Building a deck is one of the best investments you can make in a Twin Falls home — our warm summers and mild springs mean you'll use it most of the year. But choosing the wrong lumber will cost you in repairs, replacement, or worse, structural failure.
The most important distinction for deck lumber is ground contact vs. above-ground treatment. Pressure-treated lumber (PT) comes in two ratings: .15 PCF for above-ground applications like deck boards and railings, and .40 PCF for ground contact or concrete-embedded posts. Using the wrong rating is a common mistake — using above-ground PT for a buried post will rot within a few years in Idaho's moisture cycles.
For decking boards themselves, you have several good options in the Pacific Northwest region. Pressure-treated southern yellow pine (SYP) is the most affordable and widely available. It requires sealing or staining within 6 months of installation. Incense cedar is naturally rot-resistant and looks beautiful — it's a premium option that many Twin Falls contractors prefer for visible decking. Redwood is the gold standard but often requires special ordering.
For structural members — joists, beams, and posts — always use pressure-treated. Period. Even in areas that won't contact the ground, moisture accumulates in structural connections and PT lumber gives you the safety margin you need.
One tip most people miss: let your PT lumber acclimate. Fresh pressure-treated lumber contains moisture from the treatment process. Stack it with spacers ("stickers") between boards and let it dry for at least a week before installation. This prevents the dramatic warping and splitting that causes so many deck callbacks.
We stock dimensional PT lumber in common sizes and can cut to length on most orders. Call ahead for large orders — (208) 555-0211 — and we can have your material ready for pickup.
Questions? We're here. Call (208) 555-0211 or visit us at 2180 Addison Ave W.