A little bit about upper deck benchwork

I took video of the whole thing, so if you learn more by watching me do things, I’ll cross-post them to here once they’re up.

To start with: The plan. The whole thing’s just made of sturdy fun.

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If it looks like a big ol’ bunch of truss bridges, that’s on purpose. It’s an incredibly sturdy shelf. Now, the whole thing is on a grade from the helix (where that weird little tail piece is) to the sort-of-one-turn-helix that’s in the bottom left corner – and I don’t mean the track is on a grade, the BENCHWORK is. The track’s on a 2.6% grade all the way from the pulp mill to the summit, gaining 30 inches, and for some of that run the clearance is extremely precious. For this reason, the benchwork is also sloped.

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The most challenging aspects of the design were the creeks – Shields Creek and Farr Creek. For Shields, I had a bit of room to play because the backdrop could be quite far forward at McCormack Creek, directly below.

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Farr Creek wasn’t quite so lucky, and the valley bottom will have a rather large lip at the lower end to accommodate the benchwork without having the benchwork foul the lower deck. My original plan called for it to be 3″ above the pulp mill, whoops!

The basic construction, as you can see pretty well in the last photo, is L girders on the back and front with joists in between. It’s all made from lumber ripped from 3/4″ plywood cut as precisely as possible in terms of angles.  The whole thing is hung on 1x4s (nominal) from these special L girders on the ceiling:

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When they run perpendicular to the joists, they’re screwed directly into them, but otherwise they’re attached to 19″ wide sheets of plywood. Nice and solid.

The vertical members that hold the layout up have another purpose: At the corners, they but together and are screwed every 5″ or so. This gives a huge amount of rigidity. Speaking of rigidity, the 1x4s do have a certain amount of flex, so I added some steel U channels that happens to be 3/4″ wide to the sides of the 1x4s for extra sturdyness. You could use whatever is rigid and suits you best, I originally planned to use steel bar, but it was about $8 for a 6′ piece, and the U channel was free!

For the creeks, I simply made sure that everything had a bracing piece going in every applicable direction. Make sure you colour-code your plan! In mine, reds are the vertical supports, yellow is the regular height deck, blue is the extra-low front girder, and greens go from regular height to the extra-low height.


The bigger red one is a 2×4 that I connected down to the lower deck for added stability. I would have put it all the way to the floor, but it would have blocked access to the helix. Couldn’t have that!

To visualize all of this, here you go. It will eventually have a sheet of 1/4″ plywood to stop all movement dead, dead, DEAD.

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The rest was much more simply framed. For everything, it was made from plywood ripped into strips of nominal lumber, 1x2s, 1x3s, and 1x4s (.75×1.5, 2.5, and 3.5″ respectively.)  The outer members are L girders made of 1x3s with a 1×2 flange, screwed and glued. Make sure you do this right! Take advice from my video here. The bracing members in between are all 1x3s. I cut them at the proper angle after using a program called Cutmaster 2D to plan out all my cuts. It doesn’t take into account angled or beveled cuts so you have to do your own little trig calculations and bear with the extra little bit of waste for this type of benchwork, but with somewhere around 100 pieces of lumber it helped me make the most of my lumber. When planning, avoid any angled or beveled cut at a greater angle than 45°. Trust me.

To assemble it, make sure all your cuts are as precise as possible in terms of length, angle, and bevel. I put the 1×2 flange of the rear girder on top, and the front girder on the bottom. You only have to do this if it’s sloped front to back. A little trick to make it all snug is to turn your lumber until it lies along the back of your mitre saw (which is set at 0’) and cut off just the right amount to squeeze under the flange of the girder (so the cut is 3/4″ long)

To get them in place, smother them with glue, then hold them firmly in place while screwing them in. I’m working on getting videos done as a visual tutorial, so if all that is confusing to you, you won’t have to wait too long!

Under the helix I decided to just a simple grid of 1x4s.

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The next section has Porcupine Creek in it, and had to be fairly deep as a result. The section after that has to be close in elevation to the duckunder, so I decided to have them 4″ apart vertically with a joining plate of 3/4″ plywood in between the two.

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Anyway, that’s where I’ve gotten to. Check out the video tutorials, they’ll probably be more cohesive and coherent.  Time to get loads of work done!


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