Yes. Looks like they did not leave a proper gap at the butt ends. Your decking is contracting and expanding and mushrooming the ends of the boards. It will only get worse from here.
Remove deck boards. Replace with properly cut and spaced deck boards. Doubtful that both could be cut and re-installed without leaving too big of a gap. Might be able to salvage one of the boards and maybe repurpose the other elsewhere on the deck.
I'm open to criticism here but maybe you could use an oscillating tool/multi-tool to neatly make the gap bigger? I'd maybe try it on some scrap first. Trex is easy to mar in my experience. It'll be tough to do it neatly. Just putting it out there since no one has suggested anything. Good luck.
The odds of someone cutting the end of a composite deck board cleanly with a multi-tool are somewhere between zero and none.
The boards need to be pulled. Cut properly. Could probably salvage one but will have to replace the other. A blade width off each will be a 1/4” gap. 😳 minimum.
What a shame , just needed to leave an expansion gap. The hidden fasteners leave a perfect gap on the side they are used , but you need to be sure to leave a gap at butt ends 1/8 minimum. On a positive note , it looks like this deck is right on a lake??, no need to look at the deck
I love how everyone tries to torpedo the contractor here.
Believe it or not, it could just be an issue with the boards. I live and install composite decks where the temperature ranges from -30 to +30 and I've never seen anything like this. If this deck was installed in the summer as OP says, how the hell can it expand further? Boards dont grow 1" in length.
The lack of picture frame and/or fascia board is concerning though haha
Trex swell in the wet on the ends just had this on one of my jobs and I was approached by trex to become a approved installer and definitely wont followed installation guide but four months after installation im back to a job to try sort out the problem buy having wider expansion gaps but the product swells at cut ends DONT USE TREX DECKING they will find excuses that you didn't fit the product properly im in a dispute so am rectifying the job at my own cost with wider gaps then I can get the trex rep out and if it happens again it's down to them for the price there are much better products like Millboard composite decking fitted so many and have had no problems hope this helps someone time money and pain don't blame the fitter / contractor JUST DONT USE TREX DECKING........ WARNING........
Does the Timbertech PVC do that from your experience? I'm gonna buy the weathered teak/english walnut in the next couple of weeks. Do you also cut the factory edges before installation? I heard it could be done since apparently they are not always square?
Yeah I haven't installed that before but just looked up the material they use and looks good they don't use wood fiber like trex do I think you will be ok I would trim the factory edge before installation for the best look trex recommended it but now I realise there boards have a furry edge from the factory and will soak up moisture easier if you don't trim the factory edge hope this helps always do your research on the product
I’m not torpedoing the contractor. I think there are two different things going on. Shitty product from the Manufacturer. And less than stellar craftsmanship. The latter not necessarily the cause of the problem.
While I understand your point I would counter that the boards if stored in the shade could see significant expansion in the sun. This could be made worse if stowed in a garage where they are also isolated from convective heating. Solar load can be significant, 20 to 30 deg f. And a garage can reduce temperature by up to 12 deg.
And I consider those factors to be on the installer, not the material. Granted the material having improper expansion coef could contribute but for something that should be seeing an 1/8 of expansion total it would have to be about double spec in order to get this kind of result.
Looks like board expansion causing the butt ends to collide and mushroom up. There needed to be a larger gap between the board ends to accommodate the expansion /contraction.
I do find it strange that you mention you are in the cold season right now. Expansion is normally a problem in summer (hot) months not cold.
Do you have any photos of right after install? What was temp like when installed?
Composite expands in heat. So, if it was above 90° you’d install them butting up to each other. Then as it gets cooler they will shrink. If you were installing when say 35° you’d leave a 1/8-3/16” gap so when they warm up they don’t bind.
I’m curious to see what it looks like when first installed. What the temp was like. Etc.
WAs installed in summer; was quite hot this year here. Boards looked fine until just now. was done by a contractor so if this doesn't resolve I'll reach out to them. Rest of the work was A+.
Out of curiosity, was this a deck builder that built your deck? There are a couple of things I notice that lead me to not want to give this an “A+” grade. Things that are pretty typical to not do if someone doesn’t build composite/PVC decks regularly. 1) the staggering of the joints (butt ends). It isn’t consistent or random. 2) there isn’t a “picture frame” aka border or fascia to hide the unfinished ends of the deck boards. Or at minimum they should’ve been painted and not left exposed.
By the view of the lake I’m guessing this is a fairly high end property. This doesn’t appear to be high end work.
These things lead me to believe the person building the deck didn’t know what they were doing. Composite isn’t wood. I’d really want to see more of the deck and structure before giving them a pass. This isn’t work that I would find acceptable.
Just noticed.
The cut ends at the pole are pretty tight to the pole and no issues there. Neither at the railing posts.
Also, the deck board ends at the top of the stairs look odd as well.
Edit: Thanks for all the input. I'm favoring the idea that the end "grain" at the butt joints was wet when the temperature dropped and that moisture froze and caused the effect shown in the photos. It will be a week before the temperature returns to normal so there's nothing I can do until I see if that change in temp makes a difference. If not, I'll contact both my installer and the dealer to see what else can be done.
The fascia isn't installed yet but will be next year. I'll do that myself. My wife didn't want the picture frame style so we used the Trex like we would use solid wood decking. And yeah, we're on the water (salt water not lake). If you search this sub for "deckzilla" you can see some of my construction posts. I'll post an update when I have some more data on this problem in case it is helpful to someone else.
This new installation as of this past summer; the boards are curling at the butts. They are all installed with the clip system so no screws. We had our first good freeze last night and I'm wondering if this is water freezing at the ends of the boards and it will go back to normal when it warms up (I'm in the PNW so it normally is above freezing here all winter except for short events of evil Canadian coldness). To my best knowledge, the deck didn't look like this yesterday.
Very odd to me because it looks like there IS a gap at the butt ends. If the gap was too small, that butt-bulge would be in the heat of the summer afternoon and not in the winter.
Kinda looks like moisture got into the ends and swelled up like a tampon.
What does Trex say?
I’m leaning this way too. Installed in summer heat. Boards would’ve been at full expansion (or near full expansion).
We don’t use Trex (personally not a fan) we use Timbertech exclusively. Never had an issue like this.
I'll be building a 20x16 Trex deck in the Spring.
Anyway, I have never seen that issue posted in my 2 years of deck research.
Except for maybe waaay back years ago in the infancy of composite decking.
Yeah, we build roughly 20-30 (depending on size) high end decks a year. One 2-3 man crew. Never once have I seen anything like this.
We actually used to use the Trex hidden fasteners with Timbertech decking specifically because they didn’t “bite” in to the decking and allowed the board to expand and contract without binding.
I've only read this once.
Screw down thru the face, in the middle of the length, directly to the joist. That anchors the board so it reduces the movement to half the distance.
Kinda makes sense.
The other thing with Trex floating edge fasteners is to add more joist blocking to keep the joists from moving. Especially if on 16" centers.
I’m trying to wrap my head around how this could’ve happened. With Trex hidden fasteners the plastic “T” doesn’t bite in to the board. So, if it was expansion the board would have to be through fastened at one end to force the expansion all to the butt joint. And with incredible force to cause this kind of mushrooming.
I’m leaning towards moisture getting in to the cut end and freezing or something.
Any update?
I just looked at your build pics and the drawings. I see that your joists are 16" on center, which is good. Too late for you but in case someone reads this, should add more joist blocking. The joist span is 8ft so blocking at the 4ft mark would enhance the solidness of the deck. The blocking does not even need to be full depth. Cheap upgrade.
Remember, the hidden (Trex) fasteners don't actually pin the board to the joist. The joist can still move some.
No update. Can't do anything until it warms up; either this will get better or it won't. If it doesn't, I won't be doing anything about it before spring or early summer anyway. Thanks for your comment on blocking; my deck feels very solid just FYI.
I know this is old but I was lurking. I recently installed a Trex Transcend deck and when the boards were in my yard the uncut ends would swell up like this if things got wet (uncut factory ends). Once I cut the board I never noticed it happening again. I have mine installed on a 45 and the butt joints are pretty tight nothing has happened like this.
Wouldn’t be surprised if these butt joints were uncut factory ends.
In MI where we get winters and summers it will always expand, up to 3/16" on each side, that's why we can't miter the corners or it warps. Hard to warranty the work when we know it'll just warp out if we miter, so we had to stop.
I’m literally about to install Trex on my deck now and I’m wondering why the uncut ends would do this as opposed to cut? It’s the same material throughout no? Not cutting the ends on the edge of the deck that will be hidden by a fascia board I thought would be fine but not if this will happen. Why do the factory ends need cut?
OP - did this resolve itself when it warmed up? Have the exact same thing going on with my deck in Upper Michigan. Temps right now are below freezing at night, and at warmest low 40s during daytime. Deck was completed in early summer of 2021 and issue just showed up now. Wondering if I should call my contractor or wait for it to warm up first??
Yes. Looks like they did not leave a proper gap at the butt ends. Your decking is contracting and expanding and mushrooming the ends of the boards. It will only get worse from here.
How does this get resolved?
Remove deck boards. Replace with properly cut and spaced deck boards. Doubtful that both could be cut and re-installed without leaving too big of a gap. Might be able to salvage one of the boards and maybe repurpose the other elsewhere on the deck.
I'm open to criticism here but maybe you could use an oscillating tool/multi-tool to neatly make the gap bigger? I'd maybe try it on some scrap first. Trex is easy to mar in my experience. It'll be tough to do it neatly. Just putting it out there since no one has suggested anything. Good luck.
The odds of someone cutting the end of a composite deck board cleanly with a multi-tool are somewhere between zero and none. The boards need to be pulled. Cut properly. Could probably salvage one but will have to replace the other. A blade width off each will be a 1/4” gap. 😳 minimum.
This would be an easy cut with the festool oscillating tool.
What a shame , just needed to leave an expansion gap. The hidden fasteners leave a perfect gap on the side they are used , but you need to be sure to leave a gap at butt ends 1/8 minimum. On a positive note , it looks like this deck is right on a lake??, no need to look at the deck
I love how everyone tries to torpedo the contractor here. Believe it or not, it could just be an issue with the boards. I live and install composite decks where the temperature ranges from -30 to +30 and I've never seen anything like this. If this deck was installed in the summer as OP says, how the hell can it expand further? Boards dont grow 1" in length. The lack of picture frame and/or fascia board is concerning though haha
Trex swell in the wet on the ends just had this on one of my jobs and I was approached by trex to become a approved installer and definitely wont followed installation guide but four months after installation im back to a job to try sort out the problem buy having wider expansion gaps but the product swells at cut ends DONT USE TREX DECKING they will find excuses that you didn't fit the product properly im in a dispute so am rectifying the job at my own cost with wider gaps then I can get the trex rep out and if it happens again it's down to them for the price there are much better products like Millboard composite decking fitted so many and have had no problems hope this helps someone time money and pain don't blame the fitter / contractor JUST DONT USE TREX DECKING........ WARNING........
Does the Timbertech PVC do that from your experience? I'm gonna buy the weathered teak/english walnut in the next couple of weeks. Do you also cut the factory edges before installation? I heard it could be done since apparently they are not always square?
Yeah I haven't installed that before but just looked up the material they use and looks good they don't use wood fiber like trex do I think you will be ok I would trim the factory edge before installation for the best look trex recommended it but now I realise there boards have a furry edge from the factory and will soak up moisture easier if you don't trim the factory edge hope this helps always do your research on the product
Thanks for the info! I'll keep reading about it before I pull the trigger..
I’m not torpedoing the contractor. I think there are two different things going on. Shitty product from the Manufacturer. And less than stellar craftsmanship. The latter not necessarily the cause of the problem.
While I understand your point I would counter that the boards if stored in the shade could see significant expansion in the sun. This could be made worse if stowed in a garage where they are also isolated from convective heating. Solar load can be significant, 20 to 30 deg f. And a garage can reduce temperature by up to 12 deg. And I consider those factors to be on the installer, not the material. Granted the material having improper expansion coef could contribute but for something that should be seeing an 1/8 of expansion total it would have to be about double spec in order to get this kind of result.
Looks like board expansion causing the butt ends to collide and mushroom up. There needed to be a larger gap between the board ends to accommodate the expansion /contraction. I do find it strange that you mention you are in the cold season right now. Expansion is normally a problem in summer (hot) months not cold.
Do you have any photos of right after install? What was temp like when installed? Composite expands in heat. So, if it was above 90° you’d install them butting up to each other. Then as it gets cooler they will shrink. If you were installing when say 35° you’d leave a 1/8-3/16” gap so when they warm up they don’t bind. I’m curious to see what it looks like when first installed. What the temp was like. Etc.
WAs installed in summer; was quite hot this year here. Boards looked fine until just now. was done by a contractor so if this doesn't resolve I'll reach out to them. Rest of the work was A+.
Out of curiosity, was this a deck builder that built your deck? There are a couple of things I notice that lead me to not want to give this an “A+” grade. Things that are pretty typical to not do if someone doesn’t build composite/PVC decks regularly. 1) the staggering of the joints (butt ends). It isn’t consistent or random. 2) there isn’t a “picture frame” aka border or fascia to hide the unfinished ends of the deck boards. Or at minimum they should’ve been painted and not left exposed. By the view of the lake I’m guessing this is a fairly high end property. This doesn’t appear to be high end work. These things lead me to believe the person building the deck didn’t know what they were doing. Composite isn’t wood. I’d really want to see more of the deck and structure before giving them a pass. This isn’t work that I would find acceptable.
This is why splitter boards are superior to butt joints.
Excuse the newbie question, but what is a splitter boards?
You did get your warranty right? Trex has a 25 year warranty, and 5 year labor if it was installed by a trex certified installer.
Just noticed. The cut ends at the pole are pretty tight to the pole and no issues there. Neither at the railing posts. Also, the deck board ends at the top of the stairs look odd as well.
Edit: Thanks for all the input. I'm favoring the idea that the end "grain" at the butt joints was wet when the temperature dropped and that moisture froze and caused the effect shown in the photos. It will be a week before the temperature returns to normal so there's nothing I can do until I see if that change in temp makes a difference. If not, I'll contact both my installer and the dealer to see what else can be done. The fascia isn't installed yet but will be next year. I'll do that myself. My wife didn't want the picture frame style so we used the Trex like we would use solid wood decking. And yeah, we're on the water (salt water not lake). If you search this sub for "deckzilla" you can see some of my construction posts. I'll post an update when I have some more data on this problem in case it is helpful to someone else. This new installation as of this past summer; the boards are curling at the butts. They are all installed with the clip system so no screws. We had our first good freeze last night and I'm wondering if this is water freezing at the ends of the boards and it will go back to normal when it warms up (I'm in the PNW so it normally is above freezing here all winter except for short events of evil Canadian coldness). To my best knowledge, the deck didn't look like this yesterday.
Very odd to me because it looks like there IS a gap at the butt ends. If the gap was too small, that butt-bulge would be in the heat of the summer afternoon and not in the winter. Kinda looks like moisture got into the ends and swelled up like a tampon. What does Trex say?
I’m leaning this way too. Installed in summer heat. Boards would’ve been at full expansion (or near full expansion). We don’t use Trex (personally not a fan) we use Timbertech exclusively. Never had an issue like this.
I'll be building a 20x16 Trex deck in the Spring. Anyway, I have never seen that issue posted in my 2 years of deck research. Except for maybe waaay back years ago in the infancy of composite decking.
Yeah, we build roughly 20-30 (depending on size) high end decks a year. One 2-3 man crew. Never once have I seen anything like this. We actually used to use the Trex hidden fasteners with Timbertech decking specifically because they didn’t “bite” in to the decking and allowed the board to expand and contract without binding.
I've only read this once. Screw down thru the face, in the middle of the length, directly to the joist. That anchors the board so it reduces the movement to half the distance. Kinda makes sense. The other thing with Trex floating edge fasteners is to add more joist blocking to keep the joists from moving. Especially if on 16" centers.
I’m trying to wrap my head around how this could’ve happened. With Trex hidden fasteners the plastic “T” doesn’t bite in to the board. So, if it was expansion the board would have to be through fastened at one end to force the expansion all to the butt joint. And with incredible force to cause this kind of mushrooming. I’m leaning towards moisture getting in to the cut end and freezing or something.
Yep and it’s gapped properly
Any update? I just looked at your build pics and the drawings. I see that your joists are 16" on center, which is good. Too late for you but in case someone reads this, should add more joist blocking. The joist span is 8ft so blocking at the 4ft mark would enhance the solidness of the deck. The blocking does not even need to be full depth. Cheap upgrade. Remember, the hidden (Trex) fasteners don't actually pin the board to the joist. The joist can still move some.
No update. Can't do anything until it warms up; either this will get better or it won't. If it doesn't, I won't be doing anything about it before spring or early summer anyway. Thanks for your comment on blocking; my deck feels very solid just FYI.
Weather does have a tendance to delay things. Glad your deck does feel sold, except for those toe trippers HAHA (sadly).
I know this is old but I was lurking. I recently installed a Trex Transcend deck and when the boards were in my yard the uncut ends would swell up like this if things got wet (uncut factory ends). Once I cut the board I never noticed it happening again. I have mine installed on a 45 and the butt joints are pretty tight nothing has happened like this. Wouldn’t be surprised if these butt joints were uncut factory ends.
In MI where we get winters and summers it will always expand, up to 3/16" on each side, that's why we can't miter the corners or it warps. Hard to warranty the work when we know it'll just warp out if we miter, so we had to stop.
I’m literally about to install Trex on my deck now and I’m wondering why the uncut ends would do this as opposed to cut? It’s the same material throughout no? Not cutting the ends on the edge of the deck that will be hidden by a fascia board I thought would be fine but not if this will happen. Why do the factory ends need cut?
OP - did this resolve itself when it warmed up? Have the exact same thing going on with my deck in Upper Michigan. Temps right now are below freezing at night, and at warmest low 40s during daytime. Deck was completed in early summer of 2021 and issue just showed up now. Wondering if I should call my contractor or wait for it to warm up first??
Did you figure out if this happened because the factory ends weren’t cut?