How necessary is anchoring a bookshelf to drywall?

With full acknowledgement this may be a stupid question, I’ll ask it anyway:

I’ve built an Ikea-like bookshelf unit from a kit. It comes with a screw and plastic drywall anchor. The shelves are 6 feet tall and free standing (i.e. not supported by the wall in any way).

How necessary would you consider attaching the drywall anchor? Does it really help the case’s stability that much, or is it more likely to do more damage to the wall than it’s worth?

Do you ever have little kids in the house? If so, use the anchor.
If not, and you don’t live in an earthquake-prone area, it’s probably not very necessary.

No kids, but a small dog. Though he’s not bad about bothering bookshelves.

You don’t typically want to anchor bookcases etc. to drywall; it’s a very poor third or fourth choice.

Anchoring them via a short strap or chain to a stud within the wall is a good idea.

I prefer to use angle brackets, reversed behind the rear of the bookcase, screwed into studs and then screwed into the top of the bookcase. It’s a very suspenders-and-belt kind of thing but it can prevent all kinds of injuries, damage to artworks, etc.

If you live in California, or anywhere else that gets earthquakes, or if you have small children, I’d say to install the detail mounts. If not, I wouldn’t bother.

Kids and dogs getting squashed are the biggest concern.

I’ve never seen a bookcase attached to the wall. That seems to be a new thing because of liability concerns. My parents had an encyclopedia set in a bookcase and it never squashed me. I don’t think it ever wobbled in the thirty years it sat against the wall.

The hole is small and easily patched whenever the bookcase is taken away. It’s a super-cheap insurance policy against a somewhat unlikely but potentially disastrous mishap (definitely bad for your books, conceivably bad for a person under them).

To reduce the risk of damage to the fragile dry wall, find the solid stud inside the wall and install the strap there. It doesn’t have to be central to the bookshelf.
The reason that the seemingly “too thin, too small” strap can hold the bookshelf upright is due to its mechanical advantage… and the way the book shelf that is only leaning a little only has part of its weight unbalanced.
Torque is force times minimum/perpendicular distance from point of rotation.

So the leaning bookshelf has only a little net torque. The strap can easily produce that torque because it operating in (approximately) the horizontal plane …which means its perpendicular distance from the point of rotation is far larger… When the strap comes tight its mechanical advantage could be 500 !

find a stud behind the shelf area. put a small metal right angle(s) on a shelf(s) into that stud.

a hold into the stud will patch well and cause no damage.

I have lots of bookshelves and they’re all free-standing. I’ve never had one fall over.

If the book case doesn’t have a back on it they may want the straps installed to keep it from working side to side and eventually failing.

Many people like to face their books so the spines are lined at the front of the shelves. This could cause an Ikea bookcase to become unstable. That being said, I’ve never had a book case fall over, and I have cats.

If you want your dry wall to fall on you simultaneously with the bookcase, then, it’s very important to anchor the case to the wall.

All my bookcases are anchored to the wall. But then, I live in California and have seen first-hand what earthquakes can do. The 1994 Northridge quake threw bookcases in my parents’ house across the room.

That’s a good point. I was assuming you’d have the books pushed in to the back of the shelf. This means the center of gravity has the shelf leaning in to the wall. If you have the books at the front of each shelf, the center of gravity will also move forward and make the shelf less stable.

My Ikea bookcases go round the corner of two walls with the corner unit in the middle. I’ve connected them together along the top with mending plates.

on my only freestanding bookcase I have an L bracket screwed directly into a stud. Drywall anchors are only good for making big holes in walls.

A good alternative to anchoring is to install a small wedge (or wood shim) under the front of the bookcase. Bookshelves are usually an inch away from the wall due to the molding and installing a wedge will make them lean slightly towards the wall. However, where small kids or earthquakes are involved, all bets are off.

I live near there and yes, living in an earthquake area presents all sorts of opportunities for safety. Do you have anything hanging on the wall above your bed? How about tall dressers in the room that could fall on the bed? Anything stored on top of tall shelves or cabinets? etc. etc. etc.

I have a relative-by-marriage who has a relative-by-marriage who had a five year old boy pull a TV stand over onto himself, crushing his head and killing him. All of our furniture has been anchored since then.

I’ve had such shelves for 20+ years, in a non-earthquake area, and the never fall over.

But what has happened to me is that over a long period of time, they may start to shift slightly to the right or left. This gets progressively worse if you don’t catch it in the beginning. Combined with gradual sagging of the individual shelves, in some cases the shelves have fallen.

I do believe that anchoring the bookshelf to the wall will prevent the left/right collapse, but a much easier way would be to add one or two diagonals to the back of the unit. A thin 1- or 2-inch wide strip of wood is quite adequate, the longer the better. Nail it in at one corner, and the other end at the corner which is diagonally opposite. Putting in two in an X shape is even better. Use a ruler, and you can guarantee that the shelves are in at perfect 90-degree angles to begin with. The extra bonus of not anchoring to the wall is that the shelves can still be moved when necessary.

(If you do what I have described, you might notice that these strips are quite long and flexible, and can be easily moved to and fro (i.e., perpendicular to the back panel). That’s okay. The goal is to prevent this perfect rectangle from turning into a parallelogram, and to do that, you only need to prevent each corner from moving further from its opposite corner.)