Column Selection and Installation Guide

The first decision comes before the product: will the column clad an existing pier, stand free, or carry a load? Each scenario needs a different product and a different fixing. The second decision is the diameter: when cladding, the inner diameter must exceed the widest point of the pier, otherwise the two half shells will not close. This guide covers seven steps from scenario to topcoat.

• Fine-tooth hand saw or mitre saw • PU-based mounting adhesive (NOT silicone) • Cordless driver and screws of suitable length • Plumb line or laser • Elastic mastic (expansion joints) • Acrylic filler • 180-220 grit abrasive • System primer and topcoat • Damp cloth

1) Define the scenario Three options: cladding an existing pier (half column), a free-standing decorative column (full round), or a column under load. Where a load exists it is carried by an internal steel frame, not by the column, and no concrete is poured inside. 2) Choose diameter and length For cladding, measure the widest point of the pier and choose a larger inner diameter. For free-standing columns the diameter follows the visual weight and the scale of the space (Ø10-Ø38 cm). The standard shaft is 240 cm, 260 cm in the twisted range; taller rooms need a joint. 3) Mark the base and axis Mark the base position on the floor and the column axis with a plumb line or laser. In a row of columns, distribute the spacing evenly and keep base levels aligned. 4) Place and fix the shaft When cladding, the two half shells wrap the pier; a PU-based mounting adhesive is applied in an uninterrupted bead to the mating faces and the pieces are CROSS-screwed at top, middle and bottom with heads sunk into the material. Silicone-based adhesive is not used; curing takes about one hour in normal conditions. 5) Fit capital and base The capital seats on top of the shaft and the base below; both are bonded and secured with two screws on each side. The order (Doric, Ionic, Corinthian) sets the style, and the base closes the shaft-to-floor junction. 6) Close joints and movement gaps Shaft joints and vertical connections are filled flush with acrylic filler and sanded at 180-220 grit. In steel construction, thermal expansion joints are sealed with ELASTIC MASTIC rather than rigid filler, so metal movement is not transferred as cracks. 7) Prime and topcoat Mat and clean the whole surface at 180-220 grit, apply the system primer homogeneously and then the topcoat. The primer must be the system primer of the topcoat brand. Outdoors an elastic, UV-resistant facade paint is used.

The table summarises six common situations, the product choice and the critical point of each. Choosing the wrong scenario is the most common error: loading a decorative column.

One shaft, one capital and one base per visible column. In cladding, the shaft consists of two half shells counted as one item. Above 240 cm a second shaft is added and the joint is concealed with a base, collar or band. About 10% cutting allowance is enough — waste is lower than with cornices or panels because pieces arrive at fixed lengths.

First, loading a decorative column: the shaft is not structural and a load needs a steel frame. Second, pouring concrete inside: the fill expands with heat and moisture and stresses the shaft. Third, choosing too small a diameter for cladding, so the shells do not close. Fourth, sealing an expansion joint with rigid filler in a steel structure; elastic mastic is required. Fifth, relying on adhesive alone instead of cross-screwing the joints.

Measure the widest point of the pier and choose an inner diameter larger than that, otherwise the two half shells will not close at the vertical joints.

Three: shaft, capital and base. In cladding applications the shaft consists of two half shells.

The standard shaft is 240 cm (260 cm twisted). In taller rooms a second shaft is added, cross-screwed at the joint and concealed with a base, collar or band.

A PU-based mounting adhesive; silicone-based adhesive is not suitable. The shaft is cross-screwed at top, middle and bottom, and capital and base take two screws on each side.

Thermal expansion joints are sealed with elastic mastic rather than rigid filler, so vertical and horizontal metal movement does not appear as hairline cracks.