Molly Bolt - Hollow-Wall Anchor for Drywall Repair

A molly bolt is a hollow-wall anchor that expands behind drywall or plaster so a screw can hold light to medium loads securely.

What It Is

A molly bolt is a metal anchor designed for walls where there is no stud directly behind the surface. When the screw is tightened, the sleeve expands and grips the back side of the drywall or plaster, creating a stronger hold than an ordinary screw driven into gypsum alone.

Homeowners use molly bolts for mirrors, shelves, curtain hardware, and other fixtures that need more support than a plastic anchor can provide. They are reliable when matched to the wall thickness and load, but they are still limited by the strength of the wall surface itself.

Types

Standard molly bolts are sized by screw diameter and wall thickness range. Some are pointed for easier starting in drywall, while others require a predrilled hole and are better for harder plaster surfaces. Short versions fit thin wallboard, and longer sleeves are made for thicker plaster or double-layer drywall.

Where It Is Used

Molly bolts are used on interior drywall and plaster walls where a fastener must hold without direct framing behind it. They are common for towel bars, small shelving brackets, decorative items, and utility accessories in finished rooms.

How to Identify One

A molly bolt has a machine screw threaded into a metal sleeve with a flanged head. Once installed, the visible part usually looks like a screw going into a small metal collar at the wall surface. If removed, the back side of the sleeve will appear spread open like legs or petals.

Replacement

A molly bolt should be replaced when it spins in the wall, loosens under load, or tears the drywall around the anchor. The usual repair is to remove the failed anchor, patch the damaged hole if needed, and install a new anchor sized for the wall and weight. If the item is heavy or frequently pulled on, fastening into a stud or backing is a better long-term solution.