safety and cosmetic risk to the decking and the supporting structure if, along with your fire pit wants and needs, you take the time to explore the solutions and the gear mentioned, do a little research on local fire regs and locate your fire pit in the right spot.

For more, check out my article 3 Best Deck Fire Pits Battle for Our Top Pick for examples of wood-burning and gas fire pits that are well-suited for use on wood and composite decks.

Take care and thanks for reading! 

John

Related Questions

Can you put a fire pit under a pergola?  If you have a pergola over your deck, you can use a fire pit safely.  Gas fire pits are best in this situation from heat, smoke, soot, and spark perspective but wood-burning fire pits are still a safe option.  

Understand though, that discoloration of the pergola may occur with extended wood-burning fire pit use.  Also, the usual minimum height of a pergola is about 8 ft so ensure your fire pit fires don’t get to a point where flames pose an ignition risk.  If you have vines, fabric, lighting or any other kind of decoration on your pergola, consider placing your fire pit elsewhere or remove these items.

Can a fire pit be used on grass?  Yes, fire pits can be used on grass.  The heat-resistant barriers mentioned in this article can be used on grass as well as long as the surface is stable and level.  A light spray of water around the perimeter of the fire pit will minimize grass heat fatigue while using your fire pit and help it bounce back quicker afterward.

Please see my companion article on using fire pits on grass if you are looking to use other fire pit locations on your property as well.

Why is my fire pit smoking so much?  Nobody hates excessive fire pit smoke more than me.  If you have a conventional fire pit that’s not marketed as smokeless, like a Solo Stove or a Breeo, and you are continually dealing with a lot of smoke, there are a few things that could be wrong.  

The wood you use in your fire pit should be well-seasoned (meaning 25% or less moisture content – a.k.a. very dry) hardwoods like oak, hickory, white ash, black locust, etc.  Un-seasoned wet wood tends to smoke when burned.  

Also, steer clear of softwoods that have the words fir, cypress, spruce or pine in the name.  These softwoods typically have a high moisture and sap content, resulting in a tendency to smoke excessively when burned.

With that said, softwoods can be good for getting a fire going, but not as the main fuel source for a burn.  They can burn very hot for a short period of time and can be continually added until your seasoned hardwood logs get going.

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