All good things come to an end at some point. And if everything works out, the goals will be reached by the end. That is how things managed to work out finally for my friends in Mazunte: they completed the roof! The only thing I am a bit sad about, is that I wasn't there with them to share the moment of victory. But now that they have left the property, and are with me in Mexico City, before flying out to their respective countries, I got to hear all the exciting stories, and look at the photos they've shot of the last steps of the construction.
Where I Left Off... and Why:
Looking back at the last posts in the series, it seems like I wrote about all kinds of things, from yoga to vegan cooking, except for the construction itself! The reason for that was simple: for the second half of my stay on the property work was put on hold, simply because we were waiting for the material. The endless waiting game was interrupted by occasional battles with the people who were in charge of procuring the wood, milling it, transporting it, then repeating everything because what they brought was of such abysmal quality that we could not accept it. Finally, on my last day before leaving, the wood arrived, and work could finally commence... without me, though.
Solving the Unevenness with Triangles
At first the entire roof space had to be covered with boards. Laying them out on the bottom end of the vigas, they were pretty much on the same level, but as we went up, the right side became gradually higher than the left one.
Not surprisingly, in the reciprocal roof the right viga is sitting on top of the left one. If the board teeters a bit at first, it can be forced down with a screw... but after a while this becomes increasingly unreasonable.
So the solution was to cut it in two triangles. Sure, it may look weird, but only until all the surrounding boards start adopting the same pattern. In the end it actually looks kinda cool, in a rustic way.
On the bottom part of the roof we built a small canal for drainage. The completed roof is not only supposed to be covered with plants, but all the water seeping through the plant-and-soil layer is supposed to be harvested (in a cistern that is yet to be built...). To facilitate drainage, this canal would be filled with gravel, but only once the pond-liner is in place.
Enter the Pond Liner: EPDM or HDPE?
Okay, for the green roof we need a waterproof layer, so that the perpetually moist soil layer won't damage the roof beams. The material that comes most highly recommended for this purpose is what you would use to line a pond, so the water won't seep away downward. And the best of such pond liners is EPDM, which Earthships also use for their gray-water-planter cells. I had the chance to work with this neat rubber-like material before. It is thick, slightly elastic, very pliable, and in a way it reminded me a bit of a neoprene wet-suit. Unfortunately, here in Mexico it was virtually impossible to get EPDM of the size wee needed. So we had to opt for the much heaver, and less pliable HDPE instead. Even that seemed tied to incredible challenges...
On my last day in Mazunte the greatest challenge was organizing the transport of the pond liner we had purchased. The closest provider was in the metropolitan outskirts of Mexico City, and the dimensions of the folded package they gave us made it seem like we would need to rent an 18-wheeler. After days of frantic communication, my friends finally managed to have it brought in for a reasonable amount. Also, the package was nowhere nearly as oversized as they stated. But by that time I was gone.
Still, the entire sheet weighed around 300 kg, so putting in on top of the roof was a bit of a challenge. They used the beetle to pull it on a rope while five people were adjusting it from behind, but had to realize that the little car was not strong enough. Even when they hitched the van with the powerful V8 engine in front, it proved to be a major challenge. In the end, they finally got it up, only to notice how the wind kept getting underneath it, trying to carry it away. Like 300 kg is not enough to hold itself down!
Last Minute Planting Party
So like it or not, my friends were forced to bring the roof project properly to the end, adding the gravel and dirt layers, just as originally intended. Their time in Mazunte was coming to a close, so it put them in a bit of a hurry, still they decided to invite some friends for a planting party, on their last day before leaving.
This must have been the nicest day of this entire season: finally having a finished roof, which would be protected from the rain, and lovely people who came to help out putting some young plants in the soil. In fact, with all these plants in place the impending rainy season is more than welcome now.
Among the plants chosen for the roof culture is passion fruit, pineapples, nopal cactus, snake plant, as well as many native seeds already included in the soil.
The center hole of the roof was covered with some leftover HDPE. This is where we will have to build a more permanent feature for opening and closing it. A little palm-thatched roof, or a small geodesic dome maybe? We're not sure yet, but that is for next year anyway. At the moment we are all glad to have made it this far, and we're all looking forward to coming back and continuing on this cool project... next year, when the rains have passed, and the association has got some more money.
Take a Look at my Previous Posts on this Exciting Construction Project:
Lost and Found: The Promotional Video for the Theater on the Beach
Back in the Circus of Mazunte
Up on the Roof Again
Teaching a Reciprocal Roof Workshop
Green Mazunte
Yoga for Construction Work
The Quickest Tent Structure: Building a Flex Yurt
Vegan Days with Fabiola