Views through a glass block window

We have a glass block window on the south-facing wall of our house. It's the only window on that side, facing the street. According to local building codes, it needs to be a glass-block window because that wall is very close to the property line. It's too close to allow for putting in a standard glass window — one you could see through.

Well, not really too close, we've found out. A couple of years ago, I spoke to our neighbor the mayor of the village about it, and she said she would be glad to give us permission to put in a real window there. Since there's no house on the lot directly across the street, it wouldn't be hard to justify an exception to the rule. Fact is, we kind of like the glass blocks.

A glass block, or brique de verre

When it's sunny, the glass blocks let in a lot of heat. That helps heat up the house when the weather outside isn't especially warm. When it is warm or hot outside, we just open all the other windows and let the heat out. Seldom is it so hot that we feel like we might roast alive. That hasn't really happened since 2003. And even then, it could be that we just weren't used to hot weather again, after living for eight years in cool (I mean chilly), foggy San Francisco.

Through a glass block, blurrily
You can click the picture to see an enlargement.

Truthfully, the glass block window was not in good shape when we moved in eight years ago, and this is the first time we've done anything to improve its appearance. Recently, I scraped and sanded all around inside the window frame, and I used some enduit de lissage — "smoothing putty," a kind of Spackle — to prepare the surfaces for painting.

Two views of the same window — on the left, from below
in the daytime; on the right, from above at night

Then I repainted not just the inside of the frame, but also all the old grout between the blocks. The grout had turned a little black, and there were signs of mildew in the concrete. Before painting it, I washed everything down with a strong bleach solution.

And I didn't worry about "staying in the lines" as I painted. The inside surface of the glass blocks is smooth. Now I just have to scrub off the extra paint. If you look closely, you can see two blocks that I've cleaned as an experiment to see if my plan works. It does. "After" shots to come.