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Thread: Composite decking questions

  1. #1
    Join Date
    Nov 2006
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    Question Composite decking questions

    Hi, all -

    I've done research and read what quite a few folks have had to say about composite decking materials, but I have a request to use it in an unusual manner and having never played with it, wanted to ask some advise. I've been asked to rebuild the step 'boxes' used in the bathrooms at my son's pre-school, and they are keen to use composite for what they view as a sanitary upgrade (the old ones are well-worn wood). These will be simple steps, built essentially like free-standing rectangular mini-decks. For fear of being tagged by the Creek's software for doing a search for "decking children," I thought I'd ask my questions and hope the answers are fairly straightforward:
    1. How 'splintery' (for lack of a better word) is this stuff? If I just countersink and screw the material from the top, do I need to be concerned about little feet potentially getting slivers?
    2. If I chamfer or round-over the edges with a router, do I need to worry about slivers? Tearout?
    3. How much cost and complexity do the 'hidden' fastener systems add? Obviously it's not as much of a question when building a multi-hundred square foot deck, but if I'm building eight 2.5sq.ft. mini-decks, I'm not up to paying $100 for a jig. I am, however, interested in the potentially added safety (see #1) and hygiene, and think it would look better, too.
    4. I've read that at least some of this stuff is still somewhat porous, is there a recommended brand that may have minimal issues? I'm not keen on providing bacteria breeding grounds for the school bathrooms. I expect they will clean them, but they may also assume 'plastic = less of an issue' and if that isn't true, I'd at least like to know.
    5. I've read that glues don't stick - is there a recommended way to end-join this stuff? I'm thinking that I would prefer to use the same material for everything, and for the rectangular box on the bottom, I'd rather not butt-join it at the corners. My first thought is to rabbet one end and screw through the rabbet into the 'end grain' of the other piece, but I'm trying to figure out my options - including potentially using dovetails or box joints with screws from the edge (i.e. from top toward floor). These will see a LOT of use, and I'd like to provide a near-bulletproof design.

    That's about it for right now, if anyone can help, I'd appreciate it!


    Thanks,

    daniel
    Not all chemicals are bad. Without hydrogen or oxygen, for example, there would be no way to make water, a vital ingredient in beer.

  2. #2
    Join Date
    Apr 2011
    Location
    Williamston, MI
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    Composite decking

    I recently installed Trex decking and found that it routs very easy and doesn't leave any splinters. There is a smooth side and a grain side and it can be installed with either side up. Smooth side up is easier to clean and leaves fewer places for crud to collect but it can get slippery when wet. They have it installed this way in the outdoor pool area at the Maumee Bay State Park in Ohio. I don't know how it glues. It requires pre-drilling if you don't want to raise a burr when surface fastening. I used the Trex hidden fastener system with slotted boards and it was a PITA to install. The newest hidden fastener system that was recently demonstrated on This Old House is the way to go but it requires a jig and special fasteners.

  3. #3
    Join Date
    Feb 2008
    Location
    NE Connecticut
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    695
    The town of Westport, CT has an entire playscape (large) made of composite decking. My son, his cousins and friends have played there many times and I have never seen anything that looked like it would give a splinter. Since it's at a beach, most kids are running around barefoot.

    The edges of most pieces look routed. The routed edges show some interior holes that I assume were bubbles that formed during manufacture. This might be an issue if you're looking for smooth surfaces that don't collect germs and dirt. I bet you could fill them with epoxy or something, though.

    All joinery seems to have been done with screws. Some screws have a raised lip around them so if I were building with screws I'd want to countersink.

    Good luck.


  4. #4
    Join Date
    Sep 2009
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    Medina Ohio
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    I've install a lot of composite decking and after the first few time you sweep it the are no splinters. I like the hidden fastener system as there is no screw holes to stick up and it makes a cleaner look. For me it is just as fast also.

  5. #5
    Join Date
    Dec 2008
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    Northern Michigan
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    Of the ones I have installed I prefer Azek brand. None have splinters that I have ever noticed. Cortex makes special screws and plugs to match almost every brand/color. Cammo makes a hidden fastener system that blind screws from the side, the homeowner jig is inexpensive, but I recommend the PRO model.

    Larry

  6. #6
    Join Date
    Nov 2010
    Location
    Amsterdam, NY
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    230
    Composites by design do not splinter hardly ever, if at all. It's one of their selling points.
    It also can be routed fairly easily, as long as the bit is sharp to prevent any tear-out.

    The hidden fastners work great and provide a much cleaner look. If you don't use them be very careful how close to the edge you screw them.
    They will split very easily, even with pre-drilling at times.

    I have used a few different brands and prefer the Azek (expensive) and the Timbertech (moderate).
    Not a fan of Trexx, and we wont' specify it on any jobs again due to issues with color fading, splitting, etc....
    But then again this will be inside and maybe not as much of an issue.

    Not sure how the steps are designed, but there might be some issue with concealed fasteners and one outside board having them exposed.
    Most fasteners are designed to provide the proper spacing for the next plank. Just something to think about.

  7. #7
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    Sep 2009
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    Medina Ohio
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    When I install composite without the spline cut in I use a biscuit joiner to cut for my hidden fasteners.

  8. #8
    Join Date
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    If you use screws designed for composite decking the screw heads will sit flush without any mushrooming, although they go in easier if predrilled. Some newer decking such as Veranda has a plastic coating which will not soak up stains but also will not look right if you try to route over an edge.

  9. #9
    Join Date
    Dec 2010
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    South Coastal Massachusetts
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    I used a 100% HDPE decking material instead of Trex.

    Trex (at least when I installed back in 2002) tended to a uniform silver finish after a year or so of UV exposure.
    My neighbor's deck faced South and showed this. It also supported the growth of moss, which could be removed by TSP.

    The plastic deck had none of those problems. It did expand along it's length considerably. On hotter days, you could hear it creak along the fasteners.

    One word about installation; start at your "SHOW" side, where you will see it from the street, and work back from there. If you start straight, you'll finish straight.
    And wear kneepads.

  10. #10
    Join Date
    Nov 2006
    Location
    Apex, NC
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    Thanks for all the comments, folks. I'm still not convinced this is the route I'm going to go, but your input has helped, thanks. The biggest minus, if you will, is the price is waaaay more than I could build these things out of wood. At least, at the local BORG, it is. (I don't need enough to warrant a big order off the internet, so I need to look locally.) As to the splintering, the stuff I've seen is either grooved on the bottom or flat (for a premium), but the top has a faux wood grain that seems pretty rough - that's more what I meant with my question, is that surface splintery or not(?). The slivers comment was more specific to cutting/routing, but it appears that my concerns are unfounded, there. The requested builds are basically 'half crate' designs, with four pieces fastened at 90º at the 'edge grain', with planks fastened across the top by whatever means are available. I'll keep looking, and I hope to find a sample to mess with before I commit to a price and delivery, but I've got a good idea based on the forum input - thanks!


    daniel
    Not all chemicals are bad. Without hydrogen or oxygen, for example, there would be no way to make water, a vital ingredient in beer.

  11. #11
    I've glued Trex with epoxy with no problems. Trex had problems a few years ago with the surface flaking off. I had that problem, contacted them and after an inspection, got a settlement check from them.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  12. #12
    Join Date
    Jul 2005
    Location
    West Chester, PA
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    I would highly recommend the AZEK material. First, it is "pure" plastic - nothing to promote growth of germs or what-not. Second, it would never splinter or deteriorate in any fashion when wet, even end-cuts. It also glues together well - using the proprietary glue or (as I discovered with some cutoffs when the deck was AZEK-ed last summer) just with ordinary multipurpose PVC cement.

    I highly recommend also those Cortex countersunk screws with plugs. IMO, these provide a sturdier fastening system and the plugs are VIRTUALLY invisible when the grain in the plug is lined up with the grain in the board.

    As to cost, I would try to find an AZEK installer or two in your neighborhood and beg, borrow, or steal (i.e., slip them a couple Lincolns) their cutoffs. For our 1400 sq. ft. deck, I retrieved at least 100 BF of cutoffs, some 6-8 ft. long (maybe one errant screw hole in one end) and I kept none less than 18". Time being money to these guys, this waste otherwise would just have gone into the dumpster.

    Don't exactly know what you have in mind, but I would consider the AZEK ledger boards for risers. These are ½" thick and 11" wide.

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