Ch.15 : Construction Techniques  
The Opus


Craticium       Quadratum       Caementicium      Incertum      Reticulatum       Mixtum     

Latericium     Vittatum     Signinium     Vermiculatum     Sectile     Spicatum   --  The Coatings     

The study and the buildings and excavations of an ancient city, based on the Sami archaeological principles, analysis of stratification and establishment of relative chronologies Involve la même process .. The use of objective methods dating is all we can-have-been used That materials. The history of the building takes shape in its apparent and visible to the invisible foundations. The history of the building takes shape in icts apparent and visible to the invisible foundations. ... In order for a search folder is full and rich, the archaeologist must also document the various architectural structures of the building, the archaeologist must document with as much precision coatings, floors, arches, careful study of the frame does not, of course, the use of written and iconographic sources such as archives left by previous archaeologists see writings 'earlier periods.

Major innovations produced by the Romans in the architectural field Were made possible, by the search for new technological solutions. They managed not only to improve traditional systems Etruscan and Hellenistic, but also to invent new ones. They managed not only to Improve traditional systems Etruscan and Hellenistic, goal aussi to invent new ones.
A landmark discovery was that of cement, Roman concrete ,: a fluid mixing lime, sand and water, he was cast in wooden crates for bearing structures, sometimes curved.  Other times the cement was amalgamated with gravel or fragments of brick and paid between the two side walls fill by giving, in the end, a work 'bag', a real siding.  The walls were built with different techniques, each diverse as needed; Were the walls built with different techniques as diverse Each needed. They called Expired Opus.


 OPUS CRATICIUM: Until the third century BC, the walls of private houses and public Were made dry, ie without using malts purpose only wood, clay and residual stones;.  Clay Was the only link entre thesis all items.
Opus Craticium book was a very low cost, regarded as the first method of construction of the walls in Rome in its first period of domination .. 

On a trellis frame, an assembly forming a frame welded square mesh of a mixture of all that is at hand, was filled with a tab of any kind of material bound together by plaster.
 A very good example at Herculaneum in the house Partitions with two-storey timber-framed building;  construction was described by Vitruvius as Craticii or Opus Craticium .This construction work may have been used for residential houses insulas cheap in Rome


Opus quadratum: structures into regular blocks parallelepipedale form.  In use since the Archaic period, purpose VII) debut VI) a.JC. century), it is the technique adopted in Rome in the most technical anciennes.This building was used by the Romans from the 6th century BC and over time, the precision and accuracy of the improved cutting block.  The technique continued to be used throughout the age of the Roman Empire, even after the introduction of mortar, and was often used to complement other techniques. The type of stone, block size, and how the blocks were put together, are d "are concepts that allow archaeologists to help the structures and construction techniques.

It consisted of large blocks of tufa divided parallelepipedale shaped square willing to dry first on simple file and using too homogeneous blocks, eventually honing the block cutting technique and putting too implement alternating with cut blocks of blocks arranged head through the wall;  to increase the stability they could be used, iron stirrups fixed with molten lead which created a kind of armor.  The technique of cutting the stone blocks was learned the 4th century BC, concepts of Hellenic culture. This type of construction continued to be used in large buildings also after the advent of opus cementicium


OPUS CEMENTICIUM: The Romans began to use the cemeticium opus, Roman concrete consisting of lime and pozzolan cement, already in the third century BC .;  this material revolutionized constructive methodologies of antiquity in all that he allowed the realization of large public buildings and works in a quicker time, using an easy availability of equipment, transportation and implementation, compared to the Classic square work.  Artwork cement was used for building foundations or as kernel dressed masonry on the sides at the same time built by masonry veneer in the same second core technical realization of the following layers: experts masters realized the facing for certain height using caisseforms (wooden crates ..) and less experienced workers could be paid within very fluid maltes successively and then pour the cement to consolidate the bursts of stones that they came so often bedridden chaotic or very regularly.  When the layer had solidified enough he proceeded to achieve the following;  the curtains could be brick or tuff block or other stone or travertine or marble also;  the latter could be better anchored to the core using cluster between iron plates or brackets embedded in the concrete;  who are the holes in the cement works of Roman monuments were performed to scroll through the support brackets and plunder the monuments of their coat or simply for iron anchors, as the holes in the travertine rock the Colosseum;  in the walls are being implemented latericium a series of holes arranged on regular files, as happens in the typical medieval wallings; it is on these holes they were made during the construction of the wall and used to be built on poles which were insured scaffolding during construction, and subsequently in the event of restoration work. Siding, depending on the type, were left in sight or plastered and embellished with frescoes, sealants, curtains and other decorations noble stones.


OPUS INCERTUM: with the introduction of malthe and Roman concrete is facing necessitates the use, consistent with the core, composed of elements of smaller dimensions.  The oldest type of siding is the random length, consisting tufelli pyramid-shaped, with the top of the wall immersed in the cement core and the irregularly shaped base left in sight.  The oldest examples of this technique in Rome dating back to the first decades of the second century à.C .: Not to be confused with the opus or insertum isodomon, set assembly.

Was initially arranged more precisely and to give it as flat as possible surface.  It is for this reason it was mainly used to pave the floor, anyway assimilating stone chips and pebbles mixed with Malta in the Roman cement wall. Eventually the technique was developed, tending to level the surface of the wall, to reduce the layer of mortar between the stone blocks and choose the most regular stones in shape and size to facilitate its task.
 When the shape of the segments is adjusted to be more closely matched with the new lower layers interposed Malta, we tend to speak of "work almost reticulated" almost opus reticulatum.

OPUS RETICULATUM.  In the facing walls work camentizia one can notice a gradual trend to stabilize the party to the view through the realization of tufelli of the square base growing.  This is a continuous process in which the final stages can be highlighted, the opus reticulatum, in which the joints between tufelli tend to get in communication with a continuous line form, note, a network. The oldest examples of this technique dates back to the late second century BC.

From the 210 BC was used uncertain work, random length in which the stones were shaped and irregular arrangement; we gradually improved the aesthetic quality of the album, and at the end of this century it joined the work in which almost reticulatum was to be disguised technical realization of small regular tufa stone.  The work actually says opus reticulatum, should be dated to the early 1st century BC.  and had the maximum dissemination and quality of realization in the period of Augustus; it was to produce a work in cement which was a simple surface that is dressed again tufelli of 'squares tuf..cubilias, the truncated pyramidal shape and a square base still remaining in the work fixed in the side Rates cement of the truncated top and disposed in diagonal position, thereby obtaining the feature pattern "network" decorative;  the walls they could then be coated with plastered with lime and medalists putties and marbles, or be left with the stone in sight;  from the moment they found themselves in many wallings opus reticulatum covered with plaster;  encor asks why we make a work so complex and hide with coating;  a reasonable explanation could be that this album was conceived and made to be implemented without coating and only in the following centuries, with the arise of new aesthetic tastes, and when he anchors the previously made structures with such masonry works they were used, the custom of plastering is their decision.


OPUS MIXTUM: born by the union of random length and opus reticulatum.  Already at the end of the Republic began the use it was to strengthen the work reticolata with horizontal bands of brick or cored tiles.  In Imperial Age this use is perfected with the addition of side harps, network speccachiature are so framed brick frames.  This technique is used especially between Flavia age and that of Antonino Pious.  From the time Augustus with the spread of the brick work was perfected reticulatum using horizontal stripes of alternating brick traits opus reticulatum;  it strengthened the structure and it obviated the work's oblique slits problem manifested itself very often.  In the period Flavienne, this technique is refined with the later development of side brick harps.

Opus mixtum (Latin: "Joint work") or vagecum Opus and Opus compositum was a technique of ancient Roman construction. It may consist of a mixture in opus reticulatum and corners and sides of latericium.Il opus may also consist vittatum and opus opus testaceum.L'opus mixtum was used especially during the age of Emperor Adrian


OPUS LATERICIUM or TESTACEUM.  Used from the period of Augustus and throughout the Imperial period is used with great frequency Opus latericium;  it consisted of clay bricks baked in the sun (the opus latericium) and cooked in brick (opus testaceum) and with (opus latericium, makes reference to the two general types of typologies. In Book II discusses the Architectura, Vitruvius wrote that the bricks were to be produced in spring or fall so that they essuyassent with fair speed; wiping too hastily create a moisture differential between the surface and interior which would at break of the brick; further wiping they reduce the volume and they therefore require a maturation of two years The same author defines three types of bricks derived by the Greek architecture didoron, and pentadoron. tetradoron long respectively two, four and five spans, a foot span = 1/4 = about 7.5 cm ,; each measurement was accompanied by long half bricks, so as to have the bricks easily inappropriately to increase strength of the structure.

The sun-baked bricks, also more economic, rather the result without insurance being more prone to aggression of atmospheric agents and the splitting up easily.  The bricks can be triangular in shape to increase the engagement between the curtain and the core cementicium opus, arranging them with the tops of the wall inwardly and casting lead between the two bricks the cement.  Brick could be successively plastered or covered with marbles and putties.  They began thereafter to build buildings that we thought we could stay with the bricks at the sight;  the first large building such was the Trajan Market in the early second century AD. (?) In the second half of the second century AD, (time of Antonians) developed the technique of polychrome brick, obtaining different colorings brick according to the firing temperature and also depending on the quality of the clay used ..


OPUS VITTATUM or LISTATUS.  At the beginning of the IV sec dC it introduced a new type of siding, consisting of horizontal bands of brick alternated with tufa parallelepipeds always arranged in horizontal bands.  The technique that extends forall dry IV is typical in Rome in the time of Constantine and Maxentius. Technical use from the late second century AD.  in which both exterior siding that will dress the core cementicium opus are made with parallelepipedale shaped tufa block of tufelli, cut tufa stone small, alternating with one or more Corsican than bricks

They could be made with walls of an alternation of a single row of bricks and only one queue tufelli also.  To strengthen the structure, they were used as harps side brick on the edges tack, doors and windows.
 The opus vittatum appears at the beginning of the 4th century. apr. AD. and characterizes the time of Maxentius and Constantine. Horizontal beds of bricks alternated with tufa stones (it is a rock formed by the accumulation of volcanic material purposes that tightened in contact with water).


The use of stamped bricks and tiles with a trademark, great help for dating laterizie walls begins very soon, already in dry THE aC.  The stamps were initially elongated rectangular shape, and then to assume, age Flavia, a form that went lunata increasingly become closed until almost circular in the age of Caracalla.  On Adriano becomes mandatory in stamps indicating the consular dates, use hand to hand it diminishes until it disappears at autour164. Between Marco Aurelio Caracalla and they end imperial hand all private factories: since the brick industry became an exclusively national.  Just under a century after the death of Caracalla cease the use of stamps on the bricks that resumes with Diocletian. 


The Romans Floors

Cocciopesto or Signino, opus signinum, Cocciopesto The aggregate is particularly suitable for "waterproof lime malta, so water resistant and time. At Pompeii and Herculaneum, you could get by mixing one part of lime, two parts sand or pozzolan and part of said sand "arena", all enriched with tile pieces and powder terracotta vases reduced to the point of obtaining a perfect material. It was used to waterproof tanks for water , thermal pools, basins and aqueducts to carry floors.

Opus signinum was the type of technique used over the floor from the third century BC.  Until the I century AD. avec with the best broadcast time I delay Republican.  The signino was an economic floor, continuous, waterproof and durable; it allowed a good clean and he reached considerable aesthetic values when taken to be embellished by attractive in cocciopesto layer of woven white and black or polychrome mosaic arranged to form geometric designs creating the paving strips and frames to underscore different residential spaces;  they also got simple decorations spreading irregular shards of marble or white or colored stones, thus obtaining a drawing effect colorful dots;  normally on the reddish background of signino were weaving methods used by pieces of black and white stones to produce geometric illustrations;  the use of colored woven remained limited anyway; ou signinum cards and chips did not cover uniformly the floor, leaving ample visible addresses or signinum signino

The technique began in North Africa, some time before 256 BC.  JC and this is extended in the north to Sicily and finally Italian peninsula.  The signinum floors were found well within the Punic cities of North Africa and generally in the Hellenistic houses on Sicily.  While some sidewalks signinum found in Rome and in the provinces of Campania;  Vitruvius describes the process of putting a floor signinum or mosaic, the trend began in the first century BC. JC,  proliferating in private homes as well as public buildings. In the 2nd century, the album yielded signinum styles more sidewalk patterns.


Opus vermiculatum, was described as Lucilio formed by pieces of marble and colored glass to compose drawings of an extremely suggestive;subsequently, was named Opus Museum came from which is born the word mosaic.  The work of vermiculatum, the vermiculus (from the Latin, the little worm) is an ancient mosaic technique that draws sinuous lines ownership, clean, for the representative drawing.  Small cards used assumed various forms, cubic or numbing, with varying dimensions and also different colors.  This variety of shapes and sizes encor longer allowed to make drawings of great acuity, delicacy. Magnificent examples were found at Pompeii and Herculaneum, or they are spread, deployed and retained the Naples Museum;  but cities even keep all beautiful examples.  The most striking example is in Pompeii Wildlife House or in the exedra leading into the great peristyle found the famous mosaic of the Battle of Arbela between Alexander the Great and Darius, made up of small colorful cards 2 mm of thickness ..


Opus sectile floor was a great value it consisted of thin slices of marble, "crustae" appointed by Plinio and "sectilia" of Vitruvio, of different colors and multiple forms cut to measure and fitted them to realize marquetry marmoreal geometrical designs and complex figurative too; the work required for the realization of such a course was huge floors; specializing in extraction of marble small cards, cutting boards, especially unhealthy work which presented major health hazard for normal quarrying was added having to breathe dust generated by the work of reducing items to get the mosaics cards. Vu le danger , les condamnés criminels ils étaient envoyés. Given the danger, convicted criminals were sent.

Use of signino was learned and installed by Oriental civilizations in the Mediterranean, the first Greek and then Puniciens;  we used a floor with Malta, terracotta and white limestone dust in Greek puniciens buildings Selinunte, before its destruction of 272 BC.  and was therefore adopted by the Greeks of Sicily and Great Greece and the latter technique was learned by the Italic peoples.  The Romans called signino signinum or because the name of the city of Signiae today signs, big producing center famous mainly for the manufacture of tiles.


Opus spicatum Used in paving and rarely in wallings, rectangular bricks were arranged in the spine of fish with intersections between small bricks to ninety degrees. The opus spicatum brick is the type of floor disseminated as imperial age.  The bricks used are small: about 10 cm 2 and a height of 5 centimeters, they have relied on the narrow side that is to say, vertical.


Coatings - walls

The coating has a protective function on the masonry structure in respect to atmospheric agents, sanitary depending on the smoothness wall which allows a better movement of the dust and dirt and typical aesthetic function, beautification the book;  which was used in essence that one that today we call marmorino (breakfast mottled ..) or chews Roman or Venetian saturated by mixing colorful land ,.
 The main layer called "GRASSELLO" compressed marble dust timely and polite, became bright and compact, assuming the sight and touch a very similar appearance to the polished marble.

The added Beeswax has the result of increasing brightness and make it waterproof, coated This already beautiful to begin with, was often painted fees;  this is the same substance used for Renaissance frescoes and enriched with sealants.  This is a coating that breathes and sustainable, respects to conventional coatings based on lime - frieze cement and chalk - crépisse cement.
 Vitruvius in. "De Architectura - Book VII / III", defines the modalities of implementation of the coating using a technique to several layers: it gives are treated in all operations to be performed in preparation for the final part, as it was done in Roman times.

With such a coating procedure resulted strong and durable and the colors glowed more;  in particular by giving the paint on the last layer of sealant when it is not due yet dry, bright color remained long and as washing the wall colors remained intact; indeed lime "deprived of its moisture in the brick and having become porous and dry, is impregnated with any substance with which it comes into contact quickly ... and when it was drying, kneading became a homogeneous block. "When we used a single layer of sand and a single layer of marble dust, it showed burst some because of its thinness." According to Vitruvius ... "The sealant, when well executed, it does not lose the polished messy and it does not lose color when washed either, unless I can not have been given with carelessness or that color has been extended already by being the sealant dry. "

Ch.16 : The Villa of Mysteries...