At Mount Vernon, we continue traditional roofing practices. Over the years, wood choices might have varied due to availability, and paint types may have changed with new innovations, but painted wood roofs have been in place at Washington's home for almost 300 years. It is natural that all roofs eventually come to the end of their useful lives and need replacement. Over the last three decades, the Preservation Department has looked at these moments as opportunities to return more and more to the materials and techniques known to Washington. In 1996, the Mansion roof was replaced with shingles, hand-split from old-growth cypress logs that had sunk more than a century ago in the swamps of Florida. Similarly, the outbuilding roofs have been replaced with old-growth cypress as they have worn out over the last decade.
Having gone to such lengths to use the same type and quality wood as Washington did, it was decided to give the same thoughtful attention to the paint that helps extend the life of our roofs. At some time in the past, Mount Vernon began using modern paints to achieve its trademark red roofs. Unfortunately, the paint chosen was not robust enough to withstand the harsh effects of weather and sun that a roof paint endures, and the paint began visibly failing within a few years of application, requiring frequent stripping and repainting. In the 18th century, roofs were frequently coated with paints that used linseed oil to bind together the pigments; currently, no such commercially-available linseed oil paints are appropriate to our needs.
As a result, experiments with several formulas were conducted and a commercially-available, oil-based stain that is extremely close to the traditional 18th-century, linseed-oil paint was selected. The full application process is multiyear: two coats in year one, and two coats in year two, for a total of four coats. This stain does not sit on the surface of the shingle, but rather is absorbed, and therefore does not ever peel or require stripping. When the color begins to fade, a new application is made directly over the prior one.