Differences in Natural Slates

What Is Natural Slate?

Natural slate is metamorphic rock that is composed of alumina and silica for large-scale use in construction projects such as flooring, roofing, and walls.  In short, this material is laminated rock and is available in multiple different forms, but slate tile allows the most creativity because of its various available shapes.  These tiles can also be custom made in various shapes, colors, textures, and finishes.

Slate slabs are very broad pieces of material that can be used for artifacts in the living room, kitchen, or garden.  The cleavage on natural slate slabs is not pronounced, and those that are produced can make various items such as gravestones, mortuary slabs, and snooker tables.  These can also be custom built for specific projects and come in a variety of dimensions and finishes.

Natural slate strips are long and narrow with a uniform width.  Providing a rustic appearance and great performance, this stone has emerged onto the construction scene.  Slate strips are manufactured from natural slate stone and are cut into pieces to match a particular project.  These come in multiple colors and dimensions and can be used for walls, roofing, and flooring to make various designs.  (See http://www.slate-stone.com/ )

Benefits Of Slate

The beauty of natural slate is unchallenged.  Some of the benefits of using natural slate for roofing include appearance, durability, and energy conservation.  Other, lesser known, benefits of natural slate are that it is fireproof and waterproof.  Investment is permanent which means it increases property value and requires no maintenance; it resists seasonal climate changes, and fungus and mold are not a factor with natural slate.  Natural slate is also LEED certified, green recyclable, environmentally friendly, requires minimum repairs, easy maintenance, high re-sale value, and good salvage value, and provides loan and insurance advantages.  (See http://www.greenstoneslate.com/benefits.htm )

Slate For Flooring And Roofing

Natural slates have been used for flooring throughout centuries because they are essentially slip resistant.  They also resist stains because they are non-absorbent, which in turn is protection against mold and algae.  Slate has been known as the ultimate roofing material because it can be produced in uniform thickness and is very durable.

It has been estimated that Pennsylvania slate will last 60 years; Vermont and New York slate will last 125 years, and Virginia slate will last 175 years.  A Virginia natural slate roof will cost about $2.14 per square, per year.  Today, natural slate costs $400-$500 per square.

About Natural Slate

Natural slate in the United States is readily available for any project.  Natural slate roofing comes from many different sources, while most slate companies have their own quarry.  Only a handful of companies import natural slate from around the world; however, natural slate is quickly becoming a global market.  Slate quarries generally produce 50 – 100 squares or 1 – 2 truckloads a month, but there are smaller companies in Europe that are capable of producing an equivalent of 72 truckloads a week which is 180,000 up to 200,000 squares a year.

The weight of natural slate varies, but on average it is 8 to 10 pounds per foot, which is 800 to 1,000 pounds per square.  The weight will vary due to the density of the material.  Common slate sizes, measured in inches, are 12,14,16,18, 20, 22, and 24.  Keep in mind that the width of the slate is never less than half the length.  Standard natural slate means that the slate is the same size in both length and width.  Random natural slate has the same length, but the widths will vary.  (See http://www.sacredplaces.org/
PSP-InfoClearingHouse/articles/Slate%20vs%
20Asphalt%20Comparing%20the%20Alternatives.htm )

How Is Slate Produced?

Because slate is a natural material occurring from the earth, it is only found in select places.  To extract it from the ground, the material is drilled, blasted, and then sawed.  It is removed from quarries in large slabs, so they can produce a variety of products.  The natural slate slabs are then cut into thick blocks, which are then split by hand, down to chips.  The chips are then trimmed to a specific size, punched into beveled edges, and then shipped throughout the world.  Natural slate is sold through both distribution and directly to the owner or contractor.  The domestic supply of slate in the U.S. has been historically low, but recent years have seen major increases.

All About Granite

Granite can be used in similar projects just as slate; however, it still has its own properties.  Granite is a common, widely occurring group of intrusive igneous rocks that form at large depths and great pressure beneath continents.  Today, granite makes up 95% of the earth's crust.  Granite is created through the cooling process of magma and lava that are found in the earth's core.

The texture of the granite depends on its grain size.  Granite counter tops have become commonplace in the U.S.  The cost of granite is usually between $40 per square foot and the highest a budget allows.  It is a myth that granite is expensive.  It is available in many colors and is very durable.  Like slate, granite is also fireproof and waterproof.  This material provides an appearance of heavy crystalline and mineral grains.

Granite, unlike slate, will stain because it is porous.  Anorthosite is known as black granite and has a completely different composition than regular granite.  Granite ranks a 7 on the hardness scale, and because of this it is easy to maintain.  There are more than 16,000 types of granite from throughout the world.  This material is also resistant to caustic chemicals and is not affected by climate or temperature chances.

The four main minerals that are found in granite include feldspar, quartz, hornblende, and mica.  The three main varieties of granite are Biotite granite, Hornblende granite, and Tourmaline granite.  Biotite granite, however, is the most popular form used for construction and building projects because of its durability.  After the granite has been processed, it is then cut into thin slabs by multi-blade gang saws.  The use of steel abrasive tools provides the granite with smoother edges.  (See http://www.minerals-n-more.com/Granite_Info.html )