The main purpose of a grab bar is to support a person’s weight as they are standing still or moving vertically or laterally. Assuming that you are using an ADA compliant grab bar that will be located in the proper location for the specified user, your most important task is to ensure that the grab is installed securely.
According to the Fair Housing Act, "covered multifamily dwellings" must contain reinforcements in bathroom walls to allow later installation of grab bars around toilet, tub, shower stall and shower seat, where such facilities are provided. http://www.fairhousingfirst.org/fairhousing/coverage.html
The full text and drawings of Chapter 6 of the Fair Housing Design Act Manual “Reinforced Walls for Grab Bars” can be downloaded at https://www.huduser.gov/Publications/pdf/fairhousing/fairch6.pdf and is briefly reviewed in our blog called “Reinforcing Walls for Grab bars per the Fair Housing Act”
You can install grab bars to studs through tile, sheetrock or other wall material that is tight to the studs but you must hit the studs at each end of the grab bar with at least three screws at the depth recommended by the grab bar manufacturer. Always follow the installation instructions provided by the grab bar manufacturer. Although every room and its framing are different, most houses have wall studs that are 16 inches apart on center. Therefore, if installing grab bars into studs, you will need to use grab bars with incremental 16 inch lengths to anchor the ends into studs.
The remainder of this blog covers specific ways to add reinforcement to walls that are exposed - that is where the outer wall material has been removed and the wall studs are exposed.
Always make and keep a drawing of the location of the blocks for future reference.
Heavy plywood applied to the studs over a larger area can support grab bars and provide a base for the installation of finish materials such as ceramic tile or plastic wall panels. Plywood can be applied to the face of studs or “let in.” In either case the plywood must be of sufficient thickness and should be securely attached to withstand the forces specified in ANSI 4.24, or an equivalent or stricter standard (typically ¾” or thicker). Anchors for securing the grab bars to the reinforced walls should be through-the-wall type or another type capable of meeting the ANSI force requirements.
Since the space between the panels and the stud wall gets narrower as it approaches the top of the panels where they are fastened to the studs, this blocking must be cut to fit snugly in the space between the studs and the panel. The blocking must contact the plastic panel over the entire reinforced area.
NOTE: Some fiberglass and acrylic tubs, showers, and wall sections are now made with reinforcing already in the walls to stiffen the fixture. If the reinforced fiberglass or acrylic wall is not specifically labeled as built for grab bars and meeting the ANSI load requirements, then additional reinforcing may need to be installed.
To ensure that you are complying with all of Chapter 6 of the Fair Housing Design Act’s “Reinforced Walls for Grab Bars”, please download the chapter at https://www.huduser.gov/Publications/pdf/fairhousing/fairch6.pdf
You can find frequently asked questions about grab bar reinforcing at http://www.fairhousingfirst.org/faq/grabbars.html
See our blog called “Location Guidelines for Wall Reinforcing per the Fair Housing Act” for additional information about wall reinforcing.