QUARAI: THE CONSTRUCTION OF PURISIMA CONCEPCION (continued)
CONSTRUCTION OF THE CHURCH (continued)
The Second Level of Wood Construction
The Nave Roof
The most difficult part of the construction of Concepción de Quarai began at twenty-six feet above the ground. At this height, construction began on the platform along the west wall of the nave where the corbels and vigas of the nave roof would rest. At the same time, the roof beam platform on the east wall of the nave was built at a height of twenty-seven feet. The difference in height provided a one-foot slope across the 27 1/2-foot width of the church for drainage of the runoff of rain and snow melt. The masons built the roof with an additional slope of about three inches from north to south. This prevented pooling at the clerestory window and channelled the runoff to canales, or drainspouts, through the parapet that allowed the water to fall to the ground. The carpenters carved the canales from solid pieces of wood, making each canal in the form of an open-topped wooden channel about 4 feet long, 8 inches across and 7 inches high, with a U-shaped cross-section. 
At the same wall height several other wood elements went into the walls. On the facade, the carpenters set the beams which would support the roof of the porch, above the doorway from the choir loft to the front porch. In the east transept, they laid the sill of the high window opening eastward over the convento.
While masonry work continued in the area of the transept and apse, in the nave the masons and carpenters together began the construction of the roof. The carpenters had cut, trimmed, and carved twenty-nine vigas. The decorative carved patterns covered the sides and bottom of each viga and consisted of repeating geometric patterns down the center of each beam, framed with lines and smaller patterns along the edges of the wood. The carpenters probably painted the patterns in the same colors used on the church walls and the altars, predominantly white, blue, red, green, and black. They made no real attempt to cut the vigas exactly the same length, but most of the vigas were about thirty-five feet long. Each viga was 10 1/2 inches wide, and twelve inches high. The vigas extending across the nave at the buttressing towers were somewhat longer, ranging between thirty-seven and forty-two feet long. Even longer were the pair of vigas for the bottom of the clerestory window, fifty-six feet in length. 
Four corbels supported every viga in the nave, two corbels beneath each end of the viga. The visible end of each corbel was carved into an identical scroll-like curve on its underside, and covered with decorative patterns on the side faces. The 116 corbels were made in two lengths, about 7 1/2 feet for the lower corbels and 11 1/2 feet for the upper corbels. The lower corbels were set about four feet into the walls of the nave, while the upper corbels were set in about 4 1/2 feet. This left an exposed length of 3 1/2 feet for the lower corbels and seven feet for the uppers. Only the exposed surfaces received decorative carving.
The corbels were set on the spot selected for each viga and braced in place against the interior scaffolding. Then the stone wall was built up between the corbels. The masons laid large flat stones, eight to ten inches square, against the sides of the corbels, securing the stones in place with mortar. Then they built up the stonework between the corbels with normal, horizontally-laid stone, until the wall was flush with the top of the upper corbel. At this point the viga was carefully lifted from inside the church, turned, and lowered onto the corbels. The masons built the stonework up around the viga. They trowelled a layer of mortar about two inches thick on top of the viga, and then continued the construction of the wall. They added another one to two feet of stone as a parapet, so that the final height of the nave walls was thirty-one feet. 
At the north end of the nave the pair of clerestory vigas were set in place along the edge of the transept. The carpenters set the two beams side by side, each with their corbels, to make a double-width viga. The ends of all six beams (the two vigas and the four corbels on each side) extended along the south face of the transept, flush with the surface of the stonework, and then on through the transept wall to within three to four inches of the outer face. 
When the carpenters had set the lower clerestory beams in place, the roofing crews began work on the nave. The carpenters laid smaller peeled logs called latillas diagonally from viga to viga.  On top of the latillas they placed a layer of fiber matting to close the small gaps between the logs, and then began shovelling a layer of adobe about six inches thick onto the prepared surface. This was trowelled flat, shaped around the ends of the canales to insure proper drainage, and probably sealed with a layer of plaster.
The Apse and Transept Roof
The masons continued with the construction of the apse and transept upper walls and roofing. In the apse, the carpenters and masons placed three fifteen-inch-square beams at a height of 23 feet. These beams were intended to be the mounting points for the retablo above the main altar when it was installed. Two of the beams were set flush into the side walls. The third beam ran across the apse with its ends set into the side walls at the same height as the side stringers but was not set into the stonework. 
At a height of thirty feet, the construction crew began work on the roof of the apse. First they set the roof beams of the apse in place. Each was eight inches wide and 9 1/2 inches high, with a double set of corbels and vigas at the front, or south, side of the apse. The carpenters and masons put the apse corbels and beams in place in the same manner as those of the nave, except that the ends of the beams were set into the side walls only about twenty inches, with the ends of the corbels almost flush with the ends of the beams. Structurally, the beams and corbels had little strength with such a shallow inset, but they supported little more than their own weight. The carpenters laid only a plank floor on top of the vigas to close off the spaces between them. No layers of latillas, matting, and adobe were placed above the planks, because this was not the actual roof of the apse, but something like a false roof to give the apse the proper visual height. The true roof of the apse would be built later, seven feet higher.
The masons built the walls of the transept and apse to 32 1/2 feet, where they lifted the upper clerestory window beams into place. This was also a double viga. Each beam was 10 1/2 inches wide, 12 inches high, and about fifty-six feet long, supported on corbels of the same description as those under the nave vigas. The carpenters set thick vertical posts between the lower and upper clerestory vigas, a pair against each wall and two pair equally spaced along the vigas.  With the posts in place the upper and lower clerestory vigas became a single system strong enough to support the seventeen transept beams that would rest on them, the stone parapet above, and the latillas, clay and plaster layers sealing the roof.
The construction crew laid a second set of long beams on top of the vigas at the mouth of the apse. These were a double set of vigas, each 56 feet long, with two sets of corbels on solid beams beneath. These formed the supports across the mouth of the apse on which the transept roof beams rested. When these vigas were in place, the transept was ready to receive the high roof. The crew lifted the one hundred and sixteen corbels and twenty-nine vigas into place, building the wall up around each corbel as it was braced in position. The carpenters had cut the corbels and vigas with a width of nine inches and a height of eleven inches, slightly smaller than those in the nave. Over the clerestory window, the transept corbels and vigas rested directly on the clerestory viga, but stonework was placed between the corbels and vigas to secure them in place. 
The transept sloped downward toward the south about twelve inches and toward the east about three inches.  These slopes permitted rainwater and snow melt to flow to a canal set near the south edge of the east face of the transept. From the canal the water fell onto the roof of the ambulatorio, where it may have been caught in a storage barrel or allowed to run off to the ground. After the transept vigas and latillas were in place, the masons built up the stone parapets to a height of forty feet. This resulted in a parapet two feet high across the top of the clerestory window, and about 1 1/4 feet above the north edge of the transepts.
Over the apse they constructed a light roof on eight inch thick beams at the level of the transept roof. The north end of each beam rested on a transverse beam eight inches in diameter set into the side walls of the apse against the back or north wall. The south ends rested on the stonework between the transept vigas so that the upper surface of the roof over the transept matched the roof surface over the apse. Latillas were laid from beam to beam, running east-west.  This upper roof sloped down about six inches from the north edge of the transept roof to the north parapet of the apse. Here the rainwater and snow melt ran off through a canal set through the north wall parapet slightly off center to the east. 
The roofing crews finished the roof of the transept and apse as they had the nave. They rapidly laid coarse matting or onto the transept and apse latillas. These mats held the latillas in place and filled any cracks and gaps left between them. The crew then hauled bucket after bucket of adobe to the top of the church. This was spread over the matting, until a layer six to eight inches thick was built up. In the area of a canal the roofing crew formed the top surface of the adobe into smooth slopes down to the intake of the canal so that no ponds would form. Finally they may have spread a layer of lime plaster over the roof surfaces to reduce runoff erosion and to waterproof the adobe as much as possible. Because the process allowed some drainage of mud and plaster through the matting and down the interior wall surfaces, these final steps of roofing were completed before the final plastering and painting of the interior of the church.
In the meantime the masons continued work on the six tower buttresses. They built the facade towers to thirty-nine feet, the nave towers to forty-three feet, and the apse towers to forty-five feet. As a final touch they formed the top surfaces of the towers into flattened four-sided pyramids, to insure drainage and reduce runoff and frost damage. This completed the major construction work on the church of Nuestra Señora de Purísima Concepción de Quarai. 
Last Updated: 28-Aug-2006