Anchor selection: cracked concrete is the default

Reinforced concrete is expected to crack in tension — the steel is there precisely to carry that load. So specifying an anchor for uncracked concrete is a bet on where the crack will not go.

Reading the approval

• Option 1. Cracked and uncracked concrete, all load directions. The safe default.
• Option 7. Uncracked concrete only. Fine for a non-structural fixing in a slab you can assess, wrong for anything in a tension zone.

The option number is on the ETA and usually on the box. If neither states it, treat the anchor as unapproved for structural work.

Embedment and edge distance

Two figures kill more fixings than product choice: effective embedment and edge distance. Drilling shallow to avoid rebar, or fixing too close to a slab edge, reduces capacity far more sharply than most people expect — and neither shows up on a pull test done in the middle of a bay.

Blow the hole out. An uncleaned hole can lose a large share of its rated load, and it is the most common reason a correctly specified anchor fails.

Written for Forgeline Tool Supply — a demonstration store. See the AgenticEcom Suite.