Glossary

Glossary

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Accessories (for roofs)

Complementary pieces for roofing.

Argil

Formed through the disaggregation of feldspar rock that becomes malleable when wet. Argil can be found near riverbeds, often forming banks along the margins. Argil can be white, red, gray and brown. It is composed mostly of hydrated alumina sillicata - - Al2O3 · 2 SiO2 · 2 H2O, has low cristallinity and minute dimensions (particles under 2 µm in diameter). Mineralogically, its main components are quartz, illite, caulinite, anatase, hematite and feldspar.

Break

Same as fracture.

Clay tiles

Products for non-continuous application on inclined roofs and wall linings, made by standardizing processes (extrusion and/ or pressing), drying and baking prepared argil, with or without additives.

Construction products

Products to be used or applied permanently in construction projects.

Coverage

of composing elements (roof tiles and accessories)

Crack

Structural defect that consists of a gap with a more or less regular shape affecting the thickness of the piece and is visible to the naked eye.

Distance between laths or gauge

Length of the exposed part of a roof tile or accessory, measured longitudinally.

Eave

Edge of a roof along the outer part of a protruding roof slope, made of roof tiles

Eaves

Edges of a roof along the outer part of a roof slope, projecting beyond the side of a building and composed of accessory pieces.

Effect of ice

This term refers to the wear caused on roofing pieces by successive frost-defrost cycles.

Engobe

Type of coating, permeable or impermeable, or the material used therefore.

Extrusion

Production process.

Fissure

Crack with a more or less regular shape that does not affect the whole thickness of a piece.

Fixation orifice

Open or easily pierced orifice for the fixation of a product on the support structure.

Fracture

Structural defect that consists on the breaking of a product into two or more fragments.

Garrett

Space under a roof slope

Gutter / Joist

Concave, open piece, usually made of metal, through which liquids run, placed horizontally along the eaves of a roof to drain rainwater, thus avoiding infiltrations.

Hygroscopy

Property of materials relating to their capacity to absorb water. Ceramic materials are less hygroscopic than concrete or mortar.

Lath

Secondary structural piece of a roof arranged in a perpendicular line in relation to the highest inclination of a roof slope, where coating elements are supported.

Linearity

When used in relation to flat or fitting roof tiles, the value of linearity is given by the deviation in a straight line as measured from the roof tile brim, both longitudinally and transversally.
For Canudo roof tiles, linearity is given by the deviation in a straight line as measured along the generating line at the bottom of a roof tile’s concave end.

Mechanical resistance to flexion

This test is conducted by applying an increasing force on a roof tile until it breaks. The value registered at the breaking point indicates the flexion of the roof tile.

Outeiro da Cabeça

Village located 18 Km from Torres Vedras.
The village covers an area of 5,7 Km2 and has a population of 932 inhabitants. Its main economical activities revolve around red clay ceramic industries (roof tiles and bricks) and agriculture.

PDM

 PDM: Municipal Master Plans (Portuguese).

Pre-hole

Fixation orifice that is not fully pierced through.

Recommended overlap

Roof tile length that must be overlapped to the next roof tile.

Roofing functional demands

Minimum criteria to be met by a roof. The proper performance of any roof depends on three main factors: correct conception at the project stage, good individual performance of clay pieces and their correct application on the roof.

Roof slopes

Where joists are placed.

Roof tile fixation

Use of nails, screws, metal hooks or any other auxiliary fixation mechanisms that prevent pieces from moving.

Roof tile gap

Gauge or distance between laths.

Slope

Also known as pitch or roof surface; any flat surface of an inclined roof.

Splinter

Surface defect over 7mm on average, consisting of a fraction of the material, separated from the ceramic body on the visible side of the product.

Support spindle

Relief at the underside of a roof tile or accessory allowing its fixation on the support structure, generally consisting of laths.

Tone

Colour shade variation on the same make of pieces.

Transversal profiles

This term is applied to Canudo roof tiles and refers to the width of its internal edges.

Underside roof tile ventilation

Also known as micro-ventilation; this refers to the circulation of air near the underside of a roof tile. Aids in the drying of absorbed rainwater and eliminating water vapour from inside a building, which could otherwise condensate on the underside of the roof tile; also aids in the conservation of the lath work, when it is made of wood. Improves roof tile resistance to the effect of ice.

Ventilation

Air circulation process.

Watertight

In this context, the term relates to the capacity of a roof to completely prevent the entry of water. Impermeability of the clay material used and total roof coverage must be ensured, as well as the correct inclination of the roof. Wind and rain, which in conjunction can provoke ascending water movement along the roof surface, are a serious challenge to the watertight qualities of a roof.

Technical Support

Concepts

In this first chapter we present some essential concepts: composition, materials and special characteristics, as well as the types of tiles, the types of accessories and the types of roofs and respective terminology.

Composition, materials and special characteristics

Torreense Tiles are produced in Outeiro da Cabeça, Torres Vedras, one of the main clay and ceramic production centres in Portugal, mainly due to the reserves of high-quality argillaceous materials found there.

Our products are produced with raw materials extracted from our own clay pits.

Once retrieved, the argil is allowed to rest for a period of time, thus improving its characteristics.

After the initial phase of homogenizing, the paste is extruded and pressed, shaped into its final form.

Once dried and baked in dryers and ovens finely controlled by innovative computer systems, the end result is a modern product that complies with the most demanding norms and regulations, be they aesthetic - such as colour uniformity - or functional - such as high resistance and low water absorption.

Roof Tile Types

Torrense manufactures the following tile types:

Torreense Lusa Roof Tile

Longitudinal and transversal fitting roof tiles, resulting from the combination of two previously existing roof tile types, the flat “Tegula” and the semi-cylindrical “Imbrex”, and known since its creation in the XIXth century as Lusa or Portuguese roof tile.

Its most striking feature, as is the case with all Lusa tiles, is the dimensional balance between the curved and flat ends, which should be roughly even. This roof tile is homogenous, versatile, easy to apply and highly resistant.

Torreense Marselha Roof Tile

This is a longitudinal and transversal fitting roof tile of French origin. Its origins date back to the XIX century, even though flat tiles have been produced for centuries.

The Marseille tile was quickly adopted throughout Europe, especially in the south. Its use in Portugal is somewhat restricted to specific regions.

The Torreense Marselha tile is flat, easy to apply and provides high coverage per m².

Torreense Canudo Roof Tile

Also known as arab tile, for its origin, or curved tile, for its shape.

The Torreense Canudo tile is known for keeping the profile and dimensions of the traditionally Portuguese Canudo tile.

Its shape and dimension is closely related to the female thigh, reminiscing a time when they were produced manually.

Torreense Milénio Roof Tile

At Torreense we think there is always room for improvement. And with this mindset, Torreense created a whole new type of roof tile.

This is a longitudinal and transversal fitting tile. It is not a Lusa tile as it has no flat end, nor is it a Canudo tile, as it features two curved ends, nor a Marselha tile as it isn’t flat.

It is, first and foremost, a new aesthetic concept with all the advantages of a traditional roof tile and some particular technical characteristics, making it a very special product.

Types of Accessory

Each Toreense tile type places at your disposal a range of accessories to properly begin and finish a roof, complying with all elementary requisites for the construction of a roof. 

The Torreense range of accessories is structured as follows:

  1. Roofing Accessories: elementary pieces necessary for proper roof performance.
  2. Eaves and Eave Accessories: complementary pieces for roofs with eaves.
  3. Mini Pieces: miniature elementary and/ or complementary pieces to improve the aesthetic aspects of a roof.
  4. Decorative Pieces: decorative ceramic elements for roofs.

The range of accessories available varies according to the tile type chosen.

Roof Types and Terminology

There are many types of roof, but most of them are combinations of the following four types:

Shed roof – a one-sided sloping roof.

Gable roof – roof consisting of two intersecting sides defining a ridge.

Hip roof – roof consisting of four intersecting sides defining a ridge and four hips.

Pyramid hip roof – roof consisting of four intersecting sides defining four hips converging at a single point.

The following image shows the position of the main elements of any roof and their usual denomination:

Legend:
1. Field of roof or slope
2. Gable
3. Ridge
4. Hip
5. Valley
6. Eave edge
7. Eaves
8. Gutter

The following image shows the main components of the support structure:

Legend:
1. Triangular roof truss
2. Binding joist
3. Rods
4. Lining
5. Counter-lath
6. Lath
7. Eaves beam
8. Roof beam