Wall Anchors by Hole

Wall plugs for brick and masonry

A plastic wall plug (the Brazilian bucha, made famous by the German brand Fischer and its S series) holds by friction. You drive a screw into it, the plug swells inside the hole, and that pressure against the wall is what keeps everything in place. As a working rule, hole ∅ = plug ∅ + 0.5 mm, so a 10 mm plug calls for a 10.5 mm bit. You'll see ∅ 6, 8 and 10 mm most often, and each one has a screw size that goes with it.

Which bit you reach for depends on what you're drilling into. Concrete and stone want a masonry bit with hammer mode; for hollow ceramic brick, switch to a masonry bit with rotation only and turn the hammer off, or the brick's inner walls crumble and the plug just spins. Holding power swings a lot too. That same 10 mm plug holds around 50 kg in solid concrete but only about 25 kg in hollow ceramic brick. When the fixing really matters, check ABNT NBR 9442 and the manufacturer’s pull-out test data before you trust it.

Applications

Shelves, TV brackets, mirrors, kitchen cabinets, towel rails, curtain rods, the support for an AC condenser, clamps for electrical conduit. Size the plug for the load and for what's behind the wall, both. The number one reason a fixing pulls out is a hole drilled too wide in hollow brick.

FAQ

Which screw goes with each plug? Roughly: 4 mm screw in a 6 mm plug, 5 mm screw in an 8 mm plug, 6 mm screw in a 10 mm plug. The manufacturer’s chart is the real authority, so confirm there.

The plug spins inside the hole, what now? Either you drilled too big or the brick is hollow. Move up to a metal toggle (parabolt), a chemical anchor, or one of the longer nylon plugs built for hollow walls.

Can I reuse a plug? No. The plastic has already expanded once and won't grip the same way again. Put in a fresh plug even when the screw still looks fine.