Hi. I'm wondering if there's a way to add thermal mass to the floors and internal walls of an old wood frame house without adding so much weight that it compromises the structure. Ideally, I'd like to add more low SHGC glass on the south side wall of a Southwest oriented bedroom, with sufficient overhang to block direct summer sun, but realize that doing so without adding sufficient thermal mass won't result in good heat capture in the Winter.

We have a wooden subfloor over an unfinished basement. I've thought about adding tile or brick floors, but from what I've read, a thickness of 4 inches for thermal mass is recommended, and short of using full-size bricks, which would probably put too much strain on the structure, I don't see how this can be accomplished. Any suggestions are welcome. If it's something I can't do, then it's something I can't do, but I thought I'd see what people had to say.

Some background on the house. It's a 900 square foot, 110 year old wooden house, probably once railroad worker housing, about 45 miles North of Denver, Colorado. It has an unfinished basement with a stone foundation. The long side of the house faces East and West (just the wrong orientation for passive solar). The house gets too hot in the Summer and too cold in the Winter. In the Summer the temps can get into the 100's. In the Winter the average temp is 29.

Please note that I plan to better insulate the attic and basement, whether I'm able to implement passive solar design or not. Thanks!