This is a bit subject to the size and holding power of the
fasteners, "the bite" of the fastener, the weight of the door,
etc. Someone (think angry wife) slamming a solid core door will
certainly jar a door casing and wall much more than a hollow core.
You can tell if the anchor got a good bite. I prefer Powers
NailIn anchors. when setting steel door jambs, two on each side.
Your issues are different, one good anchor will suffice if you
feel it grab well. Tapcons are great, but there are certainly
other commercial anchors. I prefer drilling a hole through base
plate and concrete with a masonry bit, inserting one or several
pieces of electrician's wire or tie wire and driving a nail in the
hole. You'll need a 4' crowbar to pull them out.
Keep the whole world singing . . . .
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