If you need 4x4s or other large posts, inspect them first.
Why You Should Be Careful When Selecting 4×4 Lumber
Updated on Feb. 12, 2025
It’s every DIYer’s worth nightmare, you put time and money into building that dream deck only to find months later that something’s wrong. The posts you used are starting to warp. That’s not an easy fix. Fortunately, you can prevent warped 4x4s with a little extra time when you’re buying the lumber. Here’s how to make sure you’re getting the best 4x4s for y9ur projects.
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What is 4×4 Lumber?
Every DIYer should be familiar with 4×4 lumber since it’s an essential building block of construction, most commonly used as posts in the framing of houses, sheds, and many other structures. Like most lumber, 4×4 lumber gets its name from its dimensions. Depending on the demands of your particular project, 4×4 lumber can be purchased both treated and untreated. Just keep in mind that a treated 4×4 is going to be significantly heavier.
Why You Should Inspect 4×4 Lumber
What is a peeler core?
If you need 4x4s (or any other large posts, really) inspect them first. Why? Many of them, especially 8-ft. posts, come from logs used as peeler cores used for plywood veneer, which is peeled from the logs like paper towels from a roll. That process leaves only the very center of the log.
The problem is that the center “pith” is the least stable part of the log and is very prone to twisting, splitting and bowing. This is particularly true of treated 4x4s because the treatment exaggerates the warping and doesn’t accept pressure treatment as well. Peeler-core posts are more likely to warp and twist than posts cut farther away from a tree’s center.
What are growth rings?
Centered growth rings indicate the post is made from peeler core and won’t accept pressure treatment well (right), while off-center rings mean the post is not the log’s center (left).
How to Inspect 4×4 Lumber
Examine the stack of posts at the home center and reject the posts with end grain that looks like a bulls-eye. Choose the straightest posts you can find, with the least amount of center pith.
Buying the best 4×4 lumber
When shopping for 4×4 pressure treated posts, look at the ends. You want to buy posts without a “bulls-eye” and growth rings from edge to edge. If growth rings start near the center of the post and expand outward, it’s almost certainly made from a peeler core. If the rings are off center, it’s not the log’s center. Our suggestion is to buy 10-ft. posts instead of peeler-core 8-footers and trim them to fit. And remember, perfect lumber is rare, so it’s worth taking a little extra time while shopping to find the best you can for your DIY projects.
