fbpx bloglovinBloglovin iconCombined ShapeCreated with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. rssRSS iconsoundcloudSoundCloud iconFill 1Created with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. Fill 1Created with Sketch. SearchCreated with Lunacy Search iconCreated with Sketch.

7 Problems with Composite Decking

The Problems with Composite Decking

Since I first wrote about the problems with composite decking in 2018 there have been a lot of comments and questions especially recently asking me to update the info and if any of these issues were still true. So, I have fully updated the information with references to new products on the market and changes here in mid-2024. I only hope it helps people make an informed decision.

There are a lot of options for decking today. It’s not like the old days where you had to simply choose between different species of wood. Today, you have all of the wood options of yesterday, but now there are scores of different composite decking options.

If you been a reader of my blog for any amount of time, you’re probably thinking “Oh now, here he goes again bemoaning another modern product.” Well, I want to tell you that that is not the case. I don’t have problems with new products, only subpar ones.

Sadly, most composite decking falls into that category. It has been improving slowly over the years with the introduction of capped decking, and technologies like CoolDeck among other upgrades, but still, the reports from consumers and contractors are not promising. Take a look at some of the websites where homeowners have posted their reviews, and you’ll read 1 and 2 star reviews all day long.

7 Problems With Composite Decking

There are a multitude of problems with composite decking that show up all too often to be just a stray issue for a hard to please homeowner. The accounts of issues are repeated with a frightening regularity and sameness throughout the threads of complaints.

Many homeowners acknowledge the issues, but still prefer the composite decking to traditional wood decks, usually due to the maintenance required for wood decks. Below are some of the issues that crop up most often.

1. Composite Decking is Slippery

In the last few years Trex and Deckorators have release “slip-resistant” versions of their composite decking, and while these are better than the older composite decks they are still far more slippery than a wood deck.

When you put water on top of plastic it is always slippery since it cannot absorb the water like a wood deck can. It’s a just a fact of life that composite decks are still going to be more slippery than wood decks.

There are aftermarket non-slip coatings you can apply to your composite deck. I can’t speak to the effectiveness of these coatings since I haven’t used them myself, but I know they are out there if you are wanting to experiment and find a potential solution to your slippery composite deck.

2. Hotter Than Wood

Composite deck manufacturers have been working on this issue for decades with very little improvement other than marketing spins. Today you’ll find CoolDeck technology from MoistureShield and Transcend Lineage by Trex which “is engineered with heat-mitigating technology to give you our coolest decking yet.*” I had to search for where that asterisk was referenced and here was the answer from their page:

*Although Trex Transcend Lineage is designed to be cooler than most other composite decking products of a similar color, on a hot sunny day, it will get hot. On hot days, care should be taken to avoid extended contact between exposed skin and the deck surface, especially with young children and those with special needs.

If you live in a northern climate this might not be an issue for you, but anywhere in the southern US and you likely will suffer from this issue. It’s not just the issue of being hot on bare feet but also the heat that will be radiating from this deck while you sit on it. Summer is hot enough without a deck radiating a ton of heat back at you.

If you still insist on composite decking then choosing white or light grey colors will keep the deck surface cooler, not as cool as wood but slightly lower than the surface of the sun.

3. Tighter Joist Spacing

If you are planning to simply replace your existing wood decking with composite decking you need to be sure that the supporting structure of your deck is sufficient. For wood decks covered with 2×6 or 2×8 boards 24” O.C. joists are not uncommon. Most wood decks using 5/4” decking will require 16” O.C. joists. Composite decking can be different though.

Dan Gileo of Decks & Docks has been working in the decking industry for over 25 years and his recommendation is a minimum of 16” O.C. joist spacing for straight installations, whereas 12” O.C. would be required for diagonal installations to avoid sagging.

Composite decking varies by manufacturer and even though it may be fine for several years at the wider spacing, many installations I have come across begin to sag even with 16” O.C. spacing after the 10-12 year mark. So I would recommend sticking with the 12” O.C. to be safe.

Also, many composite decking materials require 12″ or even 9″ on center stair stringers spacing to support composite stair treads.

The point is make sure you account for the added time and costs of reframing the support structure if you are changing from wood to composite.

4. Mold & Staining

moldy deck boards
Moldy deck boards

Especially prevalent on older and uncapped composited decking, mold shows up quickly and is more difficult to eradicate than you’d expect. The mold seems to grow heavily not just on the surface, but inside the rough texture of uncapped decking. It seems to come on strong and takes constant effort to keep the decking clear of it, especially for a self-proclaimed “no maintenance” product.

Even with the recent technology improvements mold and algae still shows up quicker than I would expect. Staining is another problem with composite decking. Depending on the landscaping even things as simple as the tannins in fall leaves or berries can permanently stain these composite deck boards so be sure you don’t have issues in your location.

5. Color Fading

Everybody knows color fades in the sun, but composite decking companies seem to be oblivious to what their products are really capable of. Some composite decking has faded so quickly in just a couple of seasons that replacements boards stand out like a sore thumb. Just like the mold, this issue is unpredictable and hard to understand which decking will have problems and which will not.

Trex currently offers a 50-year warranty on their top line decking, but it’s hard to imagine the deck will be anywhere near the same color it was when originally installed. And unlike wood decks where colors can change over the years as you stain them the options for changing the colors on a composite deck are extremely limited.

6. Warping & Shrinking

warped composite decking
Severely warped composite decking

It’s not wood, so it shouldn’t be expanding and moving the same, right? Right! It actually moves more AND more unexpectedly than wood decks. Some composite decking won’t move a bit and others have been found to shrink, swell, warp, twist, bow, and any other word you want to use in amounts unheard of, even with wood.

Again, it seems completely random when this happens, but it happens often enough that you should know about it. The best explanation is that plastics have greater movement than wood and as materials heat up they expand more. So, with a composite deck that is largely made of plastics and gets hotter than wood decks the movement can be extreme.

7. Sagging Boards

Even if you use the proper spacing composite deck boards are notorious for sagging. Especially the lower end products. The top of the line products have done an excellent job at preventing this today, but there is still enough sagging in the best boards that it makes me uncomfortable using them.

I notice this issue showing up after a decade or more of use, and when it does it usually makes the deck unusable. On my own house I have a composite deck that is 21-years old at this point and the sagging is extraordinary to the point we can’t really use the deck until I have the chance to replace it. Check out the video below to see how springy these boards can really get!

What To Do?

For now, I’d say the best way to avoid problems with composite decking are to avoid it altogether and stick with wood. You may be one of the lucky ones who installs composite decking and gets away with it, or you may end up constantly on the phone trying to persuade them into the honoring their warranty, which is extremely hard to do.

Sure, wood has issues of its own and requires staining occasionally (here’s a great tutorial on staining wood decks) but it’s nothing that will take me by surprise. And if it needs a replacement piece, it’s as easy as swinging by the local lumber yard rather than trying to track down a model that has been discontinued five years ago from a supplier halfway across the country. As for me, I’m sticking with wood. How about you?

Composite decking has come a long way since it first came out, but it’s not there yet. Someday, the industry may be able to create a consistent long-lasting product that lives up to the claims and avoid the problems with composite decking currently, but right now, they can’t seem to make it work. When they can make a product that is consistently better than wood, then I’ll be in line for it, but until then I’m sticking with a reliable option like wood.

If you’re looking for a reliable wood option that has little to no maintenance and can easily last longer than composite decking I would encourage you to check out Accoya. It is not the same as traditional treated lumber and is perfect for a deck even in the toughest elements.

Subscribe Now For Your FREE eBook!

192 thoughts on “7 Problems with Composite Decking

  1. Has anyone had experience with NewTechWood on a deck? Plan on installing 800 sq. feet deck in the Dallas, Tex. Area.

  2. Does anyone have experience with TimberTech AZEK Vintage Collection or TimberTech Pro Legacy being used in desert/extreme heat/high sun areas?

    1. Many contractors use this from the forums I’ve seen. I’m looking at Fibero , however. They have a few “best” brands, and I’m considering their Concordia Symmetry line. Do not buy Trex! Do not buy anything w a 10 yr warranty. These aren’t cheap but we are doing them ourselves and using out own hardware. If you find Aztech for a good deal, snag it, but Fiberon seems to be the go to now. Good luck.

    2. This is a late reply but we built our deck using the Azek line. The product was faulty from the start but they’ve been trying to blame it on the installers. The installers thought the scratches and scuffs they saw were minor and the boards were so filthy, they figured washing it off would take care of it since this was sold to us as being “premium, high quality” product. Buyer beware. This product scratches easily and we rubbed two boards against each other after install – instant marks and they still claim it’s scratch resistant and the best product. It’s not.

  3. I’m replacing a 24 x 18 ft elevated deck (12 ft ) that has 16 inch joists. I would like to use the Azek PVC product, but cannot afford to redo the joists to 12 inches to avoid a spongy surface which I have previously experienced. My wife loves the deep wood grain pattern of the Envision Inspiration Collection which would provide a firmer surface, but it is only 3/4 capped and does not have a fade or stain warranty. I have previous experience with TimberTech (TT) replacing 2 decks under warranty. Their Pro Legacy and Reserve Collection is fully caped with the new Reserve surface having a slightly deeper pattern. Considering the requirements listed above: 1) does the Envision Inspiration product’s unique process and 3/4 capping provide a strong board that will not flare, 2) wouldn’t the TT top 2 collections be a safer choice considering the more specific call out of the warranty, or 3) do you have some other recommendations.

  4. Deckorators Decking boards use a sapped polypropylene/calcium carbonate core making it pretty much water proof. It’s got minimal expansion and contraction and is basically bulletproof stuff. Recommended
    Dave Fraser is correct in saying that a lot of the composite boards on the market have improved remarkably over the last few years. The thing letting a lot of them down is the installation. They do have their idiosyncrasies and if you don’t know what they are it can make or break your decks future. Expansion/contraction is the main one and the need to cut the boards lengths to compensate for the ambient temperature of the boards. Hard to understand for the average builder or DIY weekend builder.
    Get a dedicated decking company or builder to build your deck!!!!!! This will save you issues in the long run

    1. I used Trex Transcend to replace old treated boards which had lots of weakened spots from essentially cracking and falling apart. I used the old 16″ center joists, covered the joist tops before installing and left all the proper gaps, used trex hidden fasteners too. This will be third year, love the deck, no fading and looks as good as the day I installed. Only issue I found was the boards sag between the last 2 joists at the end of the board so I am going to go under and add a joist between the joists so it’ll be 8″ centers at the end of all trex boards. Otherwise, extremely pleased in NE West Virginia.

      1. Sic years down the road it will no longer look nice. The boards sag and twist. My deck is so ugly now and they do not back their product up at all.

  5. I used an professional deck contractor to build a 24′ x 16″deck using Menards best composite decking. The very first rain after it was completed, I found that nearly every length of decking would retain the rain water for several days until it would evaporate. I called Menards who put so many costly conditions for replacement by them, I am looking for alternatives to avoid the water retention. I am afraid that the deck as it presently is, will prematurely decay without some intervention.

    1. I hate to be frank but Menards highest end decking is probably still average if not less than average at best. There is an entire line of very very low end composite decking that you can buy in the range of $2 -$2.50 a square foot. I can assure that level of composite decking actually may be worse than wood itself. I say that with some sarcasm but what you are experiencing doesn’t sound like there best composite. Maybe it was the best they stocked. What you have though is a loose grain composite core which actually is like a sponge. It will soak up the water and retain it until the board is warm of enough for it to evaporate from.

      You may be able to seal that composite core, yes I mean with an oil based preservative like TWP or something like that. Some decking providers will even indicate that sealing is ok. If you can’t find it directly written anywhere on the product you could try calling the manufacturer, not menards. Otherwise get a sample piece and just try it. That might give you some peace of mind for a little while.

      Replacing the product may be the only other option if sealing doesn’t work.


    2. Hate to hear it, but Menards sucks. Might as well be associated with harbor freight. The items inside will get you by, but they will not last.
      Sounds like your decking had the “brake light” warranty!
      Good luck. Wait for a good dry spell and seal it. Cheapest option now.

  6. Eric

    I would not use a composite capped product near that much water. The core is made of a polymer, plastic wood and other stuff that by nature will swell if exposed to regular moisture. AZEK not Timbertech and other companies make a solid PVC product that will weather far better. In fact it should be nearly impervious to water as it is PVC. Lowes can special order AZEK they now have a display of their material at our stores here in KC. If not check with your local lumber yard they normally carry it. I can help find you a distributor in your area if you want to email me your info at kcweekendwarriors@gmail.com also more than happy to speak with you on phone if you need some help. Just send me a number you can be reached at in the same email.



    1. thanks a bunch for your reply and advice – I greatly appreciate it! I’ll definitely look into the PVC decking that you suggest!

    2. I have a question(s) you might know the answer to. I’ve researched this more than I care to admit because I knew nothing. And knowing our family I don’t see us sealing wood once a yr.
      Pure PVC seems like it’s great for areas around pools and is not slippery too. Is that correct? I live in Southern CA. Need it to replace an upper balcony. I probably wouldn’t need this, though being that it’ll be dryer here, would I?
      Also, I hadn’t considered needing it capped, as it will have room to breathe. Am I mistaken? Plus, it is so well seamed, waterproofed, ect., it’s crazy. Dunno if this is relevant to this, but Holy cow!!!! This is because it’s part roof over our breakfast room.
      Also, do you know, by chance, if all of the prices are going to be the same per specific item? I found one lumberyard advertising 7% cash back on purchases. This stuff is expensive, but a good investment. I’d like Fiberon Concordia-Symmetry Line. Does anybody here know if prices vary at all? We’ve spent an embarrassing amount on getting it ready to put the floor on! Oh, I forgot, I meant to ask if you knew wheter PVC scratches more easily than Composite?I’ve watched a million comparison video’s. Dunno if I saw this but I will look it up in the mean time. Aluminum I fear will easily dent…
      Sorry for so many questions, but thank you.

  7. Mr. Becker,
    I am considering composite for decking my dock on the lake here in Central Alabama – lots of sun, and a good bit of rain. I like what i read about Veranda Capped Decking Composite Decking Board, available through our local Home Depot. Have you had experience with this product – I would greatly appreciate your thoughts on this.

    1. Eric, I didn’t see your comment here. Did we speak over my email? If not I would not used a capped product near a dock. It’s core is still susceptible to swell especially in an environment where it might be constantly wet. I would shop solid PVC decking. Any brand would work if it were solid PVC, we are just experienced with the AZEK material which I know is quite good. Let me know how else I can help.


      1. Adam, you sent me some excellent info earlier, I may have been remiss in thanking you:

        Adam Becker commented on The Problems with Composite Decking.
        There are a lot of options for decking today. It’s not like the old days where you had to simply choose between different species of wood. Today, there are still all of the wood options of yesterday, but now there are scores of different composite decking options. If you been a reader of my blog […]
        Eric I would not use a composite capped product near that much water. The core is made of a polymer, plastic wood and other stuff that by nature will swell if exposed to regular moisture. AZEK not Timbertech and other companies make a solid PVC product that will weather far better. In fact it should be nearly impervious to water as it is PVC. Lowes can special order AZEK they now have a display of their material at our stores here in KC. If not check with your local lumber yard they normally carry it. I can help find you a distributor in your area if you want to email me your info at kcweekendwarriors@gmail.com also more than happy to speak with you on phone if you need some help. Just send me a number you can be reached at in the same email.

  8. Curious if anyone has installed the Timbertech tongue and groove porch boards. We have an enclosed porch, not heated or cooled, that we’re considering putting it in.

    1. Beautiful product and the end result really does look good. Anxious to hear if you did or are still looking at options.

  9. I’m having a new house built and it’ll have a rectangular 12’x32′ deck, so I’d really not want to have to seal & stain that every year or two. Composite is the only way I’m willing to go, for that reason. All that said, if choosing between MoistureShield, Fiberon, Trex & Azek, what one would you recommend? Some say they get a third less hot than regular composite, some say they’re less slippery…
    I’m probably over-worrying, but we’re retiring in the Pacific Northwest, so I worry about it being slippery when wet, too hot in the sun, moldy in the winter, not durable enough & all that jazz. When I’m on my pension I don’t want to be replacing expensive composite then. Do I just spin the wheel & pick whatever company’s most expensive product line?
    Thanks for any advice you can give.

  10. I’m always skeptical about new materials. I try each one under average conditions. The composite stuff has performed well under most conditions. My disclaimer however is to stick with wood don’t kid yourself on the maintenance. Wood takes some, as does the composite.
    Maintained properly, wood will last longer. Never stain! Never paint! (Pressure treated). Use a sealer like Thompson’s or other. When you need to re-apply, never pressure wash! Just lightly sand and re apply. PRESSURE WASHING WILL RUIN A PRESSURE TREATED DECK! And, one final thing. Always maintain adequate ventilation under the framing. That’s critical.

  11. My Fiberon deck is a couple years old. It has warped between each joist ( 16″ ). Also the mitered corners are spreading ( shrinking).
    The builder refuses to address this. How do I address this with Fiberon? 2years and it is a mess. I spent too much to put up with that.

    1. wait, what? oh no? May I ask which line you used? That’s the line we are considering buying? The line we are considering has like a 50 year warranty though.

  12. Living in mtn town, Prescott AZ. Rain, snow and lots of sun throughout the year. Would you recommend composite or PVC decking for 2nd story deck?

  13. I am a high end deck builder in San Diego, CA (Fraser Decks And Patio Covers). What he is saying about composite decking used to be true, but it is no longer remotely accurate. Azek decking, TimberTech decking, and Trex decking have solved most of these issues. 8-10 years ago fading was a major problem, but the newer, higher end boards do not fade much (it’s literally part of their warranties). Mold is not an issue with Azek decking as the product is all PVC. TimberTech and Trex can have this issue if not installed correctly, but it is extremely rare. The major issue with composite decking is contractors not knowing the products and not understanding how to install them properly. If installed correctly you should have a maintenance free deck for 25-30 years. Also, if you use a reputable installer they will have a labor and material warranty through the manufacturers…so if something does go wrong you pay nothing out of pocket. Deck building has become a niche specialty because the details matter so much if you want a long lasting, quality deck. I advise you to only use an actual deck builder and not just a general contractor who says he can install decks. If your installer is not a Gold or Platinum rated installer by the manufacturer you should hire someone else. Almost all problems with composite decking are due to installer error.

    1. I said this earlier in my comment, get a proper deck builder to build your deck, the guys who build with composites will steer you in the right direction with what to use and they’ll do a top job of laying it.

    2. Have you had any experience with the ends of Trex Enhanced boards curling up? We just picked up all new boards and have a picture frame around the outside but the vertical boards curl up at the ends and are not level with the picture frame board.

  14. Adam, What kind of railing do you use when you install a second story deck with Azek? Also, is there a specific name for the high end Azek you mentioned? Any tips regarding the limitations of Azek’s limited warranty that your customers may have concerns about?

    1. We would use Fortress metal railing posts and inserts in that 2nd story situation. You could still use a wooden post if you wanted to it just needs to be secured properly with screws and blocking so it doesn’t wiggle loose. The vintage collection is AZEKS high end. What you are buying is the appearance, the high end product is made with the same material as the low end. All three come with a 50 year warranty.

      We have not had a call back for any of AZEK decks. The biggest concern would be staining by natural elements, that is not covered under the warranty. It’s only a surface stain and trying to remove it right away may not work. For me it comes right off if it sits there through a few rain storms.

  15. I live in an old (1905) house in Iowa with a large wrap around porch. Part of the porch needs to be replaced and we are trying to find a composite porch floor (not decking). I’d like to get away from the paint maintenance. I can’t seem to find any customer feedback on the products available. We are considering Deckorators Porch Flooring. Information from seller is it has only been installed at one house within the last month. Installer said it installed fine, but I’m not so worried about the install, but lifetime performance. It will be a substantial expense, so I would like to find the right product. Have you seen the performance of Deckorators? Any other ideas?

  16. I think this author minimizes the upkeep required with wood decks. I just had a fairly old cedar deck replaced with a good composite and I am thrilled with it. Over the past 5-6 years, the cedar deck required ever increasing maintenance and attention and was starting to rot in places. Even with the replacement of boards, it never really looked good. Every summer it also required treatments to keep carpenter bees away. I loved that deck when first installed, but good riddance.

  17. I am a high end deck builder in the KC Metro Area, KCWeekendWarriors you can look at our facebook page or website. This blog is a perfect example of how social media can destroy the reputation of a product or company. While there are many differences with composite decking some can be mitigated with proper installation and others are just how that product responds to weather. In most of the circumstances we come across with clients wanting to fix or replace composite decking they had installed more than not it wasn’t installed right. That doesn’t fix some of the design issues with products like Fiberon which only caps the top and sides of the board and before they cut the groove. This defeats the purpose of cap and will cause the board to swell over time. Doesn’t mean they make a bad product you just need to be aware of what will happen. If you are not comfortable with what you know or have been told about a product you are interested in I implore you to find someone who knows what they are talking about, who has experience with the products and years of installation. High end composite is not cheap but it responds well and can be backed by reputable companies. Do your research, Azek for example has a 50 year warranty on their decking but you need to know what it the warranties cover. More than happy to answer questions anyone has.

    1. We are building a ramp for elderly and handicap accessibility to the beach on the Florida east coast. It will slope and have three flat spaces as the ramp slopes down. Do you have a recommendation for what material we should and should not use?

    2. I am getting ready to re-deck my 15 yr old wood deck in the KC area. I have a contractor already lined up. I’ve already purchased Fiberon Sanctuary decking mistakenly believing almost any composite decking was superior to wood. Can you advise concerning any experience/knowledge you may have about that particular product or installation issues? Admittedly, its a little late to find out now, but I’d like to know what to expect. Thank you.

  18. I am a deck builder in Kansas City and previously in Va been doing it for 30 years. I’ve seen them all come and go. We primarily use high end Azek and haven’t had a single call back for any deck we have built. No problems with it. It’s not cheap at about 12 a square foot but it’s obviously better than many of the other products mentioned here.

    Envision is a low end product at a high price. It will fade stain and mold dont care what anyone says.

    More than happy to answer questions about many products if anyone wants to know more.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.