OSB vs Plywood: Which One Wins?

Summary

This video compares OSB and plywood for roof decking through various tests. It evaluates nail holding, water absorption, and structural strength. Plywood wins the nail test, but OSB excels in water absorption and is less susceptible to delamination and termite damage. The video concludes that OSB is the superior choice for roof decking due to its performance in real-world applications.

Takeaways

• 📐 **Nail Holding Test**: Plywood outperformed OSB in holding nails, with an average of 77.1 lbs compared to OSB's 28 lbs.
• 💧 **Water Absorption Test**: Over 4 days, OSB absorbed only 5 oz of water, while plywood absorbed 7 oz, indicating OSB is more water-resistant.
• 🏗️ **Strength Test**: Plywood could span greater distances without breaking compared to OSB, suggesting it's stronger for longer spans.
• 🔍 **Moisture Spread**: OSB showed less moisture spread than plywood, which could be beneficial for preventing water damage.
• 🏡 **Practical Application**: The presenter believes OSB is superior for roof decking due to its water resistance and less susceptibility to damage.
• 🐛 **Termite Resistance**: OSB is less likely to be eaten by termites compared to plywood, which has more wood content.
• 🔄 **Delamination**: Plywood is more prone to delamination over time, which can lead to the need for full sheet replacement.
• 🛠️ **Construction Practice**: In real-world scenarios, small OSB sections can be replaced easily, whereas plywood damage often requires larger replacements.
• 🔩 **Nail Pull Test**: While plywood won the nail pull test, the presenter doesn't consider it a major factor due to shingles being more likely to blow off.
• 🏋️ **Weight Test**: The presenter tested the板材 by standing and jumping on them, finding both materials impressive but ultimately favoring OSB for everyday use.

Q & A

What is the main objective of the video?

The video aims to determine whether OSB or plywood is a better material for roof decking by performing various tests on both materials.

How does the presenter test the nail-holding strength of OSB and plywood?

The presenter drives three nails into both OSB and plywood samples, pulls on each nail with a scale, measures the maximum weight they can hold, and averages the results to compare the nail-holding strength of the materials.

What were the results of the nail-holding strength test?

Plywood had an average nail-holding strength of 77.13 lbs, while OSB averaged 28 lbs, making plywood the clear winner in this test.

How was the water absorption test conducted?

The presenter weighed both materials, submerged them in water for four hours, and then measured how much water each absorbed. The materials were then submerged for an additional three days before the final water absorption measurements were taken.

What were the results of the water absorption test after four days?

After four days, both OSB and plywood had absorbed 36 ounces of water, but OSB absorbed less water overall (5 oz) compared to plywood (7 oz), with the water spreading less in OSB.

Which material performed better in the water absorption test and why?

OSB performed better in the water absorption test because it absorbed less water and spread it less compared to plywood. This makes OSB more resistant to water damage.

How was the strength test for spanning capability conducted?

The presenter tested how well OSB and plywood could span distances without breaking by standing on them at increasing distances (from 16 inches to 36 inches) and observing how much cracking occurred.

What were the results of the spanning capability test?

Both OSB and plywood performed well in the spanning test, with plywood being slightly stronger as it could span wider distances (up to 36 inches) without breaking.

What does the presenter conclude about the delamination issue?

The presenter explains that plywood is more prone to delamination over time compared to OSB. If one sheet of plywood fails, the entire sheet may come apart, whereas OSB's structure limits failure to localized areas, making it more durable.

Why does the presenter prefer OSB over plywood for roofing?

The presenter prefers OSB because it absorbs less water, has better localized damage control, is less prone to delamination, and termites are less likely to target OSB than plywood.