Weekly DIY: Copper Garden Trellis

April 18, 2007

A few years ago, when we started getting our garden together my wife wanted to have a trellis for some roses to climb on. We looked at various options. There are pre-built or kit trellises, but those are expensive. We could build one with wood, but it would need to be treated with preservatives (nasty chemicals) and would need maintenance. We ended up deciding to build one using simple copper pipe. While that may not immediately seem the greenest option, I think the durability and life-cycle of the material makes it a good choice.

Now, if you are thinking to yourself, "I can't solder copper pipe; this is too advanced for me!" don't worry. This project requires nothing more than some straight copper pipe, some copper connectors (tees and elbows), and some strong two part epoxy. I also used a couple of steel reinforcing bars (rebar) to help fix the trellis in place. The only tool you'll need is a pipe cutter or a hacksaw to cut the pipe into the size you need.

I can't offer you process photos for this project as I have for some other DIY projects, because we completed this several years ago, and we didn't take pictures of it at the time it was going up. However, I do have a picture from last summer so you can see how it has aged into place, and how the roses have climbed all over it.

This list is for the trellis as diagrammed below. (The diagram and the photo do not match; many variations are possible.) You can adjust the design and get much more decorative once you understand the general idea here. You can also simplify things by using all 3/4" diameter pipe, rather than using both 1/2"and 3/4" as I have done.

Determine your configuration and make all your cuts before you begin putting anything together. Since the pipe comes in standard lengths, working with even divides of the pipe will help to minimize waste. Cutting six 2' long sections from a 12' long pipe makes good sense, for example. As with the cold frame DIY a few weeks ago, this is another project where the dimensions listed are approximate, and should be adjusted to your own needs.

Materials list:

  • 1/2" diameter copper pipe – 24' length total, cut into 12 pieces each 2' long
  • 3/4" diameter copper pipe – 40' length total, cut into 16 pieces each 18" long, 12 short connector pieces each 6" long, and 4 gable pieces each 30" long
  • 3/4" diameter, 90 degree copper elbows – 2 needed
  • 3/4" diameter, 45 degree copper elbows – 4 needed
  • 3/4" diameter to 1/2" diameter copper tees – 24 needed
  • two-part epoxy suitable for outdoor exposure

To cut the pipe you can either use a hacksaw or a tube cutter. The tube cutter is an inexpensive tool that gives you nice straight cuts. Just tighten it onto the pipe at the point you want to cut. When you turn it around the pipe, the blade scores the pipe. After a complete turn, tighten it slightly more and wind it around the pipe again. Repeat a few times until the cutter has cut through the pipe. You can quickly make all the cuts you need, so you'll have a set of tinkertoy parts.

You can do a dry fit of your trellis parts before you put it all together to check the configuration. The best approach to take is to assmble smaller sections as sub-assemblies, and then put those together (after the epoxy has set) to get the larger whole assembled. Put together one rectangle and let it set. Then add the next rectangle to it, and again let it set. That way you can keep the verticals as straight as possible. When working with epoxy, you should only mix up as much as you can use in a short period of time. To make the connections, spread the epoxy around the pipe and then slide it into place in the connector. Some epoxy will ooze out, but don't be too concerned about that. Having it stick out like that helps keep water out of the joint.

Copper starts out shiny like a new penny, but oxidizes to a brownish patina after a while. In time, it will potentially go even further and take on the greenish hue that old copper gets, but that takes decades to develop, so don't set your hopes on having that look anytime soon. Most copper pipe you get at a hardware store will have printing on it with identifying information about it. Don't be too concerned about this, since it will all but disappear as the pipe ages and oxidizes. Find an epoxy that finishes in a brownish shade, so it blends in nicely when the trellis has aged in place for a while.

If you are going to use steel rebar to fix the trellis in place, just drive it into the ground like a nail so that it is buried a couple of feet, but with some bar still sticking out of the ground. I also wrapped some paper around the rebar before I lifted the trellis and set it on top to keep the dissimilar metals from coming into contact with each other.

Copper might not immediately seem to be the most environmental of choices. But it will withstand the elements extremely well. (Ours has already lasted through 5 Michigan winters with no problems and the joints are still secure.) When the trellis is finally taken down, the copper can even be recycled. A wood trellis would probably not be good for anything besides scrap ot the end of its useful life, and would not last nearly as long. Copper has a lot more embodied energy in its manufacture, but it wears and weathers extremely well, and can be largely reclaimed.


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