Building the Woodshed Reciprocal Roof

by ziggy on December 9, 2010 -- 1 comment -- Follow

I suppose I’m a sucker for reciprocal roofs. After much thought, April and I decided to go ahead with building a reciprocal roof over the woodshed. The original plan was to make a shed roof, but alas, I couldn’t bring myself to build a shed roof. I just really don’t like them. In the end, a reciprocal roof seemed to serve us best, aesthetically and functionally.

If you aren’t caught up on reciprocal roofs, check out my entry on how to build a reciprocal roof frame. The biggest difference between this woodshed roof and that of the house is the pitch. We built the walls of the woodshed to be taller up front by about a foot and a half so that the reciprocal roof would shed towards the back — in hopes that we could collect water more easily and collect it behind the building, instead of all around the structure. Normally, a reciprocal roof sits like a cone on a building, and water streams off at all points, but hopefully this tipped roof will send water more to one half.

reciprocal roof 00

Setting the roof rafters

Otherwise, the design is basically the same as that of the house, except we were working on a much smaller scale! The rafters were only as long as 8 feet, versus the 20 foot length poles for the house roof. Whew! Interestingly, though, it took us four attempts to get this roof right! Huh? I was pretty perplexed myself. But I think I know why. The first time, I completely staggered the rafters wrong, so that was my fault. But the next couple of times, we had trouble with getting the last rafter in place. The last rafter was to go in on the relatively flat half (the front side) of the building. So we were working with little to no leverage in placing it. I think the difficulties we had were due to the tipped nature of the roof — the fact that the pitch is nearly nonexistent at the front side of the building, and pretty shallow even on the back half.

It's solid!

Nevertheless, we finally got it right on the fourth attempt. Thank goodness. The design includes nine primary rafters that make up the circle, and another nine secondary rafters that were spiked into the primary rafters to split the span between rafters. I chose mostly black locust wood, with some osage and mulberry thrown in the mix. We encountered some interesting slippage between two of the rafters once we had finished placing them, so we decided to spike the primary rafters together (each one into the previous at the inner circle) for extra security.

Next came decking the roof. I decided to use the same 1x black walnut that I used for the house. This process is always a little tedious — sawing dozens and dozens of little boards fit to span the rafters and nailing them in. I spaced the boards a couple inches apart, again, the same way I did for the house.

One interesting creative challenge arose when I had to decide what to do with the inner circle. There certainly wasn’t going to be a skylight (this is a woodshed, after all…). I first decided I needed to span the circle with something, since it was too large to hold dirt with no extra support, unfortunately. I wasn’t too happy with my solution of taking two lengths of wood and making an X across the nice open circle, but then I had a great thought… April made an embroidery to go inside the inner circle, playing with that X. She spent a day sewing this:


You can’t easily tell by the photo alone, but the design is four trees, each one representing the four seasons. I love it!

Over the decking went some fabric (old bedsheets and burlap, in fact), and then cardboard. The fabric hides the cardboard from view inside the structure.

Fabric over the reciprocal roof rafters

I’ve been storing scraps of EPDM pond liner from the house roof since its construction, and we had the chance to utilize those scraps on this roof. We had large triangular pieces that we laid over the woodshed roof, trying to cover up the entire area. We had literally just enough material to do it! What made using those scraps possible was this EPDM EternaBond RoofSeal tape. It’s 4″ wide, super-super-super adhesive EPDM tape, typically used for repairing leaks. We basically taped the EPDM together, making one solid sheet. It seems to be working so far.


That’s as far as we’ve gotten. Soil will not go on until next year, unfortunately. But thankfully the shed is sealed from the elements so we’re finally able to use it!


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  • PJ Chmiel

    Beautiful work and a very nice writeup, I’m so jealous of all of your great little building projects! I don’t have any clay to work with here, so I’ve been thinking about earthbags, strawbales, etc. Keep up the great projects and thanks as always for the documentation!

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