Maybe a bit out of the category here, but we need  help.

A friend, an excellent renovation and small house addition fellow, asks me to post a question for him.

He is working on a porch. The porch supports are of wood, in a long, tall  pyramid shape somewhat reminiscent

of the Arts and Crafts porch supports of some years ago.  

These supports have been replaced twice in ten years because they rot from the inside.  Outside, the paint

is great with no signs of cracks or leakage.  The supports are tightly sealed and held off the brick foundation

by another piece of wood such that the actual wood of the pyramid does not touch cement or bricks. 

  It is the bottom of the porch posts that are rotting from the inside.  There is no sign of leakage from above. 

So, we have a discussion on what to do.  One thought is to seal them yet better, inside and out so no moisture

gets in. Another thought is to put small vents in the top and bottom so air can circulate.  Ultimately, it

would be great to know what is causing this to happen.  

 

Of course,  the discussion also goes to what kind of wood to use.  I'm aware of the lists online of good outdoor wood.

Because this is to be painted and subject to this odd moisture issue, it seems worth asking that question in this

context.  

 

thanks

I’ll let the experts answer this but my novice suggestion would be to make the base from cypress.

Ron has a good idea. I am inclined to believe that the moisture is condensation inside the columns . If the base trim was made to allow air access from the bottom and drainage then I think that would solve the problem.

Just curious, do they hose the porch off frequently?

Might look at a metal cap for the top of the post...and slant it a bit, to get any water to run off...

IF I leave the tops of post out where rain can get to them, I bevel the top into a pyramid...they also make metal caps this shape...

( post is treat ground contact Pine) 

A picture would sure go a long way for us to fully understand the big picture - at least it would me.

They do sell post column base brackets to hold the post off the floor, I think that would be a lot better than a block of wood under the post.

Are the existing supports solid wood, or hollow?

 

I have to agree with Cal.  I don't have a good visual from the description and a picture would do wonders.  If the post is not cut to form the pyramid the water will run down the post and across the end grain and then sucked up into the post causing the rot.

 

 

 

Ah, now you are asking really good questions to which I have no answer.  

Back to my friend for clarification.

 

Thanks for these thoughts so far.  I gravitate toward condensation myself, though end grain on the bottom sucking up water make a whole lot of sense.

You know, the wisdom I get from this group is just fantastic.

Thanks,

9 hours ago, Bob Hodge said:

though end grain on the bottom sucking up water make a whole lot of sense.

In my deck rebuild I used clear caulk on every exposed end to try and keep the water from being sucked up inside.  Got this tip from a fence guys years ago.  Always seal the top of a fence post with clear caulk, and as @steven newman suggested a cap just for good measure.