Waterproof deck idea - use composite?

I have been thinking of a way to replace an existing deck & provide a water resistant it only covers another deck below so full waterfroof is not needed. I also HATE the gaps in normal decking as they are leaf & stick traps. Leaves will not move when blowing & sweeping is not much better. You have to pull gumleaves out one by one - a PAIN. A flat surface would be so much less work.

I don't want to use compressed fibro & tile as it will be too thick, to messy to install (lots of cutting) & too heavy.

I can not put sheet roofing (such as trim deck or csutom orb) below the joists due to construction issues & also I don't like the look of this system.

I have investigated aluminium decking from G James http://www.gjames.com.au/brochure/sunlanderdeck.pdf which has built in guttering, so the water resistance & ease of installation would be there - but I'm not sure that aluminium is the look I want.

I had looked at composite decking (mix of sawdsut & plastc) before, but the installation requires a minmimum 4mm gap for expansion, so no ability to make a water resistant surface. However, I noticed recently that ModWood have released a new 137mm x 23mm solid board that spans 450mm (their older system was hollow, & it also would not span the 450mm joists) . This got me to thinking. These composites can be worked with normal woodworking tools, so maybe I can route the boards to a shiplap profile to allow for movement, while providing the falt, water shedding surface I want.

What do you think - will it work?

BTW, the composites do not have issues with cupping & movement is supposed to be quite minimal - mainly thermal rather than moisture.

Shiplap would still need a gap at the top, and would eliminate the ability of some of the debris to fall through. I've found pine needles are the worst kind of debris. Short of caulking all the joints (a major PITA), it might help to caulk only the part of the joint above the joist to a sloping profile for shedding the debris; or insert a compressed foam triangle there. (Still a PITA, though.)

Joe

Mate you can buy timber already router with the extra groove for a mastic bead the same as a boat..... Costs a bit but will achieve your result.... Boards come T + G but the top side of the tongue is over cut for the mastic which seals it.... You then have to use the right sealer on the top as deck oil won't work with the mastic.... Theres a guy in Brookvale who gets into it for boats and architectural houses

cheers Utemad

www.dialadeck.com.au