The Problems with Composite Decking

By Scott Sidler • April 23, 2018

the problems with composite deckingThere 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 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 products and 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.

The 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. Below are some of the issues that crop up most often.


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.

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.

Warping & Shrinking

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.


This one has been the issue that I encounter most- composite decking boards that feel like a trampoline when you walk on them. They have gotten so spongey that they sag from one board to the next making your decking like a mini rollercoaster. I notice this issue showing up after a decade or more of use, but it certainly shows up and when it does it usually makes the deck unusable. 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, 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 2 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, 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. How about you?

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61 thoughts on “The Problems with Composite Decking”

  1. Yankee Lady and Foothill Family posted almost identical reviews (“Trex has a life of its own, and behave better when horizontal”) less than 12 hours apart. Someone is poisoning the well here.

  2. My trex deck is warping badly this season. It’s about twenty years old so I don’t know if I should have it ripped out and new deck put in

  3. Hello all who have posted here!
    I hear you frustrations and concerns and feel for you. If you could encourage someone in America to consider importing Millboard decking I can promise you you would not get the issues your talking about. Without sounding like I’m selling Millboard is made from resin rather than plastic and didn’t react to temperatures like plastic does. We have been importing to Australia and the Middle East for about 6/7 years now and though Millboard does get hotter than timber it’s not as hot as plastic, but the amazing thing about it is that it doesn’t move like plastic does, is expand Inthe heat and become soft or shrink in the cold and become brittle. It contains no protein based materials like wood flour/dust, rice husk, bamboo fibre to feed the growth of miss/algee or black mould and is totally non porous. This makes it genuinely low maintenance and in fact the more rain you get on it the better as it helps to wash it down. I would encourage you to look up
    I seriously feel sorry for you folks facing these issues as there is a solution.

    Kind Regards

  4. We had our deck replaced last July, and chose Trex Select. Since that time, the fascia board around the perimeter of the deck appears to have warped and the mitred corners have separated. The fascia board used along the sides of the stairway also seemed to twist.

    Our contractor has replaced the fascia boards along the side of the stairway about a week ago, and it already appears to be “rippling” in between the areas where fasteners are affixed. He plans on replacing the fascia board around the deck perimeter, but I am concerned that we will have a recurring problem. I am considering just having them replace the fascia with wood and keep the Trex on the deck flooring and steps. It seems as if Trex has a life of its own, and behave better when horizontal but does peculiar things when used in a vertical application. Any ideas?

  5. After a lot of thought, we replaced the old deck on our house last July. We decided on Trex after researching and noting that the previous problems were seemingly resolved. The deck flooring and steps were Trex Select, and the sides of the deck and stairway were Trex fascia board.

    Since then, the fascia board on the sides has bowed creating a large gap at the 45 degree mitered corners. The sun-exposed side of the stairway had bowed. Our contractor came out and has replaced the board on the side of the stairs, but within less than two weeks, it is buckling up in between the areas with fasteners! The contractor has suggested that more fasteners will fix the problem, but I sense that Trex has a life of its own and seems to behave when it is horizontal vs with vertical or oblique uses. Has this been noted? I am about ready to have them remove all the fascia board and just replace it with wood.

  6. Like Laurie, our experience with Trex has been good. I’m not sure what level of Trex we have – likely Select – but we’ve had it for about 10 years now. No problem with warping or fading. The deck was poorly built, without enough space between slats to drain water, so water collects on it and it gets dirty and mossy, but power-washing cleans it well.

  7. I am very confused now . I thought by going to composite , my problems would be over . My wife and I are also retired and trying to get away from the work involved with a deck We have already torn our old deck apart . It is a 20 x 24 deck to be done . Is there a wood that can be used that does not require a lot of staining and maintenance .
    Our deck get lots of sun for the better part of the morning . We live in Canada ,so are winter are harsh and our summer here are always filled with sunlight . So confused . HELP .

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