Well said, Jon, I used redwood and cedar which has been in place for12 years now (for elevated track), and can find no rot under the ballast. This despite weekly sprinkling which also goes on the track. Even the portion that gets little or no sun is in excellent condition. Just a little fungus and moss on the ballast up here in fogland. The cedar was laid double ply, so to speak with drainage. The ballast was placed on top, retained with 1" x 1" redwood. I have actually found cedar to be the best since it appears to be less brittle, accepts nails or screws more readily without splitting . For ties on the 3-1/2" track I have also found cedar to be more workable. A few very low grades have developed as a result of minor earthquakes-- or whatever!
Only problem, if one can call it a problem, is losing ballast as the wood does shrink to some degree, as Jon says -wood does move! However, I don't learn from experience. Our deck was in great shape but I wanted to "dress it up to make it look prettier-- so-- I coated it with a waterproofing "recommended" junk. Now it stays wet forever and probably won't last as long anyway!! Geoff. I have heard many elevated track system ideas presented in this forum. And a >common element is "weatherproofing" various wood products as substrates. Many >more powerful coatings are suggested to prevent the deterioration of the >substrate. But as long as the substrate is wood, the coating will fail. Wood >moves, coatings don't. As soon as one moves with respect to the other, >failure >occurs and moisture is allowed entry to the vulnerable wood product. No >system >will work indefinitely. If you're going to use wood, use redwood or cedar and >don't coat it with anything, but provide perfect water shed to prevent >moisture >buildup. And using a penetrating oil (boiled linseed oil and gum turpentine >mixture) to soak the redwood will allow a very long lasting product. I have >gates with exposed glue joints that were treated with this mixture (and >nothing >else) that have lasted for ten years without degradation. Moisture settles on >them evey night, as evaporates by day. No delamination ! The moral : >DON'T try >to seal any wood product. It doesn't work. You must allow wood to move. And >filling the internal cell structure with something will impede the >absorbtion of >water. That's the best you can do. End of lecture ! > >royce (w) > >Jonathan Bloom wrote: > >> > When you can, please let us know more details about the construction. >> >> Ah....the gory details. >> >> Design criteria was: >> 1) low maintenance >> 2) easily removed and relocated (if we move) >> >> I initially decided on a modified PETS base with 10' minimum radii. The 8' >> aluminum box sections are supported by galv. pipe fastened to a flange and >> screwed to a free standing pier block. I used 1.25" diam. risers and a >> short piece of 1" at the top for vertical adjustment. The 1" slides inside >> the larger 1.25 which is tapped for a set screw. >> >> I originally intended to fasten 1.5 x 1.5 x .125 aluminum angle to the frame >> sections, about an inch and a half from the outside edge. One track rail >> would be supported by the outside box member and the other (inside rail) >> supported by this new piece of angle. The track ties would be fastened to >> the all aluminum base....thus no paint, no delamination, no maintenance. I >> purchased the angle and had the appropriate radii bent for the corners. >> Looked great. Really thought I had built a better mouse trap. >> >> One BIG problem I didn't anticipate. Rolling the angle into a radius put a >> wow into it. In other words, it was no longer plumb along its length which >> meant I would be shimming the center of the span by over a 1/4 inch unless I >> wanted a roller coaster railroad. (The Cricket would have been fine but the >> rod drivers wouldn't think this very cool.) After rolling, it was springy >> as heck so the only way to straighten it would be annealing and pressing. >> Should have had it built to spec originally rather than modifying it after >> the fact. That is plainly obvious now. Being tired of building and really >> wanting to operate, I decided to cut my losses rather than mess with it any >> further. >> >> Therefore, a 1/2" ply deck now resides on top, with two coats of a green >> Polyurethane non-slip "paint." Initially, it is a waterproof barrier with >> amazing adhesion, strength and supposedly UV resistant, designed for >> stadiums, pool areas, factory floors, etc. We'll see how long it holds up. >> Hopefully I've got a couple of years to think on it before the ply starts to >> pop apart. >> >> I'm still after zero maintenance. Maybe next time I'll hit the mark. I >> like the idea of half inch Trex and have also been thinking about poured >> light weight concrete next time around. >> >> Jon >> >
