4x4 Posts for Screen Porch - PT or Cedar?

by Ben
(Milwaukee, WI)

I'm in the process of building a 12 x 16 screen porch. Because the floor of the screen porch will be low (about a foot high), I decided that I would run the 4x4 posts up through the deck all the way up to the header(approx 9 ft total length).

The posts are attached to Simpson post bases with a one inch standoff that sit on top of concrete piers about 2-3 inches above grade. Initially I bought and installed pressure treated 4x4's but after a week or so, most of them were so badly warped that I decided maybe cedar 4x4's were the way to go.

So I swapped out the PT posts with cedar ones. The cedar posts are much straighter, but now I'm concerned they may not last nearly as long as PT. If I stick with the cedar posts, do you think the bottoms will hold up or will they rot quickly? I live in Wisconsin so there is plenty of snow/rain.

In my area, I don't believe kiln dried PT lumber is available. Thanks and let me know if you need any additional info.

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Editor's Comments

There is nothing wrong with using cedar support posts. The posts are elevated 1" above the concrete. That will ensure the bottoms stay dry and they will last just as long given how they are elevated.

Also if you are really afraid that they are at risk of rotting, simply apply a good code of copper preservative before you set them onto the 4x4 support post brackets.

They will certainly stay straight over their lifetime.