Durability Against Moisture, Rot, and Insects
The main advantage of using pressure-treated lumber outdoors is its enhanced durability and resistance to damage. The pressure-treating process forces chemical preservatives deep into the wood fibers under high pressure. This protects the wood against rot, decay, and insect infestation.
Regular lumber can quickly warp, crack, and deteriorate when exposed to repeated wetting and drying cycles outdoors. Pressure-treated lumber is designed to withstand constant moisture without warping or rotting. The preservatives also make it unappetizing to wood-boring insects like termites and carpenter ants. This results in lumber that lasts significantly longer in decking, fencing, landscape projects, and other outdoor applications.
Types of Pressure-Treated Lumber
There are several different types of pressure-treated lumber available that use different preservative chemicals:
- ALKD – Alkaline copper quaternary treated wood is currently the most common. The preservative penetrates deeply for long-lasting protection.
- ACQ – Alkaline copper azole treated lumber provides good protection but uses some chemicals that can be corrosive to metal fasteners.
- CCA – Copper chromium arsenic treatment was very common in the past but is being phased out due to concerns over arsenic leaching.
- CA – Copper azole treated lumber offers incredible rot resistance. It is safe for use around plants and gardens.
When purchasing pressure-treated lumber, look for the stamp indicating the preservative type to ensure optimal outdoor performance. Consult with local building codes for any restrictions on certain chemical treatments.
Less Maintenance and Repairs Needed
Using pressure-treated lumber for outdoor projects also saves significantly on future maintenance time and costs. The durable wood holds up better and resists issues like checking, cupping, and splintering under outdoor exposure.
Regular lumber may need replaced every 4-7 years outside. Pressure-treated lumber can easily last 15-20 years or longer before replacement is needed. This means fewer repairs, less frequent staining or painting, and lower long-term costs. It’s a worthwhile investment for the enhanced longevity.
Environmentally Friendly Options
There are also eco-friendly, non-toxic pressure treatment options available for consumers concerned about exposing plants, pets, and children to harmful chemicals. Seek out preservative-free pressure-treated lumber or treatments like ACQ and CA which use more environmentally responsible chemicals than older options like CCA.
Tips for Working with Pressure-Treated Lumber
Here are some useful tips to get the most out of pressure-treated lumber:
- Wear gloves and safety glasses when cutting and drilling to avoid skin irritation from chemicals.
- Rinse off any sawdust thoroughly after construction.
- Only use compatible metal fasteners and hardware, like hot-dipped galvanized nails, to avoid reactions.
- Let the wood dry out completely before painting or staining for maximum coating adhesion.
- Expect a greenish tint to the lumber that will fade to a natural wood color over time.
Conclusion
When selecting lumber for outdoor exposed projects, pressure-treated wood provides unparalleled durability and longevity. The special preservative treatment protects against constant moisture, pests, mold, and rot. Pressure-treated lumber may have a slightly higher upfront cost but saves significantly on maintenance and frequent repairs down the road. Investing in pressure-treated lumber leads to outdoor projects that stand the test of time.
FAQs About Pressure-Treated Lumber for Outdoor Use
What are the main benefits of using pressure-treated lumber outside?
The primary benefits are enhanced durability and lifespan compared to regular lumber. The treatment makes it resistant to rot, insects, and moisture damage. This allows projects to last for decades with less maintenance.
How long does pressure-treated lumber last outside?
Typically 15-20 years or longer before replacement is needed, compared to as little as 4-7 years for untreated wood. Higher quality treatments can maintain strength and appearance for over 30 years outdoors.
Should all lumber be pressure-treated for outdoor use?
It’s highly recommended for any lumber in direct contact with the ground or exposed to the elements. Deck boards, posts, beams, joists, railings, and steps are examples where pressure-treated lumber is ideal.
What chemicals are used to pressure treat lumber?
Common options include alkaline copper quaternary (ALKD), copper azole (CA), and alkaline copper azole (ACQ). These penetrate deeply to protect against insects and decay.
Is pressure-treated lumber safe around plants and pets?
Newer CA and ACQ treatments are considered non-toxic and safe when used as directed. Avoid older CCA lumber which contains small amounts of arsenic if concerned.
Can pressure-treated lumber be painted or stained?
Yes, it must dry out completely first. Expect it to initially have a green tint that fades over several months before coating for best color results.
Does pressure-treated lumber need additional waterproofing?
No, the treatment provides internal waterproofing against rot and moisture damage. But exterior stains add extra protection and aesthetic appeal.
What fasteners should be used with pressure-treated lumber?
Hot-dipped galvanized, stainless steel, or high-quality exterior-grade screws and nails are recommended to avoid corrosion reactions.
Is pressure-treated lumber more expensive than regular lumber?
It does come at a 15-30% premium in cost. But the enhanced longevity and performance make it well worth the additional investment.