#155 is a huge improvement over prior iterations. I liked #133 but something about it was too dark, and you nailed it by changing the windows. A couple tweaks if you have time: 1) can the font be darkened a bit similar to #133 and 2) can "construction services" be the type below "Element"?
I agree that it would be ideal if the logo illustrated our industry, but I think a semi-related or theme/concept logo could also work as the primary function of the logo is to be recognizable/unique/memorable. 99% of our advertising is through word of mouth and our contacts, so we probably won't be using the logo to advertise, if we do much advertising at all.
That being said, I can definitely see the benefits of having the logo be a more literal representation. It will come in handy down the road as we expand. We're not going to sit back and rely on the same set of accounts to survive. And #155 is the best industry-related logo we've seen. This has become a very difficult decision.