Rebar Hanger Placement and Final Foam Application Top center hanger with wire/string attached is used as a guide to mark for rebar hangers over the entire interior surface. Rebar hangers are often placed in rows about 10-inches apart (sometimes 14-inches – depending on engineering). Be certain before placing hangers to check specified engineering. Layout pattern of rebar hangers. Rebar hangers set in place on the marked lines.