IMPORTANT: Spray adhesive is ineffective at bonding foam to painted or bare concrete or cinderblock walls. For permanently adhering foam directly to these surfaces, heavy-duty construction adhesive is suggested. Note that this will damage the foam and leave residue on the wall if removed. For non-permanent installation, we suggest mounting the foam to a substrate, such as plywood or sturdy cardboard, and hanging the mounted tile(s). Our spray adhesives may be used to form the foam-to-substrate bond.