Slate stone information Contact


The origin of slate.

Slate stone is formed over a period of hundreds of millions of years through a process of gradual petrifaction of layers of sand and clay. These layers are called slate stone. Naturally the variation in pressure forces will result in slate of varying degrees of hardness and internal structure. The diversity of minerals and metal oxides present in the soil are responsible for the many colour variations and the inherent clay residues can be clearly seen in the stone. The layers are split after extraction, which results in the natural texture of the stone.

Slate Quarry.

Extraction of slate:

Dynamite is used to loosen large blocks of slate along natural fissures, which is subsequently split by hand into large plates and cut to size, either on site or at the factory. Calibration of the cut stone to an even thickness and polishing will round off the process.


Large plates are loosened by hand.


Tiles are available in the following sizes:

Square: 60x60cm, 50x50cm
40x40cm, 30x30cm
Rectangular: 60x40cm, 60x30cm
40x30
Hand cut tiles: 255x355mm, 220x280mm

Random: Tiles with a fixed width of
30cm and variable length
Roman pattern: 4 St. 20x20
2St. 20x40
4St. 40x40
2St. 40x60
More options possible!
Grazy Paving or Flagstone: Slate stone uncut, as extracted.


Thickness variation in slate:

Slate is not sawn, but rather split along the naturally formed layers which results in the characteristic slate stone surface. This process does, however, cause the plates and the tiles to vary in thickness between 0,8 to 2,5 cm. A uniform thickness can be obtained by calibrating the plates with a calibration machine (normally 12mm).

This has more benefits:
 * Gluing of the tiles is now possible.
 * Application is faster and simpler, therefore more cost effective.
 * Lower application heights.
 * Subsequent application over existing tiles may be possible in some cases.

Technical characteristics of slate stone

 * DIN norms are applicable to the various slate stones.
 * Exceptional lifespan (on average 40 years).
 * Colours are timeless and not sensitive to fashion trends.
 * Suitable for floor heating - retains heat well.
 * Relatively easy maintenance.
 * High ware- and acid resistant.

Slate: in and around your home:

By using slate in your home you can create an atmosphere of rest, warmth and style. It combines exceptionally well with a diversity of trends and cultures. As with other natural products such as wood and leather, slate combines effortlessly with a multiplicity of styles. Slate is mainly used for floors: in entrance halls, lounges and kitchens, or on staircases as an eye catcher. It is also excellent for paving around fishponds, on terraces, driveways, garden paths and patios. It is also used as cladding on walls, as well as roof covering. On an English-style home, for example, a slate roof will create the perfect ambience. For this purpose African slate, in particular, may be the appropriate application, as it will distinguish itself from others by its rugged exterior. A relatively unknown application is a slate stone finish on the exterior walls of a house or building. The visual effect of this natural finish can be quite stunning.

Flooring: Some details to consider:

Some important factors must be taken in consideration when applying slate to floors, as the floor will comprise a number of layers which has to bond properly with one another. Only then will a floor be created which will stand the test of time and guarantee years of living pleasure.

Examples of floor construction:

Slate in mortar on raw concrete floor. 35-50 mm building height.
Slate glued onto a smoothed, level screed. 15-30 mm building height.
Slate in mortar with under floor heating. 55-75 mm building height.
Slate in mortar with under floor heating lain on insulation, which in turn is laid onto a level screed. 65-110 mm building height.
Slate glued onto a smoothed, level screed together with electrical under floor heating. 20-30 mm building height.

Under floor heating.

LSlate combines very well with either electrical- or water-sourced under floor heating. Electrical heating has a number of advantages over water heating, e.g. the negligible floor height, evenly spread heating area and short warming-up period. Conversely, water heating is cheaper, both in purchase price as well as usage. When water is used for heating, care should be taken that the supply is not laid too far apart, which may result in "zebra lines" of warm and cold strips in the floor. With slate floors in particular, it is recommended that heating is kept at a regulated temperature to prevent over-heating.

Warning!

Under-floor heating under slate floors must not be activated for at least three months after installation, to allow for proper bonding and settling of the slate tiles. Commence heating at the minimum temperature on the first day, thereafter increasing the heat with one degree per day until the desired temperature is reached.

Flexible joint

Floors expand and contract during temperature changes, especially in the case of under floor heating. Depending on the shape and size of the room, it may be necessary to insert one or more flexible joints to allow for such movements in the floor. (E.g. large or L-shaped rooms). A technician will be able to determine how such a joint, if required, can be applied to best advantage. It follows that any joints in the bottom layer of the floor should be replicated in the upper (slate) floor. Furthermore, the slate floor must be installed free of any surrounded edges or columns. It can then be stylishly finished with a suitable slate plinth.

Joints.

Slate tiles can be laid with narrow joints so as to form a beautiful, almost solid looking slab. However, this is not always possible due to possible variations in the angularity, sizes and height of the tiles. Also, a too narrow joint may cause improper bonding of the glue. The width of the joints between the tiles serves to absorb the aforementioned variations and a too narrow joint will nullify this absorption. It is therefore recommended that a wider joint is applied with slate floors.