Question 1

What material should the posts be?

Accepted Answer

A profile tube of 60 × 60 × 2 mm or 80 × 80 × 2 mm suits fences up to 2 m. A round Ø76 mm post is common for gates and wickets. Cap the top of the tube — water inside freezes and bursts the metal.

Question 2

How deep should I concrete them?

Accepted Answer

Below the frost line plus 20 cm. In a temperate region that's 1.0–1.2 m; in colder regions, 1.5–1.8 m. On heaving soils (clay, loam), go deeper or use screw piles.

Question 3

Should I add crushed stone under the post?

Accepted Answer

Yes — 10–15 cm of 20–40 mm crushed stone at the bottom of the hole. It drains water away from the post base. Without drainage, water stagnates, freezes and pushes the post up in spring.

Question 4

What grade of concrete do I need?

Accepted Answer

M200 (C12/15) is enough for most fences. A typical mix is M400 cement : sand : crushed stone at 1 : 3 : 5. Per 0.1 m³ of concrete, that's roughly 25 kg cement, 75 kg sand and 125 kg crushed stone.

Question 5

When can I hang the panels after concreting?

Accepted Answer

No sooner than 7–10 days (about 50% strength at +15 °C). Full strength comes at 28 days. Below +10 °C, the strength-gain time roughly doubles.

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