Closing the gap

The attic is insulated. It is now time to think about the wall insulation – or better the preparations needed prior to the wall insulation.

The purpose of the wall insulation is not just to provide thermal resistance, but also seal the building envelope to the point where we have eliminated unwanted air infiltration. A layer of closed cell foam sprayed onto the masonry wall will provide that air seal , filling all small nooks and crevices.

Dealing with the bigger gaps rests on our shoulders. And the biggest gaps are found around the old windows.

window-10 window-11

A couple of windows have most of their window sill missing. The only remaining evidence are some half rotten wood pieces that turn into dust upon touching. All those sills that still were in one piece had their age imprinted in them, similar to the weather and hard work imprinted on the face of an old farmer.


If I think about it, it’s amazing that these sills have lasted 111 years!

We have some experience replacing sills from our work on the 1st floor. There, the window bucks were in good shape, though. Something I can’t say about the 2nd floor windows.


Some moisture induced damage and rot was evident, particularly at the bottom of the buck. That damage was more pronounced on the west facing windows (the weather side) than on the east facing ones.

What to do? My friend Drew made the decision for me, more or less. He clearly was not in the mood to fuss around and strongly recommended to remove the old bucks and replace them. And that is exactly what we did.

Actually, in most cases we were able to save and/or reuse the top plate of the buck. We also used what was left of the old sills as a template to transcribe the notching for the side pieces. This allowed us frame a new buck with the exact same dimensions and in the exact same location.

An important detail, considering that we need to reuse the existing double hung windows until we can afford more efficient replacement windows.

Related posts:

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.