Pfostenanker

Pfostenanker (German for "post anchor") are metal fittings used to secure vertical posts to foundations or the ground. They are common in timber construction for fences, railings, pergolas, decks, signposts and small load-bearing structures. By lifting the timber off the substrate or anchoring it directly, Pfostenanker reduce moisture contact and biological decay while providing a defined connection for vertical, lateral and uplift loads.

Several types exist: spike or driven anchors for soft ground, base-plate anchors bolted to concrete, U-shaped or saddle anchors that cradle a post, adjustable-height anchors, and cast-in or chemical anchors embedded in fresh concrete. Materials and finishes typically include galvanized or stainless steel to resist corrosion; heavy-duty anchors may be hot-dip galvanized or powder-coated for additional protection.

Selection and installation depend on post size, load requirements, ground conditions and exposure. Anchors are fixed with expansion bolts, through-bolts, screws or by casting into concrete; drainage, frost protection and separation between timber and wet concrete are important to prolong service life. Designers should follow manufacturers’ specifications and relevant building codes or standards (national regulations, Eurocodes or DIN standards) to ensure adequate capacity and corrosion resistance.

Advantages of Pfostenanker include easier installation and replacement of posts, improved durability of timber members and predictable structural behavior. Proper choice and maintenance are essential for long-term performance.