Bottom fastening

The Strofix bottom fastening is an AISI 304 stainless-steel base plate for the Ø42.4 mm railing post tube, available in three configurations with different plate diameters, finishes, and bolt hole sizes. All variants have three bolt holes and are attached by welding (elements for welding included).

The Ø100 mm satin variant has a 6 mm plate thickness and three Ø11 mm bolt holes (for M10 bolts). The Ø90 mm raw surface variant has a 4 mm plate thickness and three Ø9 mm bolt holes (for M8 bolts). The Ø85 mm satin variant has a 6 mm plate thickness and three Ø8.5 mm bolt holes (for M8 bolts). The satin-finished variants (Ø100 and Ø85) are designed for visible installations where the base plate is not concealed by a decorative cover — the polished surface provides a finished appearance. The raw-surface variant (Ø90) is intended for installations where the base plate is hidden under a cover.

Select the plate diameter and surface finish in the dropdowns at order time.

Use cases:

• Visible base plate installations where satin finish is required (Ø100 or Ø85 mm)
• Exposed post bases on railings, balustrades, or staircases where no cover is used
• Concealed installations using the Ø90 mm raw-surface variant under a decorative cover
• Three-bolt M10 anchor pattern with satin finish (Ø100 mm variant)
• Compact three-bolt M8 anchor pattern with satin finish (Ø85 mm variant)

FAQ:

What configurations are available?

Three configurations, each with different plate diameter, thickness, bolt holes, and finish:

Ø100 mm, satin: h = 6 mm, 3 × Ø11 mm (M10). Ø90 mm, raw surface: h = 4 mm, 3 × Ø9 mm (M8). Ø85 mm, satin: h = 6 mm, 3 × Ø8.5 mm (M8).

Why do some variants have satin finish?

The satin-finished variants (Ø100 and Ø85) are designed for installations where the base plate remains visible — no decorative cover is placed over the base. The satin finish matches other Strofix satin-finished railing components. The raw-surface variant (Ø90) is intended for concealed installations under a cover.

What bolt sizes do the holes accept?

The Ø100 mm satin variant has Ø11 mm holes for M10 bolts. The Ø90 mm raw and Ø85 mm satin variants have Ø9 or Ø8.5 mm holes for M8 bolts.

How do the satin variants compare to the raw-surface base plates?

The previously documented raw-surface base plates (D80 and D100) have a 4 mm plate thickness and are designed to be concealed under covers. The satin variants on this product have a 6 mm plate thickness and a polished surface for visible installation. The thicker plate on the satin variants also provides greater rigidity.

How is the post tube attached?

The post tube is welded to the base plate using TIG or MIG welding.

What post tube does this fit?

All variants fit the Ø42.4 mm round post tube.

About Base & Clamp Fastenings

A base or clamp fastening is a stainless-steel plate or bracket that anchors a railing post to the building structure, forming the structural foundation of the balustrade. Bottom fastenings bolt to the top of a floor slab, deck or beam, while side fastenings bolt to the vertical face of a fascia, edge beam or wall. Assembly clamps grip an existing tube or post without welding, and assembly plates provide a flat mounting surface for auxiliary connections.

Strofix supplies 18 base and clamp products for Ø42.4 mm round pipe and 40×40 mm flat-sided square posts, with plate diameters from Ø80 to Ø100 mm (round) and plate dimensions from 80×80 to 135×56 mm (rectangular/square), in satin or raw-surface stainless steel with AISI 304 and AISI 316 options.

Screw-hole configurations include 2, 3 and 4-hole variants. The correct fastening depends on mounting orientation, post profile, plate size, number of screw holes and the required surface finish.