Home>Discussions>YARD & GARDEN>Decks, Patios, & Porches>4x4 post for exterior structural column that won't warp or bend
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RC123
4x4 post for exterior structural column that won't warp or bend
RC123

I need to replace an exterior porch corner post/column. The column I am replacing is on a first floor porch which has another porch above it and the second floor porch has a roof over that porch. The house is 100 years old and the existing post/column is made from four 1x6 boards nailed together to form a hollow column. I plan to put a solid 4x4 wood post inside the hollow column.
Many 4x4 posts that I have used for fencing have warped, bowed and twisted badly over time. Is there a special wood or material that I can use for this post that will not warp, bow, twist, etc.?

A. Spruce
Re: 4x4 post for exterior structural column that won't warp or bend
A. Spruce

All wood, every stick of it, will warp, twist, and otherwise turn itself into a pretzel if it is not "captured" while it is still straight. That is to say, buy the straightest 4x you can find, then get it installed before it has a chance to dry and start twisting and tweaking.

dj1
Re: 4x4 post for exterior structural column that won't warp or bend
dj1

On addition to installing new wood as quickly as possible, apply a coat of water repellent or sealant.

Most warping in exterior wood is due to wet and dry cycles leading to shrinkage.

Mastercarpentry
Re: 4x4 post for exterior structural column that won't warp or bend
Mastercarpentry

Nature abhors a straight line, and wood is a natural product. Plus today's lumber is milled for maximum product with minimum waste instead of for any other qualities. That is one point which makes old houses better; they took more care in milling the lumber back then.

On top of what has been said here already, you'll need to hand-select that post from whatever you have available to you. Look for minimal knots, only small knots, consistent and dense growth ring thickness, not heartwood, and with the grain as straight as possible throughout. Wood species matters too but you're kind of limited to what's available where you are. Some treated lumber can be had in a premium grade which is usually shipped drier and is made from better milled stock. In cases like yours it is probably worth the extra cost; a 4X4 can exhibit huge forces when it wants to twist and if solidly anchored on both ends it will demonstrate that force by warping or splitting, so anchoring is only part of the solution. The problem with premium grade lumber is that it's usually ordered and not in stock, so you can't hand-select it.

And even given your best efforts it may twist or warp anyway- that's the nature of wood- but these hints will get you your best chances.

Phil

A. Spruce
Re: 4x4 post for exterior structural column that won't warp or bend
A. Spruce
Mastercarpentry wrote:

not heartwood

I think what you meant here is not sap wood, the live, growing part of the tree that is weak. Heartwood is the center of the tree where the grain is mature and strong.

RC123
Re: 4x4 post for exterior structural column that won't warp or bend
RC123

Thank you all very much for the great advice. The lumber yard closest to me stores all it's wood outside and the wood always seems damp so I drove a bit further to a lumber yard that stores it's wood indoors and searched through the pile of 4x4s and found a perfectly straight post with no knots, etc., really nice. I installed it the same day. I installed the post yesterday and structurally it seems good, but after thinking about it overnight, I decided I am going to strengthen the spot where the bottom of the post attaches to the base. The post lands on the rim joist. I plan to put some sort of mending plates on to fasten the post to the rim joist so it can't move.

dj1
Re: 4x4 post for exterior structural column that won't warp or bend
dj1

Sounds like you're on your way to complete the job.

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