Setting shed posts into concrete: should I treat seal the posts first?

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ilyaz

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I will be building a small lean-to shed and want to set the posts holding the roof into concrete. The standard procedure is to dig a hole, set the post, pour concrete to almost fill the hole then add dirt. Question: if I want my posts to last longer, should I seal the bottom part of my (pressure treated) post that comes in contact with conrete and dirt with anything? Either the end grain or the sides? I know that I should put gravel on the bottom of the hole under the post, but if I can add some extra protection by sealing it, I can do it. What sort of sealer would you recommend? TIZ!
 

ilyaz

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Ideally, but I am not going to pour a slab. I'll install the posts and the roof and maybe side walls and some sort of floor later. This space is for keeping my mower and other garden tools so I don't need a floor for this, at least not initially.

Are you talking about pouring concrete only into the holes?
 

Michael Armstrong

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Sparky617

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The problem with pouring concrete around your posts is PT wood is very wet when you buy it, as it drys it shrinks. This creates a void between the wood and the concrete that fills with water. You are much better off doing it as Neal suggests. I had to help my neighbor fix his deck posts last year due to this issue. I need to do my own in the near future. The builder put the posts in concrete. Also, the concrete is there to provide a footer to spread the load out. If you put the post in first the concrete isn't really doing anything as the post is resting on the ground.
 

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