Grading Roof Slates

This slate is split at thicknesses between 1 4 to 3 8.

Grading roof slates.

Us manufactured inspire slate suitable for pitches as low as 14 degrees. There is a recent trend to load crates directly on to the scaffold and lay the slates straight out of the pallet without grading. Slates should always be diligently sorted into three or four groups of equal thickness. If the slate has been sorted and the roof marked out properly then laying the slate is straight forward.

Standard grade rough texture. However the recent trend is to forklift a pallet on to the scaffold and lay the slates straight out of the pallet without grading. The astm standards for slate are some what regulated by members of the national slate association nsa with. For further information on cupa s classification please read our guide to the grading of natural slate roof tiles.

Slates come in all shapes and sizes. Read on for an understanding of cupa s natural slate tile selections and a guide to the natural slate grading on site. They grade slate thickness into three groups thin medium thick using the thinner slates at the top of the roof and thicker slates near the eaves. This shouldn t be confused with the need for slate grading on site.

When choosing the right slate for your roof the higher the selection the more uniform the finished roof and the fewer imperfections. Check roof pitch and make sure that the correct size slate and lap are used. Astm roofing slate grading explained. The process of sorting and grading used roofing slates ensures that they can be installed effectively.

The categories to choose from are r excellence h and natural. Second hand slates will usually need to be sorted and graded prior to being installed on a roof. The american society for testing and materials astm is a free acting society with the goal of keeping a high national standard for materials. Foliation may not correspond to the original sedimentary layering but instead is in planes perpendicular to the direction of metamorphic compression.

How does astm requirments apply to roofing slate. Slate is a fine grained foliated homogeneous metamorphic rock derived from an original shale type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism it is the finest grained foliated metamorphic rock. The best slaters will carefully grade every slate before it goes on the roof. It has the surface appearance of heavy grade in a.

Grading roof slates flatter roofs. With its enhanced grain it is an unmistakable slate roof with an expected usage of over 150 years. It is extremely unlikely to.