What is the best quality slate?
Welsh slate is considered by many as the best natural slate in the world. Welsh slate is available in either heather (purple) or blue-grey. Penrhyn slate has a beautiful soft blue/purple appearance and can be expected to last more than 100 years.
Are there different grades of slate?
Slate is graded according to ASTM standards as S1, S2 or S3, with S1 being the highest grade. Slate grade S1 has a minimum lifespan of more than 75 years. S2 is rated for 40 to 75 years. S3 is rated for 20 to 40 years.
How do I know if my slate is soft or hard?
(There are some black slates that are hard, and there are some colored slates that are soft because they're really black slates that have been faded by the sun.) In any case, he said, a slate expert -- known as a ''slater'' -- will be able to tell hard slate from soft simply by tapping on it.
Unlike many roofing materials, slate tiles are completely fireproof. Weather resistance is another reason slate roofs are worth the investment. They are waterproof as well as resistant to severe weather and perfect for colder climates. Slate roofs can withstand high winds, heavy snow, and rain.
I have been advised to go for a limecrete subfloor, as this will allow the floor to breathe and avoid damp being pushed out to the walls and causing a problem. However, I suspect that slate, particularly sealed slate, is not breathable, which might make a limecrete floor an expensive and unnecessary option.
Spain is the world's biggest producer of slate, one company alone accounting for a quarter of the world's supply with 16 quarries and 22 processing plants. Spanish slate can vary tremendously in quality.
Slate is a natural material with unmatched technical features that will last well over 100 years. In fact, it's usually the fixings and the supporting timbers that deteriorate before the slate tiles themselves.
UV radiation and moisture also cause lime and other mineral salts in slate to break down. This causes slate to become more porous. These minerals are eventually deposited as white powder on the surface of the slate, and this is called efflorescence.
The longevity of slate is key to its value in the eyes of homeowners. After all, roofing can be expensive. Slate is one of the few roofing options that doesn't need to be replaced within the span of a lifetime. In most environments, slate shingles will last at least 125 years and sometimes as long as 200 years.
Slate is a metamorphic rock with a dull luster. The most common color of slate is gray, but it can also be brown, green, purple, or blue. Slate is formed when a sedimentary rock (shale, mudstone, or basalt) is compressed. Over time, slate may transition into other metamorphic rocks, such as phyllite or schist.
The minerals inside slate is what determines its colour. In slates that appear green, this is due to chlorite – a group of common sheet silicate minerals that form during the early stages of metamorphism. They most often form in rock environments where minerals are altered by heat, pressure and chemical activity.
When it comes to value, Architectural Grade is the most selected, measuring between 3/8″ and 1/2″ thick.
There are three main variations of colour, the most common being blue / grey but Welsh slate also comes in a purple hue as well. The soft purple coloured slates are referred to as 'Heather' and the brighter, more pink coloured slates are known as 'Blush'.
What is Natural Slate Rust? Rust is a phenomenon when some pyrite compounds react with water to produce a rusty coloured stain. Metal inclusions in natural slate can lead to rust, but not always.
– Welsh slate due to its age, is much denser which means it's a lot stronger and durable than Spanish slate. Spanish slate is still durable but will discolour and degrade faster than Welsh Slate.
The Chinese slate used by Nulok is extracted from a large deposit at the foot of the Lushan Mountains, where the unique geographical location and atmospheric pressure in the area makes the slate finely grained. The life span of Chinese slate from this area is at least 75 years.
Colored slate is never fading. However, it may weather with time due to the oxidation of it's embedded minerals. This causes the color of the tile to change over time, often towards buff, brown, gray or tan tones.
Slate tiles may be punctured, cracked or broken by hail. Any of these conditions could be deemed functional damage if the damage is serious enough. Because slate is a sedimentary stone composed of layers, hail damage may appear as a slate with a portion of layers missing.
Installed properly, slate roofs require relatively little maintenance and will last 60 to 125 years or longer depending on the type of slate employed, roof configuration, and the geographical location of the property. Some slates have been known to last over 200 years.
The average cost to repair a slate roof is about $1,680, with a range between $704 and $2,661. Small repairs like replacing individual shingles may cost as little as $250, but restoring a major portion can cost up to $5,000. A new slate roof costs over $10,000 to install, so even major repairs are usually worthwhile.
|Material Type||Life Expectancy|
|Fibre Cement Slate / Man Made Slate||50-60 years minimum|
Even in the face of the unpredictable British weather, Spanish roof slates have performed well for hundreds of years dating back to the 1300s. Good quality slate is known to last atleast 70-80 years on a roof, while others insist that Spanish slate can last the life of the building it serves if laid correctly.
Counter battens are needed when sarking or plywood boarding is installed directly onto rafters, except in situations where slates are nailed directly into timber sarking. At the eaves, insulation can be pushed up to the underside of the Permo® underlay.
Slate is considered to be in between 2.5 to 4 on this scale in terms of hardness, which means that it is, on average, almost as hard as marble and limestone, but not as hard as granite or natural quartz.
The major slate mining region in the United Kingdom is Wales; in Cornwall there are a number of slate quarries (famously the village of Delabole), and in the Lake District there are numerous slate mines and quarries.
It is well known that clay, concrete roof tiles and good quality natural slates can have an incredibly long lifespan. This means that during a demolition or a re-roof, the slates and roof tiles can be salvaged and re-used, either on the same property or, more commonly on another project.
However, slate roofs need repairs less frequently than other types of roof, and it's easy to remove individual slate tiles and replace them. When doing this, it's actually recommended to use older, reclaimed slate taken from other properties, as it will be thinner than new slate.
This makes slate smooth and sleek, as well as impermeable to water. Slate is commonly grey, but can also be black, green, purple, brown, or brick red. A mottled, rusty tone on the surface of some slates is caused by groundwater that percolated along the natural seams in the rock, oxidizing the minerals along the way.
Here are some common methods used to repair slate roofs employed by roofers (non slate roofers): copper hanger. roof cement. face nailing w/caulk or roof cement. caulk.
By other sources, Vermont slates have life expectancy of 100-200 years.
To remove moss as well as mould or rust, gently scrub with a medium-stuff brush and a mix of suitable roof slate cleaning products, such as household cleaner and water. High pressure water including from pressure washers can break apart slate, particularly older or damaged tiles.
Slate is hard-wearing and durable but it can easily crack under pressure. That's why professionals use hook ladders, jacks and planks on slate roofing. This allows them to walk on the roof without putting any weight on it. If you don't have the proper materials on hand, it's best to let a professional tend to the roof.