Methods of Work: Building Historic Window Sash

Methods of Work: Building Historic Window Sash

This following blog post is one of an occasional series of reports and perspectives on work taking place at the Anna Clapp Harris Smith House in Dorchester through Handmade Houses, a partnership of Historic Boston Incorporated and North Bennet Street School. The collaboration preserves at risk colonial and early 19th century buildings in Boston while providing preservation carpentry students with hands on training and experience. Begun in 2010, the partnership?s work is supported by a discrete revolving investment fund established through the generosity of The 1772 Foundation.

Building Historic Windows
by Bill Rainford, North Bennet Street School of Preservation Carpentry, class of 2011.

Period appropriate windows often allow you to peer into the soul of a classical house. When working with historic properties, especially earlier homes, it?s rare to come across original windows. Windows take a lot of abuse from day to day use, exposure to the elements and changes in style and building materials over time. As time marches on, old windows are often ripped out wholesale and replaced, all too often with inferior aluminum or vinyl replacement windows.

Occasionally we get lucky and find an original window in the back of a house, up in an attic, enclosed in a wall or documented in another manner ? say through historical photographs, diaries or documents. Historical documentation and evidence at the 1804 Anna Clapp Harris Smith House have led us to the decision to restore the front windows back to the 12 over 12 divided light window sashes.

In our modern world we often take for granted windows as just something you buy in a store and have installed. But if you?ve ever looked closely at an historical window that has survived the test of time you?ll see a lot of what helped it last so long. Good materials, solid joinery, good quality glass, glazing points, quality glazing applied well, paint that was maintained are all the hallmarks of a quality window.

In order to reproduce a window that lives up to or exceeds historical precedent, much work goes into a window sash made with period appropriate tools, techniques and materials. Machines can help with some of the stock preparation and running some molding profiles, but there is no replacement for a skilled hand and a sharp tool.

The Process:

? It all starts with good planning. Deciding what can be saved, what needs to be replaced.
? Make a detailed drafted plan and/or story stick

? From the above work out your materials list
? Purchase Quality Heartwood
? Mill your stock and plane it by hand
? Run your molding profile(s)

? Cut the joinery for your sash rails and stiles

? Cope your joints and test fit

? Cut your muntin bars and cope and fit them as well

? Make your pin stock

? Draw bore your through joints

? Set your glass

? Glaze the window
? Paint the window
? Install the window

And now enjoy the window with a view and longevity similar to what the original occupants of this home would have seen.