Under a good portion of my yard, just a few inches down, are several large expanses of roofing. Plants seem to have no problems thriving around them, but they have to be removed to get to the knotweed roots lurking underneath. When you bend them in half, you get a strong whiff of tar as fresh as the day it was slathered on. Because the trash men don’t take bags that weigh more than 60lbs (especially on days when the trash men are trash women, *grumble*), we have to break these up into 2-foot sections and place each one in its own bag. It’s basically a mini environmental disaster in every way. The only debate is whether the roofing is an older roof from the current house, or from the house that burned down which occupied most of what is now the yard. That will take more research.