History of Windows in America1620 - 1950 :History of Windows in America1620 - 1950


Window Construction 1600s :Earliest windows in America were casements. John Balch house cir 1636 Beverly, MA one of the oldest in New England Window Construction 1600s Note the diamond glass leaded windows


Slide 3:By the 1620s window glass was available in America as a result of English imports, although earlier attempts had been made to manufacture glass domestically. Earliest windows were made locally by hand, frequently on site.


Early Window Construction :Window construction in America lagged behind that of Europe. Early American glass types were Crown and Cylinder glass Early Window Construction


Crown Glass :Crown glass was spun into large circular pieces called a table This type tended to produce concentric ripples in the finished glass. The bump where blow pipe was connected resulted in the Bull’s Eye typically used in transom over doors Crown Glass


Crown Glass Process :Crown Glass Process


Early windows :Early windows Early pane sizes were small such as 6x8 or 7x9. Glass was expensive and difficult to make in large sizes.


Cylinder Glass :Was blown in cylinders, the ends cut off then split. It was reheated, spread flat and cut to desired size. Cylinder glass tended to have parallel marks and small air bubbles Less waste then crown and larger panes possible. Cylinder Glass


Cylinder Glass Process :Cylinder Glass Process


1920s – Plate Glass :Around 1920, plate glass was considered the latest in sheet glass making. After the glass has been melted in a pot, the latter is taken bodily from the furnace, and the glass poured on to the rolling table, about 28 feet x 16 feet. This consists of a large cast-iron bed, usually made up in segments, carefully bolted together so as to give an even smooth surface and cooled by a water circulating system. A large roller extending the full width of the table, and weighing from 5 to 6 tons, is mechanically driven forward and spreads the glass out into a sheet. 1920s – Plate Glass


Pilkington Float Glass :Float glass involves a ribbon of glass moving on rollers from a furnace at 1,000 C and floating along the surface of a bath of molten tin. The surface of the tin is completely flat and so the bottom glass surface as well as the top surface is also flat. The ribbon is then cooled and passed through an annealing oven. The result is glass of uniform thickness and with a bright, fire-polished surface. The process is cheap and effective, particularly as it is a continuous surface, and variations in the width of the glass can easily be carried out. Pilkington Float Glass


Window Sash Structure :Window Sash Structure


Joinery detail :Joinery detail


Slide 14:1785 - Weare, NH


Slide 15:1800 CapeWonalancet, NH


Original 9 over 6 restored in 2006 :Original 9 over 6 restored in 2006


Is Restoration Green? :What is the impact of restoration vs. replacement? Is it sustainable? What are the long term cost/benefits? Is cost the primary factor? Is Restoration Green?


Preservation is Green :Preservation is Green