[BCMA] Window Glass Replacement

Tue Apr 9 00:42:31 PDT 2019

Hello Juliana

I would strongly recommend against replacing the single glazed historic
glass in your storm windows with double glazing. I suspect that most of the
existing glass is original to the wood sash and storms. The glass, which is
likely somewhat wavy and figurative, is along with the sash, the window
jambs, the trim and the storms themselves a significant character defining
element of the building. 

1.	Conserve the heritage value of a historic place. Do not remove,
replace or substantially alter its intact or repairable character-defining
elements.

>From the Standards & Guidelines for the Conservation of Historic Places in
Canada.

Modern float glass has virtually no interesting imperfections and is for all
intents and purposes  “dead” compared to the pre 1950’s extruded glass which
would have been used in your 1920’s windows and 1940’s? storms. In addition,
thermal glazed (double) units are of a significantly thicker depth and would
require the storm window sash rebates to be routed out to accommodate the
extra thickness. This weakens and irrevocably changes the look of the sash.
The storm windows are likely ¾” – 1” maximum in depth.

You can accomplish the same or better heat retention by renewing the window
putty where required on both the double hung sash and storms and by
improving or including weather stripping between the vertical rails of the
double hung sash and the jamb as well as the between the lock rails of the
upper and lower sash and between the bottom rail and the sill. Any double
hung sash that are to be permanently fixed shut can be caulked to prevent
air leakage. The storms can also be weather stripped or caulked (if
permanently fixed) but a small gap between the bottom rail and the sill
should be left open to allow moist air to escape in order to prevent the
double hung windows from constantly fogging up and causing eventual damage.
I can’t tell from the picture, but if the 3 vent holes in the storm sash do
not have a flap installed on the inside face to close them off this can be
added to cut excess air flow during the cold season.

Happy to discuss further.

Regards

Davyd 

(restoration carpenter)

Davyd McMinn

President

Ross Bay Villa Society

 <http://www.rossbayvilla.org/> www.rossbayvilla.org

 <mailto:info at rossbayvilla.org> info at rossbayvilla.org

 <http://www.facebook.com/rossbayvilla> www.facebook.com/rossbayvilla 

From: bcma-bounces at lists.vifa.ca <bcma-bounces at lists.vifa.ca> On Behalf Of
Moderated BCMA subscriber listserv.
Sent: 02 April 2019 12:02
To: bcma at lists.vifa.ca
Subject: [BCMA] Window Glass Replacement

Hi everyone,

We are currently planning a project to restore the windows of the 1924
heritage building that houses our museum. Our goal is to both stabilize the
windows and to stop heat loss in the winter. While we plan to preserve as
much original material as possible, some components, including the glass of
some windows, will be replaced. 

The building has storm windows that were likely added in the 1940s, and we
plan to leave them on permanently. We’ve been asked whether we want to
replace the storm window glass with double glazed panes during the project.
Any thoughts on the replacement of glass for a heritage building? Would
replacement of the storm window glass affect color and appearance from the
outside? Should it be avoided?

Any advice would be appreciated. 

Thank you in advance.

Sincerely,

Julianna Weisgarber

Executive Director

Oliver and District Heritage Society Museum and Archives

 <http://www.oliverheritage.ca/> www.oliverheritage.ca l 250.498.4027 l 430
Fairview Rd, Oliver BC 

I acknowledge that my work place is within the unceded ancestral and
traditional territory of the S’yilx-Okanagan Nation.

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