Wrapping 4x4 Post with 1x6 for Deck Post?

by Justin Leonard
(Holly Springs, NC)

I am building a pressure treated deck and want white painted posts and railing with the look of real wood. I understand 4x4 and especially 6x6 have issues with checking and otherwise deforming after they dry out. And no one near me sells kiln dried after treatment 4x4 or 6x6.

Is it a good idea to just build my own 6x6 in a sense by wrapping a 4x4 with 1x6 on each side (I'd miter 45 degree angles to hide unfinished sides)?

Or will the seams created by the wrap cause problems even if proper caulking and paint are used? If this isn't a good idea, what's the best way to get white posts like this since it seems quite popular?

Editor's Comments

There is a tendency for treated posts, both 4x4 and 6x6 to crack or check over time. This depends on the species of wood and even the way the lumber has been milled relative to the grain direction. Quarter sawn posts are less common but tend to be more stable. Flat sawn posts with the center of the log in the center of the post are more likely to split and check over time given the tension inside the wood and the grain radiating outwards around the periphery of the post.

Add to this large growth rings and you can end up with a perfect storm for splits, checks and the rest of it.

Adding 1x6 Veneer To Posts

This is a great idea in theory but to make it look good and last requires perfect execution. The joinery techniques at the corners will be critical. The miter joints at the corners will tend to pull apart overtime given the weather changes. So you would need to use 1x6 that is preferably quarter sawn for best grain stability. You would also want to maybe use a biscuit style of joint or other similar mechanical system. You could groove the mating faces of the miter cut and then custom cut a long strip 36" or longer with glue to slide into the groove and physically lock the corner joints together.

But all of this is a lot of work and you really have to be meticulous perfectionist to get it right.

Engineered Lumber Choices

There are two great manufacturers I can think of that make engineered posts with hollow cores in the sizes you mentioned. I am thinking of Quattro Post and Yella Wood Products.

Take a look at the quality of the select lumber chosen to make each post. It is exactly the grain pattern and milling techniques I mentioned and it is factory made for consistency. Why not just use something like this?

Difference In Assembly Techniques

The Yella Wood post uses a standard butt joinery technique whereas the Quattro Post uses a proprietary rabbet joinery. I am a bit partial to a rabbet joint especially when factory made but I have no reason to believe the Yella Wood products do not perform exceptionally well also. So there you go.

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