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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.

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192 thoughts on “7 Problems with Composite Decking


  2. Hi Scott,

    I need to redo a 3rd floor balcony deck on my townhome that currently has wood decking – it is 8 years old and is looking pretty ragged. Some of my neighbors have had issues with leaking and have had to do expensive repair/replacement projects. Our HOA gave specs that talk about replacing the membranes, repairing the boards, joists and scupper system, then cover with traditional decking (either wood or composite.) One contractor uses Duradek vinyl system, which is a completely different take on the project. Do you have any advice on whether this would be a good way to go? Thanks!

  3. My parents had their deck rebuild by a contractor that sold them on composite decking. I want to find that contractor and beat them with the scraps they stole from the project (over 100 square feet I was planning to use to floor a shed), because their deck bends when you walk on it, is impossible to clean (I have a cedar deck at home, which I pressure wash and timber oil every year, it’s a 5 hour maintenance project plus the “don’t walk on it” time, and the simple green and pressure wash method does NOT work on their composite deck, it requires a harsh cleaner to get the pollen out of the textured surface.) AND IT GETS HOTTER IN THE SUN! Why? It’s PLASTIC! Not going to lie, I used to live in shipping containers with no electricity and well water. I put 250 feet of garden hose on top of one container, snaked back and forth, and had it hooked up to a 1.5 GPM shower head over some bamboo slats, and I could take a 20 minute hot shower. Plastic gets HOT. Yes, my cedar deck is uncomfortable sometimes, but that’s at 5 PM after it’s been in the sun for 8 hours. Theirs is hot at noon, and it’s on a west side of the house. I would NEVER recommend this inferior product, you’d be better off building your deck with stud lumber. For the same price, you could replace it every 5 years.

    1. Most likely the contractor gave a bid for a deck to your parents. if he delivered the deck as specified, any leftover pieces belong to him as they were not part of the deck.

  4. A few thoughts:

    The deck surface is only as good as the frame underneath. Sadly, ours rotted in six years, even though I followed all maintenance instructions. Now I know…
    * ensure the right joist hardware is used, correctly installed and properly flashed.

    * Ensure a quality protective tape is properly applied to all top surfaces, and also to any vertical surface that will have another board (eg fascia). I *love* G-tape (3040BK,currently cheapest at gtapeusa)… Can tear it, and it does not stick to itself… Rather nice when working with a foot wide roll!

    For lack of 250 bucks of gtape, ours would not have rotted.

    * I am happy with our composite. Watershield even works underwater! The composite is fine… The joists, not so much.

    * I am SO happy to be done with wooden decks. Had gorgeous cedar, in the CO mtns. Absolute pain to keep up with maintenance.

  5. I replaced my decking in 2013 and when I went back to HD for another project adjacent to my deck the product I started with was discontinued and removed from all stores. As time went by , 3 years, my decking started to crack, HD could not figure out who made it for this area so I spent a few years tracking this down. I did learn that there was a class action law suit related to this cracking in the west. After a few years of emails with replies stating not our product I found it was from deckorators but they would not warrant it without receipts and would not take my dated photos with my property ownership for 15 years. The finally sent someone to inspect after months of waiting three people showed up, mfg rep and 2 from HD. After a few weeks I got a letter saying it wasn’t installed properly on 16” centers but the damage was in an area that was 12” centers. My opinion HD removed the product because of the cracking and law suite and Deckorators would not admit that this product was inferior and replace it. What I learned is that HD buys from multiple vendors and the product is mfg all over the country and you don’t know what you are going to get. A good point wood is wood, composite is whatever HD wants to sell regardless of color or quality. I have photos over time as this product started to fail.

  6. Hi Scott, have you heard of the decking store? If so do you know anything about their composite decking. Its quite a large area we re decking and do not want to make any expensive mistakes? We are back and fourth about whether to go for wood which is what we had previously or composite decking.

  7. Hey everyone,
    I’m a new homeowner and just had a new timber tech deck installed (pro series).
    I was wondering: will we get swelling deck boards if we don’t put some sort of sealing on the cut ends of the boards?…or am I over thinking things? Our installer (silver TT rated) said we should be okay, but i was curious if we should just cap things ourselves after they’re done.


  8. Ipe wood is bug proof,rot proof, and has a class A fire rating like steel and concrete. It also lasts forever. Who thought “plastic” was a smart choice for a one time install?

  9. We are looking to install Duralife composite deck 400 sq. ft. I’m in Canada, east coast the weather gets quiet cold in winters. Any comments or suggestions.

  10. We (my wife and I) purchased our current home, as new, nearly 18 years ago. It came with a deck that was made with early type (uncapped?) composite decking. The spindles and posts were also made of the same material. The home builder was so impressed by the product (at that time) he wished that he had used it for the large deck, he had recently built, on his own home. I was excited about having something touted as being “maintenance free.” Over the years I have power washed it to keep the vegetation (moss? algae?) at bay. Mind you, I was never really told how to maintain it (or that power washing was possibly bad for it). For the most part it has held up well and we have enjoyed the deck.

    This spring, as I was looking around it, I noticed some sagging. The railings are showing signs of fatigue as well. For 18 years, I would say it has served us well but, not really knowing how long it was supposed to last, makes it difficult to assess if we really got our money’s worth? I would like to think we have but just not sure.

    At this juncture, we’re considering replacing the deck with a 3-seasons room and just utilize the concrete patio, next to it, when we want to be outdoors.

  11. I read this because during the past three years my composite deck boards have swelled and warped to the point they are affecting the vinyl fencing around the deck, to say nothing of the risk of tripping when I walk on it. When I purchased the house over five years ago, it looked great, with enough space between the boards for water to go through. I am trying to figure out if there’s anything to be done besides having the entire thing replaced! Could just cover with a thick carpet, but I may sell next spring, and want to get it resolved. Any advice welcome!
    Looks like the 25-year warranty was only good for original owner – looking into that, but I doubt it will do any good.

  12. I’m surprised by a lot of these comments. Most of these products are not very well performing. Azek is OK. They actually got in a lot of trouble and settled a major lawsuit just a couple years ago for marketing their product as PVC. It’s not a true PVC deck product and many customers had issues around 10-15 years. So they created their own term called Armor Alloy Technology. It is NOT a true PVC product. Many people in these comments are wrong and spreading false information.

    Cellular PVC decking with an ASA capstock is the best decking in the entire vinyl deck industry. Vekadeck is the best vinyl deck board in the entire industry. Veka invented Cellular PVC decking years ago, and in recent years they’ve beefed it up and added an ASA (acrylic) capstock to it to further help resist fading.
    You cannot go to any lumber yard or store and order Veka. It’s only available to the biggest and best deck companies in the country. Veka comes to you, you don’t go to them. I assume no one in the form has to ability to buy Vekadeck or else I’d see it mentioned. There’s probably 1-2 companies per state that can carry it. In NY there’s only 1 I believe, Upstate. Vekadeck has the most intense Wood grain texture out of any deck board. Nothing compares to it in the entire market. I wish it was more widely available but Veka is a super picky company about who they’ll let install their products.

    Wolf PVC decking is very good too. It’s 100 percent PVC and it’s equipped with an ASA capstock as well. It’s not as good as Vekadeck. Even though it’s the PVC and ASA, it’s what’s in the mix of the product. All vinyl is not created equal! They have a nice wood grain texture but not as pronounced but still nice. They have a lot of super nice colors. It’s a good board, I’d place it up there in like the top 3 you can buy.

    There’s a couple others out there. There was a product called Clubhouse decking that was awesome. They ended up getting bought out to a company in Canada and downsized a lot. Just didn’t have enough funding to keep up.

    Fiberon, trex, Timbertech composites are all horrible. Don’t be fooled by the contractors on here saying it’s not what it used to be. It is. They rebrand their boards every other year. They have good better and bests. New names every year and ground breaking technology every year. It’s a bunch of crap. They’re cheap and don’t last. Inside is wood fillers and recycled milk jugs, garbage bags etc. outside is a cheap “vinyl” capstock. It rots from the inside out. Read between the lines of the warranty too. It won’t cover any of it due to weather conditions. These are the only products most contractors can get so of course they’re going to say they’re good.

    Only wholesale big box store product that is even somewhat decent and at least better than any of the others, is Timbertech Azek. It’s not a true PVC deck board however it is Vinyl. They call it Armor Allow Technology.. whatever that means. Check their lawsuit 3 years ago.

    Do your research to anyone who’s reading and I hope this helps. Please don’t make an expensive mistake and listen to the contractor whos limited to these composite products.

    1. Thank you, vinyldeckguy. We are in the process of replacing our 25 year old wood deck with pvc.. We are still researching the different products but are leaning to Azek.. We would prefer the Veka you recommend if we can purchase it… Your in depth of knowledge has been the most honest opinion I have read… Thank you. Mike and Lorie

  13. The key to success is to use the proper product for what you are trying to do. The big box stores sell mid level products — “it’s the best we sell” . Has no relevance to the overall market.

    What may work on a properly built deck in a dry area — may not at the beach (hot) or on a ground level deck in a moist area. They are not universal products … some of the composite products will not work with typical 16″ spacing when replacing a wood deck — especially one that’s not firm to begin with. If you are doing a composite — read the specifications and installation instructions.

    I’m in the mid-atlantic and have replaced both of my decks — beach and suburbs – with Zuri. It’s expensive. Both at one time were cedar — over PT frame. Even buying the best cedar and finishing both sides — 10 years it was a mess. I tried the better PT decking boards — ugly. I took off the PT after 4 years and put down the Zuri … down about 5 years now. It’s strong enough to span the 16″ on a very solid structure.

    Alternative to wood building products have a place .. I’m restoring and adding to an old stone building in PA …. in a damp area they can be the best option ….. also, if fire is a concern.

    Pick carefully … people think they are a cheaper way to go … this is not always the case.

    1. You mention not being able to install on 16″ centers, but that’s what the composite brand I have seen calls for, and it bends under a human being’s weight, up to about 3/4 inch. Maybe I’m crazy, but my deck I engineered is on 24″ 2×6 centers, supported in 13 places over 260 square feet) with 2×6 cedar and it does not bow, squeak, flex, or otherwise bother me. The deck in question is in a damp area (Pacific NW in a temperate rain forest) and is impossible to clean off in the spring from the winter season without harsh cleaners. I can clean my cedar with a 15 degree pressure washer nozzle, some simple green, and seal it every year with natural oils and it’s lasted over 5 years with no problems.

  14. Holy smokes…this article is full of misinformation. If this was written 12 years ago, some points would be valid. Otherwise this is very misleading and straight up false on most points with any decent brand. The picture you posted with it is low quality, Chinese imported junk.

    If the article was to say there are a lot of cheap, garbage composites out there…I would agree. But there’s also a lot of high quality options that don’t do the things you say. Then there are PVC options and inorganic composite options like Deckorators that simply outperform everything. But to paint the whole category as bad is absolutely false. There are bad brands of products in every building material category…doesn’t mean the whole category is junk.

    1. Certainly doesn’t mean the whole category is junk, but trying to discern which company is making the good products is difficult since they all claim to be making quality, lasting composite decking. If you’ve founds some winners here then share them with us. For me, I’m not comfortable trusting the same companies who told us 20 years ago that their product was foolproof and failed that now they’ve REALLY made it foolproof. Fool me once, shame on you, fool me twice, shame on me.

      1. Have you ever dealt with Weardeck? I have to span 24 inch centers on my deck and they seem to be the only company that will certify a 120 per square foot at that span. It is a fiberglass composite but I cannot find much information on them.

        1. I have not used Weardeck. 24″ O.C. is tough for decks because it really does limit your options and often results in more spring/sag as time goes on.

          1. What is your opinion of the fiberglass decking in general. I am planning on running extra joists to make it 12 OC but a few bolts will require me to tweak two or three I have to add in. I don’t think that an inch or two either way will make any structural difference. Joists are 2x10x13’.

        2. Add extra joist to achieve 12″ centers. You can always go above and beyond code. Never settle for bare minimum.

  15. I am looking at replacing my 10 x 16 wood deck with Fiberon Concordia in a shade called Cinnabar. What can you tell me about this product……pros and cons?

  16. I am so happy to have read about this topic: Composite decking. I have an enormous, old, pressure treated wood deck and have been thinking to myself for years now that if only I could afford one of those no maintenance newfangled decks. There is actually nothing wrong with my current deck, it’s as strong as ever, even after 36 years! I think I will keep it, for now.

  17. I am an retiring lady looking to redo the wood surface of my 24×16 deck in Miami with Fiberon Goodlife weekender composite decking boards. I need a good looking low maintenance and durable surface. Is this a good choice?? How do I know if a contractor is knowledgeable?? Please help!

  18. Aluminum decking! Yep, it’s a thing, and it’s completely awesome!
    So glad we went with it instead of bothering with composite. Wahoo Decks has great products and have always been a pleasure to work with.

    1. I went the same way, extruded aluminum and removed my TREX. There was nothing wrong with the Trex but it was not properly shielding the area below the deck from water penetration. I installed Nexan decking designed for resistance to penetration and found that I removed over 1,000 lbs from the weight of the deck, found that it was actually cooler to walk on, and was able to hold less than 1/8″ width variation over a 16′ span. Yes, it’s can be scratched with something that scratches but there is a touch-up kit that quickly repairs the surface.

  19. I bought a remodeled house which the builder put composite decking. I’ve talked to lots of distributors and nobody knows what brand it is. The problem I’m having is it turns moldy constantly it’s cracking and it flakes off in strange circular type patterns. What can I do? Can it be painted over with an epoxy or something to save it?

    1. When did you purchase the home and was the deck recently done. If there is mold, you will have a problem with virtually all warranties. I had a 500 plus sq foot deck under construction and the delivered boards from TimberTech had mold, irregular finish plus the finish was flaking off where the pattern was irregular. The rep refused to come on site. I returned all the uncut boards to the lumber yard for credit. There are serious inherent design problems with the composite decking product. Buyer beware. I am in the process of switching over to aluminum boards which are more expensive. As my father used to say, quality remains long after the price is forgotten. rsteen1@msn.com

  20. Hi Scott, we are getting bids from local home improvement contractors on building a 14 x 16’ deck. Are you familiar with Wolf Serenity deck boards? Do you know how the quality would compare with Trex? Trex seems to be much more expensive. Thanks for your opinion.

    1. Don’t buy it. I only had mine for six years and the boards have warped. My deck is ugly now and no one is helping me be compensated for this crap decking. No joke!

      1. Are you sure you mean wolf? Wolf is a PVC product with an ASA capstock. It’s one of the best PVC deck boards available and it doesn’t rot, mold, mildew or warp. Are you talking about trex in this?

        Carol.. wolf is a very good product. I’m actually surprised you got quotes with trex being more expensive. Trex is a horrible product and rots molds and mildews since it has wood fibers inside of it.

        VEKADECK is the best deck board in the entire vinyl decking industry. It’s very difficult to get and they only offer their products to the top decking companies in the country. If you can find that, it’s your best option.

        Wolf decking is probably top 3. It’s a very good deck board.

    2. Carol.. wolf is a very good product. I’m actually surprised you got quotes with trex being more expensive. Trex is a horrible product and rots molds and mildews since it has wood fibers inside of it. Look up consumer affairs and read all the horrible reviews about trex.

      VEKADECK is the best deck board in the entire vinyl decking industry. It’s very difficult to get and they only offer their products to the top decking companies in the country. If you can find that, it’s your best option.

      Wolf decking is probably top 3. It’s a very good deck board.

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