Pressure Treated Wood for Stairs: Durability and Safety Considerations

Pressure treated wood is a popular choice for outdoor construction projects, including decks, fences, and landscaping structures. But is it suitable for stairs? The answer is: it depends. While pressure treated wood offers excellent rot and insect resistance, making it a durable choice for exterior applications, there are some important factors to consider before using it for stairs.

Pressure Treated Wood: Pros and Cons for Stairs

Pressure treated wood is infused with chemical preservatives that protect it from decay and insect damage, making it a long-lasting choice for outdoor structures. However, there are some specific considerations when it comes to using it for stairs:

Pros:

• Durability: Pressure treated wood is highly resistant to rot, decay, and insect infestation, making it a durable choice for exterior stairs exposed to the elements.
• Cost-Effectiveness: Pressure treated wood is generally less expensive than other rot-resistant materials like cedar or redwood.
• Availability: It is readily available at most lumberyards and home improvement stores.

Cons:

• Moisture Content: Freshly treated lumber can have a high moisture content, which can lead to warping or shrinking as it dries. This can affect the stability and safety of stairs.
• Slipperiness: The chemicals used in pressure treatment can make the wood surface somewhat slippery, especially when wet. This can increase the risk of slips and falls on stairs.
• Chemical Leaching: The preservatives in pressure treated wood can leach out over time, potentially affecting the surrounding environment or posing health concerns if not handled properly.
• Appearance: Pressure treated wood may have a greenish tint or uneven coloration, which may not be aesthetically desirable for all staircase designs.

When to Use Pressure Treated Wood for Stairs

Pressure treated wood can be a suitable choice for exterior stairs in certain situations:

• Ground Contact: When the stairs are in direct contact with the ground or exposed to moisture, pressure treated wood is essential to prevent rot and decay.
• High-Traffic Areas: For stairs that will experience heavy use or foot traffic, pressure treated wood offers good durability and resistance to wear and tear.
• Cost Considerations: When budget is a concern, pressure treated wood provides a cost-effective option for durable exterior stairs.

Mitigating the Cons of Pressure Treated Wood

If you choose to use pressure treated wood for your stairs, there are ways to mitigate some of the potential drawbacks:

• Allow for Drying: Allow the lumber to dry thoroughly before construction to minimize warping or shrinking.
• Apply Anti-Slip Coating: Apply a non-slip coating or use textured stair treads to improve traction and reduce slipperiness.
• Use Safer Treatments: Choose pressure treated wood with safer, less toxic preservatives, such as those labeled “UC4B” for above-ground use.
• Proper Finishing: Apply a stain or paint to improve the appearance and protect the wood from the elements.

Building Codes and Stair Construction

Building codes in the USA, such as the IRC, provide guidelines for stair construction, regardless of the material used:

• Riser Height and Tread Depth: Building codes specify maximum riser heights and minimum tread depths to ensure safe and comfortable stair dimensions.
• Handrail Requirements: Handrails are typically required for stairs with more than three risers, and building codes specify height and strength requirements for handrails.
• Guardrail Requirements: Guardrails are required for stairs with a drop of more than 30 inches, and building codes specify height and strength requirements for guardrails.

Trends in Staircase Design

Staircase design trends are constantly evolving, influencing both material choices and aesthetics.

Here are some current trends:

• Mixed Materials: Combining pressure treated wood with other materials, such as metal or composite decking, can create a visually interesting and durable staircase.
• Open Risers: Open riser staircases, where there is no vertical board between the treads, are gaining popularity in contemporary designs, creating a more open and airy feel.
• Illuminated Stairs: Incorporating LED lighting into stair risers or treads can enhance safety and add a modern aesthetic.

Conclusion

Pressure treated wood can be a suitable material for exterior stairs, offering durability and cost-effectiveness. However, it’s important to consider its potential drawbacks, such as slipperiness and chemical leaching, and take steps to mitigate these issues. By understanding the pros and cons of pressure treated wood, adhering to building codes, and incorporating current design trends, homeowners and builders can create safe, functional, and aesthetically pleasing staircases.