Porch Column Replacement

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MCReaper

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Hello all,

If this isn’t the right place to post this I apologize, I wasn’t sure where this question would fall.

I have a custom colonial house with about a 3’ roof overhang between the 2 stories. The 4 columns that connect to that overhang roof and concrete are rotted and need to be replaced. The columns are hollow wood with metal anchors into the concrete. The anchors are rusted completely and disintegrating. I want to replace the posts and use aluminum plinth bocks underneath but do the plinth blocks need to be anchored to the concrete?
 
Welcome to the forum. If you can post a photo both close up of the base and also a wide shot showing the whole picture it would help. Also maybe the age of the house/column.



Most of the wood ones I have run across are only bad at the bottom and most of the damage was in the base block. I have had some luck with just adding a new base and maybe trimming the column a little.



Maybe provide a link to the aluminum ones you are looking at.

Welcome to the forum.
 
Hello all,

If this isn’t the right place to post this I apologize, I wasn’t sure where this question would fall.

I have a custom colonial house with about a 3’ roof overhang between the 2 stories. The 4 columns that connect to that overhang roof and concrete are rotted and need to be replaced. The columns are hollow wood with metal anchors into the concrete. The anchors are rusted completely and disintegrating. I want to replace the posts and use aluminum plinth bocks underneath but do the plinth blocks need to be anchored to the concrete?
no the blocks would attach to the column which is attached to the concrete.
 
Something similar to what they do here would work. You'll just need to use something like tap-cons or another concrete anchor instead of wood screws to fasten the base to the concrete.

If you're going to replace with an aluminum plinth the same principal applies, it will still need anchored to the concrete in some way. The anchors don't need to support a constant load in any way but they're there to make sure the base of the column never moves. As soon as the column is no longer vertical, the loading forces on it will continue to move it out farther and farther out of vertical over time and it will also no longer support the load it was rated for.

There are some instructions here for installing an aluminum plinth and how to anchor it. They recommend dowels into the concrete at the corners under the plinth.
 
Thank you all for the replies. Here are some images as requested. There are 2 images showing the base of the posts (1 with the aluminum flashing removed), the top, and the front porch area.
Plan is to:
Use a bottle jack/support so jack up near the post and replace them using solid or someone at minimum equivalent to what is there except with aluminum plinth blocks. Lower it and repeat for the corner.
A lot of what I’ve seen, they don’t anchor the block to the concrete, gravity and the weight of the roof does that. I understand longitudinal load and why you would add anchors.
 

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Thanks for the photos. My guess is there is a 4x4 inside there and the boards you see rotted out may just be a covering. The 4x4 could have been a PT lumber and may well still be good and in that case I would just replace the full outer covering boards.

I could be wrong but I would start by removing some of the bad wood and take a look inside.
 
In that case I would think the roof truss system is designed to allow that amount of overhang cantilevered out and likely the columns are just cosmetic and not required to carry load.

If it were mine I would remove them one at a time and maybe build new ones with a 4x4 center and trimmed out. You could do the whole thing with PT and then skin it with aluminum or use PVC lumber and have no upkeep.
 
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