Lag bolts, toggles and anchors for TV mounts

A TV mount usually ships with one bag of hardware and instructions that assume wood studs. Half the walls we see need something else. Here's what each fastener is for.

Lag bolts (lag screws) — wood studs

The standard. A thick, coarse-threaded screw with a hex head, typically ¼″ or 5/16″ diameter and 2.5 to 3 inches long.

• Pilot hole: always. About 60–70% of the bolt's diameter (3/16″ for a 5/16″ lag). Too small and the stud can split or the bolt can snap; too large and it won't grip.
• Depth: at least 1.5 to 2 inches of thread in the stud itself, after passing through the drywall.
• Position: the centre of the stud.
• Tightening: snug with a socket, then stop. An impact driver can strip the hole in a second.

Structural wood screws

Modern self-drilling structural screws do the same job as lags with less splitting. Fine if they're rated for the load.

Toggle bolts for metal studs

Steel studs are thin sheet metal; a lag bolt has almost nothing to bite. Heavy-duty strap or snap toggles pass through a hole in the stud and brace a metal bar across the inside. Used through the stud's face, they're the accepted method. Details in mounting on metal studs.

Toggle bolts in bare drywall

The same toggles hold well in drywall for static loads, but drywall crumbles under leverage and movement. For small TVs on fixed brackets only; see can drywall anchors hold a TV.

Sleeve anchors and wedge anchors — brick and concrete

• Sleeve anchors: a bolt inside an expanding metal sleeve. Good in brick, block and concrete; forgiving of slightly imperfect holes.
• Wedge anchors: strongest in solid poured concrete. Not for hollow block or soft brick.
• Concrete screws: thread directly into a precisely sized hole. Quick, removable, fine for moderate loads in sound masonry.

All need a hammer drill, the exact bit size and a clean hole.

Plastic wall plugs

Supplied with many mounts "for concrete". They're adequate for a small TV on a fixed bracket in solid concrete and not something we rely on for anything heavy or articulated.

Machine screws — TV side

The bolts that go into the back of the TV are metric machine screws: M4, M6 or M8 depending on the set. Use the size that threads in easily by hand, with spacers if the back is curved or recessed. Too long a screw can bottom out and damage the TV; too short and only a couple of threads hold.

Washers

Use them under lag-bolt heads so the head bears on the bracket evenly and doesn't dig into a slot.

Quick reference

Wall	Fastener
Wood stud	5/16″ lag bolt or structural screw
Metal stud	Heavy-duty strap toggle through the stud
Brick / poured concrete	Sleeve or wedge anchor
Hollow block	Sleeve anchor or masonry toggle
Drywall only	Not for most TVs

We bring all of these to every job, so the right fastener doesn't depend on what came in the box. Labor from $94.