New Columns for an Old Porch

A composite column being installed. Note the 1 1/2-inch PVC extension at the top of the column, which lowers the position of the decorative trim rim around the column. The extension will be covered by the capital once it is lifted in position.

The original beams—which were actually framed like short knee walls and clad with board sheathing—had water damage, so the author reframed them with PT lumber and clad them with PVC trim. Then he prefabricated U-shaped PVC soffit/fascia assemblies and slipped them into place.

To lower the height of the column's decorative trim rings, the author screwed plugs made from a double layer of 3/4-inch-thick PVC into the the tops of the columns.

The actual column extensions are another pair of slightly larger PVC plugs sized to match the outside diameter of the columns. The author routed a channel and center hole to match the flashing cap profile, then screwed the extensions to the plugs in the columns with stainless steel screws.

The author cuts the composite columns with a 4 1/2-inch angle grinder equipped with a diamond masonry blade. The angle grinder provides a smoother cut than a carbide blade in a circular saw, and running a shop vac while making the cut captures most of the fiberglass dust.

Instead of using the supplied screws to fasten the metal installation clips to the base of the column, the author used stainless steel bolts and nuts instead.

The tops of the columns fit into flashing caps screwed to the underside of the beams.

The bases of the columns are secured to the brick porch with 5/16-inch-diameter by 2 3/8-inch-long Tapcon masonry screws driven through the installation clips.

After gluing the capitals to the flashing caps with OSI Quad Max sealant, the author used masking tape to hold the capitals in place until the sealant cured.

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