Construction 3 : The Tiger Cage

November 20, 2014

            Oaxaca gets plenty of water, but it all falls during three months, and the other nine months are desert dry. The day after our last sluicing downpour the morning dawned cloudy, but by noon the sky was robin’s egg blue with not a puff of white to be seen. It was October 24.

            “That’s it,” says Lalo. “The rainy season is over.”

            “It may sprinkle a few times,” Cynthia adds, “but the next real rain will be in May.”

            So where do our neighbors in San Pablo and Santa Cruz get their water during the nine dry months? There’s a reservoir, the Presa Jacaranda, a little way up into the mountains. It fills during the three rainy months and then is meted out by the Water Commission during the dry nine. Agricultural water flows through Santa Cruz and down to San Pablo via the zanja, the irrigation ditch on the spine of the long ridge on which both towns sit. In fact the zanja is the back boundary of our property. From the ditch, water is gravity fed, via a closely monitored schedule of access, down into the corn and alfalfa fields that checker the slopes below the houses. Water for human use comes down from the mountain in a pipe. Human use does not include drinking: that water is purchased at the village purification plant near the Municipio. The rights to tap the zanja or pull water from the pipe are hereditary, and most of our neighbors have been living on their land since the days when Sunday church meant trekking up to the pyramids on Monte Albán with offerings to the rain god. As newcomers and—gasp, foreigners—we do not have water rights. After living here for several years we may be invited to apply for rights and pay the hefty application fee. If we have integrated well into the community and are pulling our weight, the right to a toma de agua might be granted. It would be nice if Casiano and Claudia and Gustavo, whose family have been in Santa Cruz forever, could secure water rights before they turn the property formally over to us.


            So where do newcomer-foreigners like us—I say ‘like us’, but I believe we are the only foreign property owners in Santa Cruz,— how do we get our water. Three ways, actually: drinking water we purchase. Water for everything else we either buy from one of the pipas, the 10,000-liter tank trucks, labeled "Agua para Uso Humano,"

that ply the hills and highways. Or we capture the massive rains that fall during the three wet months.


            Think cisterns.


            From the beginning of this project we have insisted to Cynthia that our goal is to be 100% water independent. Water from our roofs will run into gutters and from there will descend along rain chains to catchment receptacles from which it will flow—thanks, gravity!—into a cistern. An electric pump will bring it up to where we need it. We already have a 30,000-liter cistern under the terrace of the Casita, and will have two more 40,000-liter cisterns under the front half of the Casa.

          The swimming pool up at the Casas del Barco only holds 20,000 liters. But then, it has a shallow end.

            The soil on the upper half of our property, where the Casa and the Casita are situated, is a kind of caliche, a hardpan that seems in places like rock, and in places like clunky dirt. The rock bits, left in the sun, crumble. Interspersed are actual rocks of all kinds, probably brought down from the mountain as outwash. What’s nice is that when you dig a hole through this mix, the hole holds its shape. What’s not so nice is that the caliche is hard to dig through and is not good for growing much except scrub. The lower half of the property is good agricultural soil. Good for making adobe, too, but more about that later.


            While most everything on this job is done by hand, occasionally Lalo allows a machine to contribute to the effort. Trucks, for example, do make deliveries of sand, gravel, rebar, and cement. Lalo contracted with Justo, the local backhoe artist, to dig the holes for the footings and for the cisterns. Justo, in his late 40’s, has been backhoe-ing for most of his life.

            “Who owns the machine?” I ask Lalo. “It must have cost . . .”

            “. . . over a million pesos. Justo does. His father owned a big piece of land up above the Presa Gutiérrez, and I think he sold a chunk of it to help Justo buy the backhoe.”

            It takes three full days for Justo to dig the holes and move the dirt around, and during most of the time Linda and I watch him, fascinated by his precision (like a six-year old instructed by her grandmother to color carefully inside the lines), and by his delicate touch. I think he could make that behemoth lift an wren’s egg without breaking it. The hole he digs for the cistern could easily hold a dozen eggs; for that matter, also a dozen Hummers of maybe a small circus.

            “How long before we cement the cistern?” I naively ask Lalo.

            “¿Colarla? Three weeks. Maybe a month.”

            “That long? And in the meantime . . .?”

            “In the meantime we get it ready to colar,” Cynthia answers. “This is the largest and trickiest part of the whole project.”

            “And the most expensive,” Lalo adds. “Iron for the varillas to reinforce the walls. All the mano de obra, the hand work to tie it into a tight skein. Ten tons of cement, maybe more. We’re going to bury your money in a big hole and then cover it up so you will never see it again.”

            “Wait until you see this process!” says Cynthia.

            And see we do.


            The crew’s first task is to neaten the sides of the trenches, push back the loose dirt from the upper edges, and make certain the floor is absolutely clean. A flat-bladed shovel, then a brush and a dustpan, are the instruments of choice. Tidying up takes a couple of days.

            As with all other parts of the substructure of the Casa, the next stage is to lay down a thin cover of concrete so that everything that follows will build on a clean, flat surface. That requires a full day and a bucket brigade.



            The weight of the water in a 40,000-liter cistern is not trivial, nor is the force that it exerts against the cistern walls. The cisterns are built into the slope on the south side of the Casa, so that while the cistern’s north wall is braced against the caliche of the hillside, the south side is braced against air. Not so sturdy, that, especially given the fact that Oaxaca, like much of Mexico, has a penchant for seismic events. The solution, Cynthia explains, is to enclose each of the cisterns in cement walls poured into an iron cage, over-engineering everything to minimize the possibility of a catastrophic collapse. Now a month of preparation doesn’t seem like a long time at all.

            Think of the cistern like the hull of an old-time ship. The hull is longer than it is wide. To strengthen the sides of the hull, the ship builders fit ribs, sturdy timbers that have been carved or bent to conform to a cross section of the hull. The ship’s ribs help keep the water out. The cistern’s ribs, made of 3/8” rebar, bent to fit the walls, will help keep the water in. Cynthia orders a couple of tons of rebar, each piece a long loop that when laid out straight extends about 10 meters. Using a crimping tool to hold each piece fast, and a tube that fits over the end of the rebar and is long enough to supply leverage, each piece is given two right-angle bends, leaving it the shape of a staple: one section for the north wall, one for the floor, and one for the south wall. These “staples” will be fitted every eight inches along the north and south walls. For the east and west walls, the short sides of the cistern, a single bend will do: a single rebar will not reach all the way across the “keel” of the cistern. The L-shaped rebar pieces will have to be wired tightly together in the middle of the floor.  

            Once the ribs have all been wired into place—it takes about a week— horizontal pieces have to be woven through them. The edges and corners—the stress points—have to be reinforced with rebar castillos whose component pieces are also shaped by hand. This used to be done by cutting rebar pieces into the appropriate lengths, and then bending the pieces around nails hammered into a beam to make rectangles of the desired size. But the nails bent, or slipped, and the whole operation was awkward, sufficient for single bends, [PHOTO 4a] but imprecise for complex ones. Lalo invented a master molder and had a forge build it for him. With it, a man can produce a rectangular support for a castillo in about a minute and a half. [PHOTO 4b] The man does, and over the week he bends more than a thousand of them for the castillos of the two cisterns.

            With these raw components, the master assemblers, with Hermilo supervising them, gradually build up a cage that would easily confine a lion or a tiger, that would thwart a rhinoceros trying to escape, and, presumably, will keep 40,000 liters of water from blowing out the south wall and flooding Calle Independencia and our downhill neighbors.



Once the cage has been completed, it has to be tightly encased in wood, inside and out. These are the forms into which the concrete will be poured. Scrap lumber that has been used for a hundred tasks over the past few months is repurposed into flat, tightly-seamed panels that are painted with toasted oil to seal them. The panels are very heavy. Gangs of men lower each one into the hole and wrestle it into place against the tiger cage where it is wired in so tightly that the pouring concrete cannot budge it. Cimbrar la cisterna takes another ten days.



            Cynthia and Lalo spend hours together at our table on the Casita’s porch calculating the volume of the cement that will be needed to fill the cistern’s wood-formed walls. The entire cistern has to be filled in a single, continuous pour of concrete, because any seam in the walls would be a potentially fatal weak point. As we eavesdrop, and sometimes contribute, it becomes obvious that these will be the largest cisterns that the team of Lalo and Cynthia have ever built.



            “Are you going to mix it all by hand?” I ask, picturing in my mind’s eye a pod of 5 potbellied cement mixers, a cloud of cement dust rising over Santa Cruz Etla, and a hundred men portaging cement to the rim of the cisterns in an unending bucket brigade.

            “We haven’t decided yet,” Lalo and Cynthia say almost in unison.

            Cynthia goes on: “There’s a new kind of cement; premixed. We’d bring it in in a truck. It is very fine, and it sets up very fast, and it is very strong. They pump it in with a hose under high pressure.”

            Linda and I remind her of all the arguments against using premixed concrete that she had marshaled for us when we poured for the Casita.

            “It didn’t make sense for the Casita, but this is a really big pour.”

            “The regular way by hand is strong enough,” Lalo adds. “Actually, way stronger than strong enough. And we can do it. With enough workers, in one long day.”

            “Relative cost?”

            “About the same, as far as we can figure,” says Cynthia. “And the concrete will be of uniform texture and quality, and probably stronger than if we do it by hand.”

            “Fewer people for the pour,” says Lalo, “but much more mano de obra in the set up. The main problem is that this stuff is so fine, and so liquid when they pump it in, that if there is the tiniest hole in the cimbrado, the tiniest crack in the wood, the concrete is likely to come squirting through it and running all over the site. I’m not sure we could stop it. It sets up fast, and would be the devil to have to clean up.”

            “And we’ll decide ....?”

            “When it’s time. The truck needs a three-day advance notice. Let’s see how it goes.”

            We revisit the issue the next day, running through all the pros and cons. And the next day. And the next. We sit in the shade on the terrace of the casita. The “Arqui,” Cynthia, and the master builder, Lalo, are in substantial agreement. The trucked concrete will probably be better, and stronger, but there is substantial risk, and the risk is making them both very nervous. Also the labor cost for sealing every pinprick in the cimbrados is substantial. The tried and true is ...well, tried and true. And way more than strong enough to do the trick. Lalo and Cynthia seem to be looking to us to recommend one or the other, as if we had one iota of relevant expertise.

            Linda looks at me and her eyebrows make that interrogatory upward flip: punt. I turn to Cynthia.

            “So you’re really not sleeping at night, worrying about this poured concrete?”

            “I know it’s going to be alright. But still . . .”

            “If it does begin to spurt out,” Lalo picks it up, “it will go all over everything. And it sets so fast, that the cleanup will be ...”


            “And costly.”

            Linda and I flash each other the ok-we-are-in-agreement look.

            “The tried and true,” I say. “Experiment next time, on something smaller. On somebody else’s property.”

            “One more thing,” Lalo says. “You know that open space between the two rectangular cisterns?”

            “The one we decided to fill in because even though it is ideal for storage there is no easy way to get into it or out of it?” I say.

            “Yes. I’ve been thinking, since it is already enclosed by the walls of the other two cisterns, and they are plenty strong enough, let’s make it a third cistern. Another 20,000 liters.”

            We leave the porch and pick our way around the construction site, looking at the heavily walled space in between the two rectangular cisterns.


            “Concrete the floor, put a sealer coat on the walls. We have to roof it with losa anyway, since it is the connecting piece of the front terrace. Maybe an additional 10,000 pesos.”

            Linda and I do a reprise of the ok-we-are-in-agreement look.

            “Let’s do it.”


            It is Saturday noon. Lalo makes telephone calls. On Monday morning we can expect three truckloads of gravel, two of sand, and 15 tons (!) of cement in 50-kilo bags. If anyone had asked me any time during the last half century, “Do you think you will ever find yourself paying cash for 15 tons of cement?” I would not have had to think very long before giving my answer.


            Monday comes. So does the gravel, sand, and cement. Lalo and Hermilo direct the 26 workers to make everything ready for the Great Pour, down to the last detail. Paths to and from the material staging area are calculated, and about twenty wood plank bridges are laid over the trenches for the foundation walls. What with the trenches and labyrinth of bridges the site begins to look a little like Venice. The cimbrado on the tiger cages is checked and checked again. Lalo gives the men a pep talk, telling them that tomorrow we will start early and work until it is done, all three cisterns in a single continuous pour. He’ll bring in another 6-8 men to add to the bucket brigades, and nobody will break for lunch. Cynthia and Lalo prep us to lay in soft drinks and pizza to feed the famished crew when it’s done. I don’t think we calculated in the commissary expense when we estimated what this project would cost.



            Tuesday, November 18, it all goes like clockwork. Everyone shows up, the bucket brigades work with stunning efficiency, we have enough material to do the job. It doesn’t rain, and there is enough intermittent cloud cover that no one swoons with sunstroke. No one falls into the holes. The full buckets of sand, gravel, and water, and the sacks of cement that fuel the concrete mixer must weigh 40 or 50 kilos each, as do the buckets of wet concrete that are poured into the cistern walls. Even so, the porters heft them to their shoulders with a smooth grab and lift; with them they trot to the maw of the mixer or from the mixer to the cistern walls. They pour where one of the master builds directs them, and then run with the empty bucket back to the supply site and do it all again.

            I timed them. From shoveling the bucket full, to dumping it and returning to fill it again, took from 45-90 seconds, depending on the lineup to load and the lineup to pour. From the opening clankita clankita of the cement mixer to Lalo’s shouted “All the tools, back in the bodega” takes six hours, during which not one of the 26 works ever stops or even slows down.



            Tools stowed, hands washed, cement dust brushed from trousers, shirts, and hair, the men sit down on the remnant piles of gravel and sand. At Hermilo’s direction, two of the men have set up a rough table across two sawhorses. Linda astonishes everyone by bringing out a plastic tablecloth. Lalo signals me to slow things down. The pizza man is late. We ordered five supersized giant pizzas with assorted toppings and I expect a van will be pulling up shortly. Using our household buckets, I haul out 3-liter bottles of soft drink, paper plates and cups. Lalo has brought one case of beer.

            “Only one case? These guys have worked without stop all day long. One case won’t go far.”

            “One bottle each is a treat; more than that is an invitation.”

            “To . . . ?

            Lalo spreads his hands and shrugs his shoulders in the universal gesture for You-Figure-It-Out. Cynthia—checking the time on her cell phone—punches in the number for the pizza place. Before she finishes we hear a motorcycle and see a young man whose face is hidden by a white helmet wrestling his bike up the road to where the men are sitting. On the back of the bike is a tower of supersized giant pizzas.

            If the bucket brigade was fast and efficient, the circle of men taking firsts and seconds and thirds of pizzas moved at the speed of a carnival Tilt-a-Whirl. From first tantalizing odor to six empty boxes took less time than it takes to write it.


            And the pizzas were delicious.