I would not trust the good adhesion for heavy objects with a rough surface.
The FAQ at Command says so: Surfaces What surfaces do Command™ products adhere to? To painted, stained or varnished wood, glass, tile, painted concrete, plaster, metal and painted wallboard. Command™ products can also be used on smooth, sealed and finished surfaces, including plastic wall cladding and fencing, doors, windows, decking, guttering and cladding. The exterior product line is not recommended for rough surfaces, such as cement, brick or rough-sawn wood.
We had hung pictures for an exhibition with Command and it worked very well even on slightly rough surfaces. However, the pictures were not 7.5 kg and we applied a strip to all 4 corners. It also came off perfectly after about 5 months without leaving any residue.
