Slate Roofs

Slate is a fine-grained, metamorphic rock that forms under intense heat and pressure underground and is mined. It has a physical characteristic that allows it to be split into thin pieces that resemble roof shingles. Since slate is rock, it is very hard and dense. These physical characteristics make it one of the best natural occurring roofing materials. It is very durable and resistant to the most extreme weather conditions, hot, cold, high wind, hail, and is inherently fire-resistant.

Slate for roofing is sawn into blocks, a little larger than the intended final size. These blocks are split, first in half, in quarters and in eighth pieces, so long as the slate permits. The eight pieces produced are known as a “book”. Each individual piece is known as a “chip”. The chips are squared off and trimmed to the size required. Individually or in stacks, two nail-holes are drilled in each “chip” of slate. The resulting slate roofing pieces come in various sizes and thicknesses, ranging from 3/16" to 2" thick. These pieces are then inspected, counted and stacked on pallets for storage.

Installation of slate is a very specialized operation. It is both an art and a skilled trade. The pre-drilled nail holes in slate accept nails that have to be hit perfectly to stop and hold the slate in place. If hit too hard, the slate shingle cracks, rendering it for use as crushed slate gravel for driveway fill.

Slate can be applied in colors to build very beautiful patterns on steep slope rooftops. Slate can also be repurposed for gravel and other application. Typical colors include Black, gray, green, purple and red. All slate changes color slightly as it ages.

The system has to be installed to the manufacturers installation instructions, the listing, where applicable, and the building code.

Professional Chicagoland Roofing Council contractor craftspeople understand the delicate nailing required to not break slate into pieces while fastening it to stay in place for 50+ years.