1. Four main types
Wedge — expansion-based, for heavy loads in dense concrete (no lower than B20). Drop-in (with internal thread) — for suspended structures under the ceiling, fitted with an anchor bolt. Chemical — a two-component compound that works where expansion is impossible (thin walls, hollow blocks). Frame — a long anchor with a hex head, for fixing window and door frames through the casing.
2. Relation to the concrete grade
The allowable load in the data sheet is given for B25 concrete at the standard embedment depth. For B15, reduce it by 30–40%. In hollow foam blocks a wedge anchor does not work: only a chemical anchor with a mesh sleeve.
3. Minimum distances
From the edge of the concrete — no closer than 6 hole diameters. Between two anchors — no closer than 10 diameters. Violating these rules is the main reason for the concrete edge spalling during tightening.
4. Hole preparation
Drill bit diameter — strictly per the anchor data sheet. Depth — 5–10 mm deeper than the anchor length, to leave room for dust. After drilling, blow out the hole with a blower bulb or compressed air twice. Without blowing out, a chemical anchor loses up to 50% of its adhesion.
5. What most often goes wrong
Tightening with a torque wrench exceeds the rated torque → the anchor strips out. Drilling with a rotary hammer without the “no-hammer” mode in tile → a crack in the tile. Installing a wedge anchor in fresh concrete less than 28 days old is prohibited.
A demanding project? Send us the connection detail with the load and concrete grade — a manager will select an anchor with a safety margin and a batch certificate.