Window Stools and Sills

For many years, we have produced stone window sills and window stools. Slate window stools are often less expensive than hardwood on an installed basis and hardwood cannot match slate’s durability. Architects specify our materials for their natural beauty, performance characteristics and low maintenance. And because we produce custom sizes and offer several finishes, architects also appreciate the flexibility our materials afford them in their designs.



Window Stools – Custom-fabricated for use in the interior of commercial, academic, public and residential buildings.

Window Sills – Custom-fabricated for use on the exterior of commercial, academic, public and residential buildings.

weathering characteristics

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.


Depends on stone selected. See stones below for available finishes.


Custom sizes for window stools and sills depend on stone selected, finish, thickness, joint width and other factors.


Depends on stone selected, finish, piece size, setting method and other factors. Generally window stools are 3/4″ or 1” thick and window sills are at least 1 1/4” thick.

edge details

We fabricate many different edge details. Exposed edges are usually honed.

joint widths

Depends on stone selected, finish, piece size and other factors.

cost estimates

We are pleased to provide quotations based upon quantity surveys, sketches or architectural drawings.


We are accustomed to working from architectural drawings and we are pleased to produce detailed shop drawings, sketches, templates and shop tickets.

technical support

We are pleased to assist with samples, test data, mock-ups, budget figures, site inspections, stone matching services, guide specifications, technical information, design suggestions and installer and installation recommendations.


Window stools are generally adhered to a substrate and sometimes mechanically anchored as well. Window sills are generally set with mortar and mechanically anchored as well. Contact us for specific sketch details, specifications, recommendations, etc.


Contact us for information regarding the use of sealers, impregnators, oiling, cleaning, etc.