I need to repair some 100-year-old cylindrical porch columns. The columns are composed of roughly 3-inch-wide staves, shiplapped on the edges. Over the years the staves have shrunk at the bottom (their widest point), creating roughly 1/4-inch gaps between them at the column’s base. Previous owners have caulked the gaps, but eventually the caulk dries up and falls out.
My idea was to eliminate the gaps by gluing in roughly fitted wood strips with gap-filling epoxy for a more permanent fix. Question: will this potentially cause the wood to split someday because there is no allowance for additional shrinkage? Or is it reasonable to think that these old and relatively narrow staves have done most of the shrinking that they’re going to do?
Replies
Hi Tip,
I've done two similar jobs over the years. I think your wood is stable after 100 years but I would use a different product to fill in the gaps. I think the best thing to use would be "auto body putty" or Bondo. It can be difficult to control but leaves an easy to paint surface and it won't dry and fall out. Don't use to much hardner or leave too large a chunk to sand down. Being a woodworker, it is a rather gross product to deal with but it got the job done. Hope this helps.
Best Wishes, Dennis
I repaired some columns about 12-15 years ago by totally dismantling them and reassembling them with epoxy(West System) and they are still intact.One suggestion is to ensure top to bottom ventilation through the column.I use a small screened plug vent at the top and screened notches in the plinth.If possible try to paint the inside to balance the moisture absorbsion.
I will bet lunch that although it appears that the staves have 'shrunk' - the real culprit is compression set.
Compression set occurs when wood gets wet, wants to swell in dimension, but cannot due to constriction of some kind. Glued in door panels, glued breadboard ends, cross grain cabinet sides, etc, all exhibit compression set when they open up. The cells still swell, but their structure is compressed. Then when they dry out, cracks develop since the compressed wood will then 'shrink'. Fill these cracks with wood, Bondo, or anything else, and the wood will again compress (nowhere to go), and cracks develop, ad infinitum.
This means the real culprit is water wicking up into the ends of the staves, and perhaps some sort of solid fastening to the base. Any repair will start with removing what is under the staves, drying them out, applying a good grade of epoxy as a seal against further water penetration, then putting it all back together. Allow the column to expand/contract in diameter, or you will start the problem up all over again.
The comment about venting the column interior is valid. Let air in at the bottom and out at the top. Critical to the life of the column.
Dave S
http://www.acornwoodworks.com
These are porch columns. And even if they are protected from direct rain, they are still outside. This means that they are subject to the changes in humidity that "outside" gets.
That is true of the outside surface of the colums, and it is true of the inside surfaces of the hollow columns.
And wood -- even the hundred-year-old stuff -- changes dimension with changes in humidity. The dimensional changes will be more pornounced with wider boards -- hence the problem at the wider bottom of the columns.
In addition, the bottom of the columns have probably been subjected to some (small amounts) of condensation from the inside. As the warm, humid daytime air infiltrates the hollow, the humidity insidde the column increases. When the night gets cold, that humidity condenses and falls.
So, whatever you do, it needs to allow for (a little bit of) movement.
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