That's a very common and valid concern! Splinters on a garden bench can definitely turn a relaxing moment into an unpleasant one. Let's talk directly about treated lumber and smoothness.
The short answer is: Not inherently, but it can be. The treatment process itself—typically pressure-treating with preservatives—does not automatically make the wood smoother. In fact, freshly treated lumber (often called "green" treated wood) can sometimes feel even rougher or have a damp, coarse surface. The real difference lies in the finishing potential and durability.
Here’s the breakdown:
* The Reality: Treated lumber is prized for its resistance to rot and insects, not its surface feel. When it arrives from the yard, it may have mill marks, raised grain, and small cracks called checks.
* The Key is Preparation: Treated lumber *accepts smoothing* very well. Its durability means you can sand it aggressively without as much worry about compromising soft wood. Proper sanding is your #1 tool against splinters.
* The Finish Makes it Smooth: Applying a sealant, stain, or outdoor-rated paint after sanding is what creates that smooth, splinter-resistant barrier. This finish locks down wood fibers, preventing them from lifting and becoming splinters.
So, what should you do?
1. Choose Kiln-Dried After Treatment (KDAT) lumber if available. It's more stable and often smoother to start.
2. Sand, sand, sand! Start with a coarse grit (80-100) to level the surface, then progress to a finer grit (150-220) for smoothness. Always sand *along* the grain.
3. Apply a Quality Finish. A penetrating oil-based sealant or a solid stain will soak in and protect the wood, maintaining that smooth feel for seasons.
For an existing bench giving you splinters, don't replace it just yet. Give it a good sanding and a fresh coat of finish. That will likely solve your problem and restore your bench to a safe, comfortable seat for enjoying your garden.