[ENG] Construction 114: Side alley underground structures (2) - archaeological window part 1

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In putting into practice what I previously assumed, many details will inevitably suffer some changes. However, the basic subject remains the same: a "window" that allows one to peek underground, discovering hidden archaeological remains, perhaps belonging to the same foundations on which the Domus is built.

While initially I hypothesized the presence of Roman remains, highlighted by the composition of the wall in the opus reticulatum style (see drawing), later I opt for a structure compatible to the tower, probably the oldest element of the whole complex (at least in the lower part) . It could be an old defensive tower connected to the city walls and later incorporated to the new building ...

But these are only assumptions, not supported by certain documentary proofs.

The main feature of this window will be the round shape, at first just an hypothesis due to its complexity. In fact I would like to preserve the inside from dust and the best choice for that would be the use of an ordinary or acrylic glass, even if I'd prefer the first one. However, while I have good chances to cut the slate into the desired shape (and in case of mistake the material do not lacks), I'm not equipped to cut the glass.

At this point the case comes to my rescue: the table lamp that I use while working lacks the protective glass. In fact, years ago I removed it to prevent the bulb from overheating, placing it in a drawer in the midst of many odds and ends.
With a good dose of luck I can find it almost immediately and I transform it into the starting element for the construction of my window.

So, once the pieces that form the external facing are finally made, it's time to move on to its content.

Using two rather large blocks of slate as a base, I start laying the stones, forming a wall that represents an ideal continuation of the tower. In fact, the window is located exactly under its base.
On the left, a small brick arch gives access to an underground corridor, which will then be obstructed by dirt and debris, making it barely visible.
Then I insert a thicker stone, as if in that point the masonry rested directly on the underlying rock. I have collected several of these stones on the bed of a river and they will be useful for the construction of the pavement and the tower, getting very close to the materials actually used in the Genoese medieval constructions.

After the rock is the turn of the amphora, the only element that remained unchanged since the first studies. For now it's only a laying test, then the clay pot will be varnished and "soiled" adequately. In this phase I must pay particular attention to the fact that the elements do not protrude too much from the base. This would hinder the laying of the slate slab which must be perfectly vertical and in line with the concrete base.

Meanwhile, using a cardboard cylinder as a support, I'm building half a stone vault with which I will close the upper part of the underground chamber. Once closed, it will rest on the perimeter slab projecting ideally towards the outside.

After a first filling of the joints with cement grout, I prepare a bed of soil, pebbles and cement that will act as a base for the amphora, now well finished and ready to play its role.

To uniform everything, I spread a little sand that I fix with some light sprinkling of spray glue.

The lower part of the "secret chamber" is practically finished. Now I have to insert the vault, which has meanwhile stiffened and been removed from the cardboard support. I provisionally place the lower slab and a couple of random stones to support it while the glue is drying. Just out of curiosity, they're a river pebble (I already talked about it) and a scrap of a marble laboratory with round cutting tests on it.

Despite the rudimentary tools, even the circle that I cut on the slate slabs did not come out badly, and what follows is a preview of how the window will look once closed.

slate, glass, gravel, stones, sand, soil, transparent varnish, vinyl glue, spray glue
tweezers, pincers, sandpaper, hacksaw, files, Dremel with diamond cutting wheel
SIZE (in cm):
window diameter: 6
slate slab thickness: 0,6


[ENG] Construction 113: Side alley underground structures (1) - tests and studies

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I believe the time has come to put my hands on the underground structures that surround Domus, left out from the construction so far. Before starting the climb to the first floor, with all that comes with it (arches of the loggia, stairs, vaults, etc.), I'd like to see the streets that run on two sides of the building completed: on the front, an alley slightly sloping, paved and driveway, under which a small covered stream flows; sideways, a narrow and steep alley partially covered with steps that reaches the secondary entrance passing the external wall of the tower.

Although it has been a long time since I first thought about the construction of these streets and the filling of the subsoil, I find myself having to face a job that is still full of unknowns, mainly due to the lack of convincing tests. Let's jump back a couple of years and see what these tests are.

My intention was from the beginning to make a pretty rough filler using wooden boards that once removed will leave the materials of which the soil is composed: stones, sand, cement or other things. My big doubt was about the resistance of this filling, because if the material is too fragile it could break on the edges releasing continuously wastes that would make it difficult to clean and preserve. For this reason I carried out a first test using glue in the mixture.

The result did not convince me. The glue in such a large quantity took a long time to dry and did not completely lose its whitish color. The next day the only dry part was the surface exposed to air, while the rest of the block was soft and easily deformable. In addition, the glue tends to withdraw and this could alter the structure in an unpredictable way.

Using only cement instead of glue the result would certainly be more resistant, but I wanted to prevent the subsoil from taking the same gray color as the base to make it clear that it is the natural ground.
So I decided to combine the cement with a mix of gravel and soil that I picked up next to a dirt road, adding to the mixture a little glue diluted in water.

The test block was hard and resistant and took a discreet brownish color, even if on the surfaces there was no trace of the gravel as I would have liked ...

Let's go back to the present.
After these tests I decide to go on with soil and cement, and that is why I build the wooden formwork that will allow me to pour the mixture directly over the walls.
To give better grip to the cement I take advantage of some nooks and crannies between the stones to insert screws and wire. This armor will prevent the alley from collapsing from the rest of the construction.

The wooden mold shows some bolts that will serve to open holes in the concrete block (I will reveal its usefulness later - much later) and a metal tube through which one of the led bulbs will pass to illuminate the basement.
I pour the mixture into the formwork and wait with (im)patience for it to dry to see if the result convinces me to keep on this way or if I need to try another method.

Ok. I need to find another way.

I take a moment to pause and wait for the light to come on with a brilliant idea that will let me overcome this terrible disappointment. When I finally see that light, the desire to bring to reality what I have in mind is overwhelming. I realized what my mistake was: I wanted to fill up the subsoil on-the-fly to quickly proceed to the completion of the alleys, forgetting that this IS NOT the way in which the Domus must take shape: every corner has a reason to be; every surface, even the more insignificant, has potentialities that must be studied and brought to maturity. In this case, the subsoil can offer much more than just a brown wall and a few cracks, and it don't matter if the work will be longer than expected.

With a pencil I outline the basic characteristics of the subsoil. The side surfaces will be completely covered by slate tiles, except where different holes will get into the underground corridor and the river (for which I have already made the stone bed).
In addition there will be another circular opening from which it will be possible to observe part of an underground environment. Here I can play with fantasy: Ancient roman structures? A secret room? Stratification of materials and human remains?

What is hidden under the Domus?

(to be continued...)

vinyl glue, beach pebbles, cement, soil, gravel, wire, steel screw, aluminium pipe
pincers, tweezers, pan, palette knife, soil scoop, wooden planks
SIZE (in cm):
28 x 3,8


[ESP] Construcción 115: Subsuelo del callejón lateral y ventana arqueológica (3)

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¿Por dónde íbamos? Ah ya, la construcción de la media bóveda de piedra para cubrir la cámara subterránea.

Con este elemento la construcción de la ventana arqueológica debería llegar a su fin. Pero como a menudo ocurre, antes de cerrarla definitivamente aportaré unos cuántos cambios.
En este caso solo se trata del añadido de nuevos detalles, dictado por las usuales repentinas inspiraciones nocturnas. Sí, porqué a veces antes de acostarme me quedo observando la Domus en busca de posibles aportaciones o intentando visualizar las partes que aún quedan por construir. Luego, durante la noche, mi procesador sigue trabajando en el tema y a la mañana siguiente me encuentro esbozando nuevas ideas y modificaciones del proyecto.
Por eso, una vez terminada la construcción del muro subterráneo me toca eliminar una de las piedras que lo componen para dar cuerpo una vez más a mis fantasías.

A la cámara secreta le falta todavía una historia, algo que la haga "viva". Pero mientras quede oculta no habrá nada que contar...
Aquí es dónde entra en escena nuestro hombre.

Usando un bastón como palanca sobre uno de los sillares, el tipo consiguió tirarlo abriendo a la vista el local subterráneo.
Pero... ¿Quién es este hombre? ¿Qué está buscando? ¿Está solo o hay alguien con él? Me parece ver una luz...

No, en realidad no hay luz todavía. ¡Pero pronto la habrá!

El bloque formado por el muro, la bóveda y el arco sigue separado del resto de la construcción, pero después de los últimos retoques con cemento y tierra ya puedo pegarlo definitivamente a la base.

Entonces coloco la loseta perimetral inferior, en la cual he abierto los agujeros necesarios para el montaje y la semi-circunferencia que sujetará el cristal de protección.

Atravesando el subsuelo, un largo tubo de aluminio alcanza la cara trasera de la Domus permitiendo el paso de una nueva bombilla de neon.

Y ahora veo claramente la luz de una antorcha al otro lado del muro. Evidentemente el intruso no está solo...

Todavía no me queda muy claro qué ha venido a buscar y cómo ha podido llegar hasta aquí. Probablemente abrió una brecha también dentro de la vieja cisterna, en desuso. Espero poder aclarar este misterio, quizás tras otra noche de descanso...

pizarra, cemento, tierra, madera, cola spray, cola blanca, tubo de aluminio (de unas viejas cortinas extensibles), figura de pastor para pesebres, bombilla de neon de 4mm
pinzas, cortador, serrucho, Dremel con punta diamantada (para los agujeros), pincel, esponja

Costruzione 236: Copertura del primo piano - travetti e tavolato

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Finita la posa delle travi principali è la volta dei travetti, che attraverseranno le falde del tetto poggiando sulle travi collocate con la tecnica a cavalletti e puntelli descritta nel post precedente. La distanza fra i travetti dovrà ricalcare esattamente quella tra le mensole in pietra del perimetro, la cui funzione è quella di sostenerne le estremità tramite staffe d'appoggio.

Inizio la posa dalla falda laterale, più grande, estendendomi fino alla diagonale, rappresentata da una trave più sottile di quelle sottostanti e a sezione quadrata per offrire un appoggio ottimale alle tavole.

Inserisco i travetti sulla trave dormiente attraverso scanalature effettuate sul momento che ne migliorano l'incastro, altrimenti troppo superficiale. Nel frattempo, mi occupo anche di completare la muratura interna con un ultimo strato di cemento. Ormai la chiusura è vicina, e una volta collocato definitivamente il tetto mi sarà impossibile effettuare ulteriori ritocchi dall'interno.

A causa del grado d'inclinazione dei travetti, mi vedo costretto ad estendere le scanalature anche al paramento esterno, potenziando ulteriormente l'incastro del tetto sui muri perimetrali. A posa ultimata, la griglia rappresentata dalle travi e dai travetti (ancora interamente rimovibile) si incastra perfettamente con il resto della struttura.

Come si vede nelle immagini, anche sopra le travi longitudinali ho inserito dei segmenti di legno delle stesse dimensioni dei travetti, che non hanno una funzione strutturale ma forniscono una base d'appoggio extra per il tavolato.

L'incastro del tetto sulle murature esterne viene completato dalla posa di alcuni mattoni negli spazi tra le scanalature, che hanno la funzione di chiudere anche l'ultimo spiraglio tra il muro e il tavolato, la cui posa inizia proprio dal perimetro esterno.

Le assi vengono allineate alternando i giunti tra le diverse tavole e posando le estremità sempre al di sopra di un travetto, come nei normali solai. Sulla diagonale di falda invece combaciano secondo la linea obliqua del tetto. Ogni tavola è fissata alla superficie superiore dei travetti con una goccia di colla.

La posa procede spedita e in breve la superficie del tetto risulta interamente coperta dal tavolato. Sbirciando l'interno dall'unica porzione di parete ancora aperta posso farmi un'idea pressoché definitiva dell'aspetto del nuovo ambiente che si viene a creare al di sotto. Manca qualche ragnatela e la polvere che inevitabilmente andrà ad accumularsi in questi locali che nessuno si prenderà la briga di pulire...

A questo punto il lavoro si sposta nuovamente sul perimetro esterno, lungo il quale devo procedere al pareggiamento dei travetti, e già che siamo in zona faccio un piccolo test di posizionamento di una delle staffe.

Questa spaccatura nella parete è davvero provvidenziale per verificare l'interno del sottotetto. Anche il micio sembra apprezzarla, forse nella speranza che faccia la sua apparizione qualche topolino. Penso che la lascerò aperta fino a quando il tetto non sarà del tutto terminato.

Ora comunque posso procedere alle ultime rifiniture prima di dedicarmi alla decorazione interna della soffitta. Prima tocca alle estremità dei travetti, le cui teste vengono assottigliate con il rullo abrasivo del Dremel. Una leggera rastrematura concava darà al perimetro un aspetto più affusolato e leggero.

Poi finalmente posso collocare l'ultima fila di tavole lungo il perimetro, tagliandole longitudinalmente perché il bordo del tetto risulti a filo con le teste dei travetti.

Ultimo tocco: qualche intaglio sulla superficie visibile dei travetti e della diagonale di falda su consiglio del maestro ebanista, che voleva addirittura scolpire il volto di San Michele sulla testa della trave d'angolo (ovviamente in cambio di un lauto compenso). Meno male che sono riuscito a zittirlo in tempo e il committente in quel momento stava ispezionando gli interni. Con tutto il ritardo che abbiamo accumulato, ci manca pure la testa dell'arcangelo!

Ed ecco la copertura in legno in un unico pezzo, pronta per essere verniciata e collocata al proprio posto. Ma lo vedremo nel prossimo post, insieme all'arredamento della soffitta...

mattoncini, cemento, rami secchi, listelli per modellismo navale, colla da contatto, colla vinilica
tenaglie, pinzette, carta abrasiva, lime, cutter, Dremel con rullo abrasivo, righello, matita
MISURE (in cm):
sezione travetti: 0,3 x 0,3
distanza fra i travetti: ±1
sezione tavole: 0,5 x 0,1
estensione perimetro: 10,8 x 16,8