Does the tip-over warning apply only to certain wall types?
The tip-over warning applies universally regardless of wall type, and the bookcase must always be secured to the wall. However, the type of screws and plugs you use will vary depending on your specific wall material. If you are unsure about your wall type, the manual advises seeking professional guidance. (Page 2)
From the official Ikea Billy Bookcase manual, page 2
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