Paul, we used to use roundup on the patio and concrete but we quit a few years ago. Too many cancer causing studies. We switched to a homemade concoction recommended here, white vinegar, lots of water softening salt dissolved and a little water. It is way faster and more effective than roundup and more permanent.
Thanks, yes, I’ve actually used the same concoction on our gravel driveway, not getting too close to the edges as it would kill the lawn / bushes nearby. It’s a lot cheaper than the commercial “long effect” treatments!
But, here I’m basically doing a “pre-planting” treatment: After the weeds are dead / dying, then put in the garden plants. I definitely do NOT want a permanent effect.
I’m not too worried about the Roundup whacking ME as long as I handle it properly. In the course of maintaining our cars (wife’s, daughter, and my car), lots of other “around our place” chores and maintenance, and stuff I work on to make a little money (hopefully), I have to handle far worse...