The author's firm had been hired to replace the bases of six 100 -year-old wood columns; engineer's inspections had indicated that the upper portions of the columns were sound, and there were other good reasons not to disconnect them from the roof structure entirely. As it turned out, much more was needed.
To temporarily support the porch roof while the columns were replaced, the carpenters built posts from 10-foot-long 2x4s and 2x6s.
To start, the assemblies were sheathed with 1/2-inch plywood. Full-length 2x4 strongbacks were added to the outside for rigidity.
Double-post assemblies were joined by top and bottom plates stacked two high in order to support the roof while work was being performed on the columns.
The original plan was to replace only the column bases. Accordingly, the crew installed structural steel clamp rings around the shafts and shifted the weight from the pedestals to the concrete porch using 20-ton hydraulic jacks.
Rings of bending plywood served to guide the cutting of the wood columns, which was done with reciprocating saws and circular saws.
When the bases were removed, it was discovered that the interiors were delaminating and that the columns would have to be replaced in their entirety.
After cutting away the bases, the crew placed cribbing under the shafts while awaiting the delivery of new columns.
Sheets of 3/4-inch plywood protected the lawn from the lift that was used to transport and place the new columns..