Thomas Jefferson's classical temple-form capitol building, completed in 1788, and added to from 1904 to 1906, has a total of 104 windows. The largest window is approximately five feet wide and 14 feet tall. According to James W. Dossett, architectural conservator with Hillier Architecture, the initial survey indicated that despite peeling paint and ordinary wear and tear, the windows were in good condition and could be restored. The repair process involved several steps.

Decayed sash join will get repaired with epoxy, Virginia State Capitol Photo courtesy of HillierArchitecture

First, the sashes and all hardware were removed on site, tagged with the window number, and then shipped to a restoration shop in Kansas City. Once in the shop, the sashes were stamped with a permanent identification number and sorted. Those needing more substantial repairs were pulled aside.

Then, the sashes were stripped to bare wood. The frames were racked slightly to allow glue to be injected into the mortise and tenon joints. Muntins were routed to receive the thicker laminated glass. Dutchman repairs, a term that applies to cutting out a small area of damaged or decayed material and inserting and gluing a new piece of the same material, were made to large areas of decayed or damaged wood. Epoxy repairs were made for small fills and consolidation of damaged wood. Sanding, priming, spackling, more sanding, and a second priming coat were applied. A finish coat of paint was applied to match the 1906 color, as determined by historic paint analyst Frank Welsh.

Brass sash pulley on left has been partially cleaned, Virginia State Capitol Photo courtesy of HillierArchitecture

All windows were fitted with new laminated low-iron glass, including two layers of one-eighth-inch glass with a clear polyvinyl butyral (PVB) interlayer. The use of insulated glass was rejected because its thickness would have required removing too much of the existing muntins. The laminated glass has better thermal properties than single glazing and is better at reducing sound transmission. Also, the clear plastic interlayer cuts ultraviolet (UV) transmission, which is very important for the maintenance of historic artwork and furnishings. Low iron glass was selected because ordinary glass has a greenish tint.

The sashes were shipped back to the site and re-installed with all new bronze weather-stripping. The wood frames were stripped to bare wood, and repaired prior to repainting. The original wood sills were clad in copper. Probes indicated that the wood was in good condition, and the copper was repaired in place and painted. All hardware was re-used, cleaned and re-furbished. New sash weights were added to compensate for the additional weight of the laminated glass.