Base for welding 40x40mm, Raw

The Strofix bottom fastening for welding is an AISI 304 stainless-steel cast base plate for the 40 × 40 mm square railing post tube. The plate measures 100 × 100 mm with an open square aperture at the centre, reinforced by cast ribs running to each corner. Supplied with a raw (unfinished) surface.

The post tube passes through the central aperture and is welded to the plate, giving a fully rigid post-to-base connection. The plate is then bolted to the floor, slab or substrate through the clearance holes in the flange. The cast ribs stiffen the plate against bending under post loads.

The raw surface finish is standard for welded base plates, which are typically concealed by a decorative cover after installation. AISI 304 stainless steel is suitable for standard interior and exterior installations.

Use cases:

• Welded floor mounting of 40 × 40 mm square railing post tubes to concrete slabs
• Structural post foundation for balcony and terrace railings
• Square post base for staircase railing installations
• Workshop prefabrication — weld post tubes to base plates before site installation
• Concealed base fixing under a decorative cover plate

FAQ:

What post tube does this base fit?

The central aperture takes the 40 × 40 mm square post tube. The tube passes through the plate and is welded to it.

What are the plate dimensions?

The plate is 100 × 100 mm, with cast reinforcing ribs running to each corner.

How is the post tube attached to the plate?

The post tube is welded to the base plate. TIG or MIG welding is required. This is a professional installation step, typically carried out in a workshop before site delivery.

Why is the surface finish raw?

Welded base plates have a raw (mill finish) surface because the weld itself is ground and finished on site, and because the plate is normally concealed by a decorative cover afterwards. The Strofix Covers category includes cover plates for both square and round post bases.

Is there a version that does not need welding?

Yes. The hammered base for the same 40 × 40 mm post tube has a socket formed from the plate and is supplied with a satin finish, so it can be left exposed.

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.