Apparatus includes body assembly configured for installation to wall assembly and baseboard. Visual-reveal feature is formed between body assembly and baseboard once body assembly and baseboard are positioned, body assembly is installed to wall-support structure that abuts against and supports weight of wall assembly, and baseboard is installed to body assembly. Body assembly includes wall-support contact portion configured for positioning adjacent to wall-support structure. First engagement assembly extends from wall-support contact portion. Second engagement assembly is configured to attach to baseboard. Second engagement assembly and first engagement assembly are configured to engage with each other. Body assembly also includes wall-contact portion configured to contact outer wall surface of wall assembly. Finished-edge portion extends from wall-contact portion. Finished-edge portion is configured for positioning proximate to wall edge of wall assembly. Visual-reveal feature is positioned between baseboard edge of baseboard and wall edge of wall assembly. Visual-reveal feature includes channel having vertical height and horizontal depth.