What kind of plywood for outdoor climbing wall?

Climbing walls have become increasingly popular for outdoor spaces. They provide a fun activity for kids and adults alike. When building an outdoor climbing wall, using the right materials is crucial for safety and durability. One of the most important decisions is choosing the right type of plywood.

What are the options for outdoor plywood?

There are a few main options when it comes to choosing plywood for an outdoor climbing wall:

• Marine grade plywood
• Exterior grade plywood
• Pressure-treated plywood
• Cedar plywood

Each type has its own characteristics that make it suitable or not for outdoor climbing walls.

Marine Grade Plywood

Marine grade plywood is designed to withstand prolonged exposure to moisture and the elements. It uses waterproof glue and has fewer defects and voids compared to other plywood grades. The layers are also thicker and bonded with weather resistant adhesive.

Marine plywood is commonly used for boat building, but it can also be an excellent choice for outdoor climbing walls. The water-resistant construction prevents delamination, cracking, and rotting.

Exterior Grade Plywood

Exterior plywood is manufactured with fully waterproof adhesive. It is designed to be used in applications where moisture exposure is expected. Although not as robust as marine grade, exterior plywood is treated to better handle humidity and dampness.

For climbing walls, exterior plywood can be a more affordable option compared to marine grade. It provides good resistance against moisture damage.

Pressure-Treated Plywood

Pressure-treated plywood is infused with chemical preservatives that help protect it from insect damage and rot. The preservative chemicals are forced deep into the wood under high pressure.

This plywood is commonly used for general outdoor construction projects. It provides decent protection when used for climbing walls. However, the chemicals may be abrasive on skin over time.

Cedar Plywood

Cedar is a naturally decay-resistant softwood. It contains oils that act as natural preservatives. Cedar plywood retains these protective oils, allowing it to better withstand outdoor exposure.

Although not as durable as marine grade, cedar plywood can be a good eco-friendly option. It is naturally resistant to moisture, decay, and insects.

What are the key considerations?

When selecting plywood for your outdoor climbing wall, there are a few important factors to consider:

• Moisture resistance – The plywood must be able to handle rain, snow, and dampness without warping, delaminating or rotting.
• Durability – It needs to stand up to wear and tear from climbing without splintering or cracking.
• Knots and defects – Less defects means greater strength. Knot-free plywood is best.
• Surface finish – A smooth sanded surface helps ensure good grip for climbing.
• Strength and rigidity – The plywood should be thick enough to resist flexing and support screws.
• Cost – Higher grades cost more but provide greater quality and longevity.

What thickness of plywood is best?

For outdoor climbing walls, a plywood thickness of 3/4 inch (19 mm) or 1 inch (25 mm) is recommended. Here is an overview of common plywood thicknesses and their suitability for climbing walls:

Thickness	Description	Recommended?
1/4 inch (6 mm)	Too thin and flexible for climbing walls	No
1/2 inch (12 mm)	Prone to flexing under body weight	No
3/4 inch (19 mm)	Provides good rigidity for climbing	Yes
1 inch (25 mm)	Very rigid and strong for climbing	Yes

While 1/2 inch plywood may work for small walls, 3/4 inch and 1 inch thicknesses are best for full size climbing walls. The added rigidity prevents flexing and bouncing while climbing.

What grade of plywood is best?

For outdoor use, you generally want an Exterior grade plywood at a minimum. The two main grades to consider are:

Exterior Grade

Exterior grade plywood uses adhesives capable of withstanding occasional moisture. It is suitable for areas protected from continuous direct weather exposure. Exterior grade offers decent durability at a moderate cost.

Marine Grade

With waterproof adhesive and higher quality veneers, marine grade plywood can handle direct, long-term outdoor exposure. Although more expensive than exterior grade, marine plywood provides superior resistance to delamination and decay.

The ultimate grade will depend on your specific needs and budget. Marine grade is ideal if maximum weather resistance is needed. If cost is a concern, exterior grade can still perform well with proper sealing and maintenance.

What are the pros and cons of different plywoods?

Here is a comparison of the advantages and disadvantages of common plywood types:

Plywood	Pros	Cons
Marine Grade	Maximum moisture and weather resistance Prevents delamination and rotting Long lifespan with outdoor use	More expensive than other grades
Exterior Grade	Good water resistance More affordable than marine grade	Not as durable as marine grade Lower resistance to rot and decay
Pressure-Treated	Treated to resist rot and insects Commonly available	Chemicals may be harsh on skin Prone to moisture damage
Cedar	Naturally decay resistant Eco-friendly option	Less rot resistance than marine grade On the expensive side

When comparing plywood for outdoor walls, marine and exterior grades have the best combination of moisture resistance, durability, and cost. Pressure-treated plywood can work but is not ideal for prolonged direct weather exposure and climbing. Cedar provides a nice natural option but doesn’t offer the same level of decay resistance as marine grade.

What are the recommended plywood brands?

When selecting plywood, going with a reputable brand is advised. Here are some of the top plywood manufacturers recommended for outdoor climbing walls:

• BCX Plywood – Known for durable exterior and marine grade plywood good for outdoor use.
• Plum Creek – Produces weather and decay resistant plywood, including cedar grades.
• States Industries – Offers reliable exterior plywood at various thickness and sizes.
• Weyerhaeuser – Manufactures exteriorgrade plywood sanded smooth on both sides.
• Georgia-Pacific – Known for Durastrand plywood with strong water resistance.

Going with plywood made by established brands like these can give you confidence in the quality and construction. Avoid cheap plywood from unknown manufacturers.

What kind of plywood is used for climbing walls?

The most common and recommended type of plywood for climbing walls is marine grade. Marine plywood offers the following advantages that make it well-suited for climbing:

• Uses durable, waterproof adhesive that won’t delaminate
• Resists rot, decay, and moisture damage
• Made with high-quality veneers that reduce splintering
• Doesn’t easily warp or bend under body weight
• Handles regular wear and tear from climbing shoes
• Sanded smooth finish provides good grip

While marine grade is often considered the gold standard, less expensive exterior plywood can also be used if properly sealed and finished. Pressure-treated and cedar plywood are other options with some trade-offs. But for maximum durability and safety, marine grade plywood is the top choice.

What should the plywood be finished or sealed with?

Even with moisture-resistant plywood, it is advisable to apply some type of protective finish or sealer. This provides an added layer of waterproofing and durability. Here are some good options:

• Spar urethane – Provides maximum protection against moisture while remaining flexible and resistant to scratches.
• Epoxy resin – Offers an extremely durable and moisture-impervious finish for climbing walls.
• Polyurethane – Water-based polyurethane is easy to apply and maintains the natural wood look.
• Exterior paint or stain – Stain gives protection while showing off the wood grain. Paint provides a opaque protective barrier.

Be sure to follow the manufacturer’s recommendations for proper application and drying time. A finish will help the plywood last longer and also provide a smooth climbing surface.

What are the steps to build an outdoor plywood climbing wall?

Building a plywood climbing wall in your backyard is a fun DIY project. Here are the basic steps involved:

1. Design and plan – Sketch out wall size and shape based on space available. Decide on difficulty and climbable area.
2. Obtain permits – Get any required building permits based on wall height and location.
3. Clear area – Remove any plants or obstructions where the wall will be built.
4. Prepare foundation – Create a level, packed gravel base for the wall to sit on.
5. Install support posts – Secure vertical 4×4 posts into the ground to attach the plywood to.
6. Attach plywood sheets – Use 3/4″ or 1″ exterior plywood, spaced slightly apart for drainage.
7. Add climbing holds – Drill and bolt colored plastic climbing grips onto the plywood at varying angles.
8. Finish surface – Apply spar urethane, epoxy, or other sealant to waterproof the wall.

Safety gear like helmets, harnesses and padding should be used. Be sure to follow all building codes and get expert help if needed. With the right plywood and technique, you can create a backyard climbing wall the whole family can enjoy.

Conclusion

Choosing the right plywood is crucial when building an outdoor climbing wall. Marine grade offers the best durability and moisture resistance. But less expensive exterior grade plywood can also work well if properly finished and maintained. Aim for 3/4 inch or 1 inch thickness for maximum rigidity. Apply a protective sealant to waterproof the wall. With the proper plywood and construction, you can build a safe, fun backyard climbing wall for kids and adults to enjoy.