Composite deck material

[kulas44]

After considerable testing and tearing up a lot of this stuff I think I have figured out a good way to use it on a boat deck. Resawn to 1/4 inch by 2 inch and dovetailed on the underneath. It seems to stick extremely well to plywood using polyurethane (PL Roof Repair) glue. I tried several kinds and brands of epoxy but they all gave up after weeks or sometimes months of exposure. The best epoxy was FCI's 4 to 1 using milled fiber as a filler to mayo thickness. Triple dovetails give the planks a mechanical grip, neccessary because nothing wants to stick to the polyethylene in the stuff. The best plank material I have found is Tropics made by Veranda, it has more wood and less P E. I used the "no screws or bungs" system to fasten the material to plywood. Screws and fender washers to hold it down until the glue sets up. Then pulled the screws and filled the grooves with PU. The screws set the spacing between planks, so no holes in them. So far it looks like this could be a very good way to get a great nonskid deck that is WAY tuff and looks pretty good to. Zero maintenance is also nice, plus, under the stuff is pure polyurethane so water will have a tough time getting through it. What do you guys think ?

[donald branscom]

Do you mean composite plywood?

I would NEVER use composite on a boat anything.
When it gets moisture in it it will swell up.
Furniture material for landlubbers.

I would not glue plywood to deck beams unless it is an all plywood boat. What if the deck ever needs replacement? You would have to grind off all of the glue and wood from the deck beams without ruining the deck beams.
There is no such thing as ZERO maintenence except maybe while you own it, but the next person will be doing it.

When you say triple dovetails I have no idea what that could mean.

[kulas44]

Composite decking as in polyethyline/wood extruded boards. Absolutely weatherproof. And, plywood has been glued to deck beams almost forever, it's tried and true and normal procedure, but has little to do with the original post. I have a pool deck that I built using "ChoiceDeck" composite lumber 8 years ago and it looks new to this day. Pressure wash it once each spring. It's nonskid and cool to walk on even in 100 degree temps out in the sun. Does not fade or turn gray, never splinters or rots, so yes I would say it is as close to no maintenance as can be had right now. It just doesn't glue very well, hence the dovetails to give a mechanical fastening.

[Thad Van Gilder]

composite decking is made with wood dust made from low quality, rot prone wood. Not pure polyurethane!!! When the wood rots away you are left with a plastic sponge. Also, the wood is not completely sealed from the atmosphere. Look at it under a hand lens... you can see what I mean.

I second the question as to what what could a triple dovetail be...
I have no clue.

Do you actually do these things to your boat?

-Thad

[kulas44]

If you don't have a clue what you are talking about...don't talk !

[mcdenny]

I've wondered about using composite decking too but was always put off by the weight. How does this compare to teak?

I read the Veranda website info - the wood part is maple wood flour. Maple is not very rot resistant but they guarantee the stuff against rot for 15 years so maybe it would last. They suggest gluing with construction adhesive but don't say which one and cover their butt by saying test carefully first - duh.

I don't know what tripe dovetail is either.

[sdowney717]

http://www.thefreedictionary.com/dovetail

I think he means the bottom of the plastic board is triple grooved as this would help in gluing it down.
I would think PL premium poly constr adhesive would work on this.

Also, about the potential for rot, negligible. The stuff is embedded in a plastic matrix so little air or water could get to the wood?

[kulas44]

Exactly, 3 small dovetails routed into the bottom to provide a mechanical fastening. I did not try PL premium, as this project will require gluing the decking to a glassed over surface. It's been my experience with PL premiuim that it is GREAT for wood/wood joints but not for any thing else, it just doesn't like to bond. As far as I know it can't be beat for gluing wood, and I use a lot of it. For this application the PL urethane sealants (door&window, roof repair, or concrete repair) seemed a better way to go. They grip about like 5200, tenacious. As far a weight goes, I have not weighed this stuff but it does feel heavier than teak. I will calculate the difference for my deck. As for rot, no way, about like mixing wood flour with epoxy, water can't get to the wood to start the rot. One of the major deterents to using this is that it has very little structural strength. As a deck surface over plywood/F.G. strength is not required. Low maintenance, toughness, nonskid and looks are it's strong points.

[donald branscom]

Thanks for the clarification on the composite deck material.
When you said "deck" I was thinking boat deck NOT deck like at a house. "Composite decking as in polyethyline/wood extruded boards.
Below is a photo of what I thought a dovetail joint is.

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