Bleaching Oil for Cedar Siding

I was on a job site the other day and we were reviewing the transformation that occurs when you add a bleaching oil and stain to cedar siding. The contractor had built a sample wall and we were discussing the process. He indicated that the siding would be stained, and then stained again six weeks later. I said I didn’t remember that being the way it should go, so I checked with the manufacturer, Cabot, and found that re-staining is not recommended, and can cause other problems, such as cracking and uneven colors.

After the siding is put up, it should be cleaned with “Problem Solver Wood Cleaner“(also made by Cabot), so that any bacteria or mold that may have accumulated while the cedar was stacked up in storage can be destroyed.  Once the wood has dried, the stain is applied. The stain colors and seals the wood and will allow it to age gracefully in a uniform shade. It will take a good amount of time (a few months) for the stain to settle into its long-term appearance.  Some stains are clear, some are tinted.  In either case, the stain needs to be continuously stirred to ensure that the application has the desired effect. Anything less than complete agitation levels will result in a diluted and uneven finish.

Bleaching oil is a unique stain. It includes a grey stain within the mix. The color gives the cedar a color similar to what it will ultimately become. The rest of the mix is made of chemicals that accelerate the natural weathering of the wood toward its ultimate driftwood color, the color it would become if left untreated but out in the weather and sunshine. The initial stain fades away and the bleaching takes over in about six months.In theory, once bleached, cedar shingle siding will need no future treatment. In reality, it will need some occasional touching up, particularly on the north side of the house where mildew is prone to grow. But regardless of that, bleaching oil on cedar shingles is the authentic way to get the look of the Shingle Style houses of the New England coastline and the mansions of the Hamptons.