Natural slate roofing enriches the overall appeal of a building while affording more lasting and reliable protection than any substitute. Architects specify our own Vermont roofing slates for their unfading and weathering colors, durability, ‘on-the-grain’ fabrication and high quality standards. And because we produce slate roofing tiles in custom sizes, shapes and thickness, architects also appreciate the flexibility our materials afford them in their designs. Our domestic slates have been widely used for roofing since the early 1800s. A slate roof is an excellent choice for both new construction and historic restoration.
Many styles of roof are available including uniform lengths and widths, uniform lengths and random widths, graduated lengths and/or thickness, textured roofs, patterned roofs and staggered butts.
We offer copper slater’s nails, stainless steel slate hooks, slate rippers, slate hammers and slate cutters.
Some materials are “unfading”, meaning they will hold their basic color even after many years of exterior use. Others are “weathering” or “semi-weathering”, meaning they will change color (usually to shades of brown) when used outside. A stone’s weathering characteristic is primarily an aesthetic consideration. “Weathering” in and of itself does not adversely affect the performance or durability of a stone. See stones below for weathering characteristics.
Our slates have tested ASTM Grade S-1 (highest), are durable (lasting over 75 years), exceptionally strong and hard, have low absorption rates, are dense, acid- and heat-resistant, extremely resistant to freeze-thaw cycles and fireproof.
Natural Cleft with trimmed edges.
Standard lengths from 12 to 20 inches. Standard widths from 6 to 14 inches. Custom sizes depend on stone selected, thickness, and other factors. Custom shapes also available.
Standard thickness is 3/16-1/4 inch. Other common thicknesses include1/4” minimum, 3/8”, 1/2”, 3/4”, and 1”. Custom thicknesses are available.
A function of shingle length and headlap. Exposure = (length of shingle minus headlap) divided by 2.
We generally put the nail holes in the slates at the quarry.
We are pleased to provide quotations based upon quantity surveys, sketches or architectural drawings.
A function of the pitch of the roof. Standard headlap is 3 inches.
We are accustomed to working from architectural drawings. Our in-house drafting department is pleased to produce estimates, detailed roof drawings and sketches.
We are pleased to assist with samples, slate matching services, site inspections, mock-ups, installer recommendations, test data, specifications, technical information and design suggestions.
Generally installed with copper slater’s nails or stainless steel hooks. Contact us for specific sketch details, specifications, recommendations, etc.
Minimal. Broken shingles can be easily replaced with the use of a slate ripper.
We strongly suggest the seminal work on the subject entitled Slate Roofs, originally published by the National Slate Association in 1926 (not much has changed). A must-have book loaded with photos, sketches, installation details, information on specific slates, etc. Contact us to purchase this book.
It is well-documented that for maximum strength certain strong-grained roofing slates must be produced “on the grain”. This means the long dimension of a piece of roofing slate must run parallel to the grain. “Cross-grained” or “diagonally-grained” roofing slate is significantly weaker than properly fabricated shingles. Slate is like wood in this respect. Imagine the weakness of a cross-grained wooden rafter.
All of our quarrying and fabrication techniques have been designed to produce slate that is “on the grain”. Although this centuries-old method causes us to have higher labor costs and waste factors than companies that produce roofing slate with no regard to grain direction, it results in a better product and significantly less breakage on the jobsite.
As shown below, our slate splits in two directions: 1) along its cleave into layers, and, 2) along its grain. The grain cannot be seen (as opposed to the cleft pattern) and runs in a single direction perpendicular to the cleave. Once a shingle has been produced, it is only possible to determine the grain direction by breaking the piece.
When the blocks of slate are brought to the splitting shed, they’re first crosscut against the grain with a diamond wetsaw. The crosscut blocks are then sculpted, or split along the grain, with hammer and chisel. These blocks are split into smaller blocks which are then halved again and again to produce rough shingles. The rough shingles are then mechanically trimmed and punched or drilled to produce the finished product.
There are two issues to consider when specifying roofing slate: