While standard Sempervivum (Hens &Chicks) are known for sending out young plant offsets on stolons from a central mother rosette, new growth in S. heuffelii arises through crown division. S. heuffelii varieties develop offsets right in the middle of an older rosette. As leaves emerge and enlarge, the clump expands to make room for the new, individual rosettes.
Propagating By Hand
Without any effort on your part, S. heuffelii will propagate and expand on their own to form a neat colony. You can, however, take a hands-on approach and manually divide the crowns with a sharp, clean knife. This gives you more control over the size and location of your colonies. When you cut a rosette into pieces, be sure that each portion has a bit of root tissue attached. Re-plant the sections in well-draining soil and water normally as they regenerate roots and full rosettes.
For more information, check out the full post on Propagating Sempervivum heuffelii.