Hi all, new to the forum but hoping to get some good information from here. I've been a homeowner for about a year after living in military housing for 13 years. Definitely a change.

Anyway, my particular question is this, with a little background: My house is a 1967, built on slab, in CaliforniaName:  Toilet flange.jpg
Views: 1233
Size:  63.8 KB. I'm remodeling both downstairs bathrooms and have completed one without problems. The one I'm currently working on, however, had an unlevel, and upon closer inspection, broken cast iron flange. One of the slots for the closet bolts was also broken. After looking through the many forums online, I fairly easily removed the old flange and now have my 4" cast iron pipe. I looked in HD and found a replacement flange that fits over the pipe and clamps down on it. My main problem is that I won't be able to bolt the flange down to the slab, as there is about an inch gap all around the pipe. The old flange wasn't bolted to the slab, but it was also leaded in. Do I need to bolt the new flange down to the slab or will the clamping pressure around the pipe be enough. I'm concerned that, even though you don't have to tighten the closet bolts too much, the force being pulled against the new flange would cause it to eventually start loosening or sliding up off the pipe.

Any and all help is greatly appreciated!!