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New Columns

Launch Slideshow

Replacing Giant Columns

Fitting things together

Replacing Giant Columns

Fitting things together

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    The most obvious degradation was seen at the base of the columns--thought to have been caused by contact between the wood and the damp plinths that they rested on.

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    To prevent moisture from ruining the columns again, the author installed polycarbonate spacers at the bottoms of the new columns to isolate the wood from the damp stone plinths.

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    Two-piece fiberglass bases replaced the old wooden ones; vent holes drilled in the bases were covered with screen to keep bugs out.

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    The fiberglass capitals on the existing columns were salvaged and reused.

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    Replacing the columns at each end of the porch was complicated by scribed trim and abutting rooflines.

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    One of these columns also concealed a Parallam post that supported the end of a load-bearing beam.

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    At the end of the colonnade, the carpenters used one of the old columns to practice scribing to the adjoining porch roofline.

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    A plywood template helped in orienting the flutes to the existing trim.

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    Where the support beam of the adjacent deck dies into the column, a recip saw was used to create the beam pocket.

A decision was reached to go with matching columns, and an order was placed with Somerset Door and Column, a company outside of Pittsburgh. It was late January 2010 when the new columns arrived. They are made from 10/4 Spanish cedar, with two coats of oil primer on the outside and asphalt tar on the inside.

The new columns weighed over 1,200 pounds apiece. In order to move them, we brought in an extended-reach forklift. To protect the lawn from the machine, we laid out 40 sheets of 3/4-inch plywood (see slideshow), creating a path between the drive and the front of the house. This turned out to be a good idea, as there was lots of precipitation during the course of the job; twice, the site received more than 18 inches of snow. 

We moved the columns from the staging area using a pair of straps. Once the column was in front of its final location, the lift operator used a single strap attached near its top to swing it into a vertical position and set it on a temporary platform in front of the porch, where we secured it to the scaffolding for stability. Because there was so little clearance for the new columns between the bottom of the architrave and the top of the limestone plinth — only about 3/4 inch — there was no way to move the column into place with the strap attached. So we fashioned a cradle for the lift that allowed the operator to pick up the column by the shaft. Working from the scaffolding, we attached the columns to the cradle with three ratchet straps, then the lift operator — with a very steady hand — inched them into place. We also used the cradle for removing the original columns.

Installation Details

To prevent moisture from wicking up into the new columns, we screwed 1-inch-thick polycarbonate spacer rings, supplied by the manufacturer, to their bottoms before we installed them. In addition, we drilled a series of 1-inch holes around the bottom of the columns to provide ventilation. These holes were covered by new two-piece fiberglass base assemblies, in which we also drilled vent holes, on the bottom of one of the radius moldings where they couldn’t be seen. On the inside we glued insect screens over the holes to keep bugs out.   

We also drilled vent holes in the tops of the columns. These holes were covered by the hollow two-piece fiberglass capitals that we salvaged and reinstalled. To complete the ventilation path, we installed two 2-inch-diameter louvers in the back of each capital where they wouldn’t be obvious. We also added several 1-inch louvers in areas of the capitals that couldn’t be seen from below.

Securing the columns. Following the engineer’s specs, we attached four Simpson A-24 L-brackets to each column with 1/2-inch-diameter Spax lag screws, then secured the brackets to the plinths with stainless-steel wedge anchors. The upper connections were similar — four brackets per column attached with Spax lags, with the brackets anchored to the roof framing with 5-inch LedgerLok screws. All the A-24 brackets were primed and top-coated twice before installation.