Top/Bottom Sidebars only half width

I’ve read every post I can find about this issue, and the only real solution I found was to make sure that the widgets are in the top or bottom sidebar. The problem is that this still doesn’t make the widgets go full width for me. They are all half width, as if it’s a two columns sidebar. I reset everything to default settings and even removed and replaced all the widgets, but the issue persists. My front page is set to my latest posts. Should it be a static page? I’ve been messing with things for hours. Please help.