Have you checked out the Building Technology Heritage Library?

When it comes to historic preservation weaknesses, I have a few (ie, many). And right up at the top of the list are plan books. These historical publications may have covered contemporary house plans, painting palettes, or more esoteric subjects such as cast iron storefronts. As an example, Sears was going all out during the first half of the 20th century, hawking their “Honor-Bilt” homes in their ubiquitous catalogs.
I love perusing these plan books because they provide great insight on what people were building or using, and can provide good rehabilitation inspiration. So, you can imagine my excitement at being reminded about the Building Technology Heritage Library, the multi-year project from the Association for Preservation Technology to digitize these resources and make them available through the Internet Archive. Now, all you need is an internet connection to review the Sears 1936 catalog (go ahead, see what Sears had to offer here) and literally thousands more. Happy online reading!