If you remember, last year around this time (almost) all of my posts were about the construction project I was involved in: Building a round structure with a tire wall and a reciprocal roof. Thanks to the Covid lockdown we were forced to stay here a few weeks longer than anticipated, but once the roof beams were up and the travel restrictions eased, all of us went back to their respective homes, to come back and finish the roof.
Finally the time has come, and we're back together in Mazunte, with an exciting challenge: covering the beams and turning it into a green roof. And just as before, I am excited to share the process on Hive.
Protecting the Beams
Anybody with basic knowledge about wood structures will shake their heads at the notion of using partially green logs on the roof, then leaving them exposed for a year before actually covering them. And that's exactly what happened here. Though we made sure to treat each royal palm log with a few days in a boric acid bath to deter termites from infesting them, they needed a couple of months at least to completely dry, before we could apply the protecting varnish.
We set them up in the circular reciprocal fashion, where they are going to stay for good, and let them dry out completely. Granted, the rainy season was upon us, so we covered their top sides with a plastic tarp, leaving it open at the bottom, to encourage air flow. All of us admitted that this wasn't the most ideal way, but since there was little else we could do, we hoped for the best.
As it turned out, the rainy season kinda fell short this year. So much so that our mango tree, we planted four years ago, dried up completely. What a bummer! But at least the roof looked fine. We went ahead, and gave the entire structure a good sanding, then proceeded with varnishing it. Half of them are already finished.
Adding Intermediary Beams
Reciprocal roofs can bear an incredible amount of weight, but where the beams fan out towards the bottom, the triangles are simply too wide, so the beams have too much space between them. To make sure that it would support the green roof, we added intermediary beams to reinforce this area. To attach them to the beams we used the same means as linking the logs together: two threaded rods running through holes drilled through the logs.
First Cover Layer: Boards
Once the intermediary beams are in place, and everything has been varnished nicely, it's time to start covering the roof. First we add a layer of boards, before moving on to the pond-liner, the gravel, the soil, and the plants, as part of the green roof.
Using pine, or other low-cost and even lower quality lumber would mean having to redo the roof in a few years, once the green layer has established itself. No way we were going to do that! Fortunately, there is excellent quality tropical hardwood growing right around the neighboring village. They are expected to last over fifty years. I'm not exactly sure if it is harvested sustainably, but the surest way to give back for what we take, is planting some coralillo on our land, the same as what we have done with the royal palm.
Unfortunately, getting the boards, having them milled to the proper size, and making cuts ourselves have proven a formidable challenge with the hard and heavy material. As always, though, in the end we manage. Thus, we have almost covered the first triangle.
You will notice how the lowest boards on the bottom end of the logs are almost horizontal, while on the top they are increasingly slanted. That is a typical feature of reciprocal structures, after all the right beam is sitting on top of the left one. In the end this will give the whole cover a cool undulating look, but at the moment it's still a bit scary. Screwing down the smallest pieces on the top, while sitting on an increasingly narrow surface, which on top of all is becoming slanted as you go up... Right, just don't think about it, and never look down!
Unlike last year, time in not on our side. I'm leaving Mazunte mid April, and the rest of the group within a couple of weeks. We still don't have all the boards we need, and the pond-liner has also created unexpected problems. Okay, we got enough dirt, that should not be a problem. So let's see how we can get this roof covered over the next few weeks.