Old Canaan Building Materials

Cedar left entirely alone weathers to silver-grey over two to three years. Bleaching oil accelerates and evens out that process, producing a consistent silver-grey appearance within months rather than years, and correcting the uneven, sometimes blotchy weathering that occurs naturally on shaded or partially sheltered surfaces.

Bleaching oil produces a more uniform silver-grey than natural weathering alone, particularly valuable on elevations with mixed sun exposure where unfinished cedar would otherwise weather unevenly — darker and slower to grey in shaded areas, faster and lighter where exposed to full sun and rain.

Bleaching oil is a thin, semi-transparent oil-based product containing a small amount of pigment (typically grey) along with chemical agents that accelerate the natural greying process of the wood. Cabot and similar manufacturers produce bleaching oil products specifically formulated for cedar and redwood shingles and shakes.

Bleaching oil is typically applied once, shortly after installation, and allowed to work in conjunction with natural weathering thereafter — it accelerates and evens the initial transition but does not require repeated reapplication the way a true stain does. Some products are formulated for reapplication every several years to maintain uniformity.

Bleaching oil is correct where a uniform, immediately consistent silver-grey is the specification — particularly on new construction or additions where matching an existing weathered cedar surface on the rest of the building is the goal, and waiting two to three years for natural weathering to catch up is not acceptable.

From paint and stain suppliers carrying Cabot or similar exterior wood finish lines. Apply to new, unweathered shingles before or shortly after installation for the most even result.