The imbrex and tegula were overlapping roof

Roof

A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous....

 tile

Tile

A tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, or even glass. Tiles are generally used for covering roofs, floors, walls, showers, or other objects such as tabletops...

s used in ancient Greek

Architecture of Ancient Greece

The architecture of Ancient Greece is the architecture produced by the Greek-speaking people whose culture flourished on the Greek mainland and Peloponnesus, the Aegean Islands, and in colonies in Asia Minor and Italy for a period from about 900 BC until the 1st century AD, with the earliest...

 and Roman architecture as a waterproof and durable roof covering

Roof construction

This article is about the type of roof construction that consists of footings and an outer weatherproof skin, as found on most domestic architecture....

. They were made predominantly of fired clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

, but also sometimes of marble

Marble

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

, bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 or gilt

Gilding

The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

. In Rome they replaced shingle

Roof shingle

Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat rectangular shapes laid in rows from the bottom edge of the roof up, with each successive higher row overlapping the joints in the row below...

s, and were used on almost every type of structure, from humble outbuildings to grand temples and public facilities.

The tegula (Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 solenes) was a plain flat tile, or a flat tile with raised edges, which was laid flat upon the roof, while the imbrex (Greek kalupter) was a semi-cylindrical roofing tile, like a half-pipe, laid over the joints between the tegulae. When well-made and properly imbricated (overlapped), there was little need for further waterproofing or sealant

Sealant

A sealant may be viscous material that has little or no flow characteristics and stay where they are applied or thin and runny so as to allow it to penetrate the substrate by means of capillary reaction...

.

The roofing area was generally surrounded by Antefixae which were often decorated, and had several decorative anthemion to cover each end row imbrex.

The concept of imbrex and tegula roofing in pitched roof construction is still in use today as an international feature of style and design.

History and development

Imbrices and tegulae were first made by the Greeks

Ancient Greece

Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

. Like brick

Brick

A brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar. It has been regarded as one of the longest lasting and strongest building materials used throughout history.-History:...

s, they were formed of wet clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 in a four-sided mould

Molding (process)

Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....

, often shaped with a piece of wire, and then baked in an oven or kiln

Kiln

A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...

. More sophisticated moulds were developed over time.

Tegulae were originally made perfectly flat, or with nothing more than a ridge underneath the upper border, which allowed the tile to be "hung" upon a sloping roof so that it would not slide to the ground. Later, tegulae were formed with a raised border on the two vertical sides, which would channel rainwater to the bottom of the tile, rather than allowing it to seep between tiles to dampen the roofing materials. Another improvement occurred when these two raised borders were made to converge, forming a broad v-shaped trapezoid

Trapezoid

In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...

 with the narrowest edge downwards, nestling into the widest part of the tile below it to form a continuous channel.

The imbrices completed the waterproofing

Waterproofing

Waterproof or water-resistant describes objects relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or under water to specified depths...

 of the roof by arching over the joints between the vertical edges of the tegulae, dividing the roof into channels. Rain water flowed off the curved imbrices into the channels and down over the surfaces of the tegulae, and descended into the gutter

Gutter

panels of a comic strip or comic book page*Gutter , the space between panes of postage stamps that creates configurations of "gutter pairs" or "gutter blocks"*Gutter, in interface design, the blank spaces that separate rows and columns in screen...

 (canalis). In formal architecture the canalis had a plain or ornamented frontal piece set atop the entablature

Entablature

An entablature refers to the superstructure of moldings and bands which lie horizontally above columns, resting on their capitals. Entablatures are major elements of classical architecture, and are commonly divided into the architrave , the frieze ,...

, immediately above the cornice

Cornice

Cornice molding is generally any horizontal decorative molding that crowns any building or furniture element: the cornice over a door or window, for instance, or the cornice around the edge of a pedestal. A simple cornice may be formed just with a crown molding.The function of the projecting...

. The semicircular opening at the front of the lowermost imbrex was often capped with an ornamental fronton, and the spouts which drained the gutters were frequently decorated with lion

Lion

The lion is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger...

s' heads (capita leonina) or other fantastic or grotesque faces.

By Roman times many tiles were being made under the auspices of various Roman legion

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

s, and were imprinted with a stamp of the legion's insignia

Insignia

Insignia or insigne pl -nia or -nias : a symbol or token of personal power, status or office, or of an official body of government or jurisdiction...

. Imbrices and tegulae are common finds in archaeological site

Archaeological site

An archaeological site is a place in which evidence of past activity is preserved , and which has been, or may be, investigated using the discipline of archaeology and represents a part of the archaeological record.Beyond this, the definition and geographical extent of a 'site' can vary widely,...

s, and their design and markings can be of use in dating the sites and identifying the inhabitants. For instance, a 1993 archaeological dig in Merseyside

Merseyside

Merseyside is a metropolitan county in North West England, with a population of 1,365,900. It encompasses the metropolitan area centred on both banks of the lower reaches of the Mersey Estuary, and comprises five metropolitan boroughs: Knowsley, St Helens, Sefton, Wirral, and the city of Liverpool...

 in England uncovered over 300 kg (661.4 lb) of tile and kiln

Kiln

A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...

 remains. Some of the tegulae were stamped with the "LXXVV" insigniae of the Legio XX Valeria Victrix

Legio XX Valeria Victrix

Legio vigesima Valeria Victrix was a Roman legion, probably raised by Augustus some time after 31 BC. It served in Hispania, Illyricum, and Germania before participating in the invasion of Britannia in 43 AD, where it remained and was active until at least the beginning of the 4th century...

. Romans also often recycled broken tiles by incorporating them into mortar

Mortar (masonry)

Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder...

.

Tiles of marble

Marble

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

 were first used around the year 620 BC

620s BC

-Events and trends:* c. 627 BC—Death of Assurbanipal, king of Assyria; he is succeeded by Assur-etel-ilani.* 626 BC—Nabopolassar revolts against Assyria, founds the Neo-Babylonian Empire....

. Besides the superior beauty and durability of the material, these tiles could be made of a much larger size than those of clay. Consequently, they were used in the construction of the greatest temples, such as the Temple of Zeus

Temple of Zeus

The Temple of Zeus at Olympia was an ancient Greek temple in Olympia, Greece, dedicated to the chief of the gods, Zeus. It was the very model of the fully developed classical Greek temple of the Doric order...

 at Olympia

Olympia, Greece

Olympia , a sanctuary of ancient Greece in Elis, is known for having been the site of the Olympic Games in classical times, comparable in importance to the Pythian Games held in Delphi. Both games were held every Olympiad , the Olympic Games dating back possibly further than 776 BC...

, the Parthenon

Parthenon

The Parthenon is a temple on the Athenian Acropolis, Greece, dedicated to the Greek goddess Athena, whom the people of Athens considered their virgin patron. Its construction began in 447 BC when the Athenian Empire was at the height of its power. It was completed in 438 BC, although...

 at Athens

Athens

Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

, and the Serapeum

Serapeum

A serapeum is a temple or other religious institution dedicated to the syncretic Hellenistic-Egyptian god Serapis, who combined aspects of Osiris and Apis in a humanized form that was accepted by the Ptolemaic Greeks of Alexandria...

 at Puteoli

Pozzuoli

Pozzuoli is a city and comune of the province of Naples, in the Italian region of Campania. It is the main city of the Phlegrean peninsula.-History:Pozzuoli began as the Greek colony of Dicaearchia...

 (modern Pozzuoli). Still more expensive and magnificent tiles were made of bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 and gilt

Gilding

The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

.