The Pros and Cons of Putting Plywood Over Purlins on a Barn
When it comes to barn construction, the choice of materials can significantly impact the structure’s longevity, functionality, and aesthetics. One common practice is putting plywood over purlins. While this method has gained popularity among builders and farmers alike, it’s essential to weigh the advantages against the disadvantages. In this article, we’ll explore the pros and cons of using plywood over purlins, helping you make an informed decision for your barn project.
Understanding Purlins and Plywood
Purlins are horizontal structural members used in buildings, particularly in roof construction. They provide support for roofing materials and help distribute the load evenly. Typically made from wood or metal, purlins are placed perpendicularly to the rafters of the barn.
Plywood, on the other hand, is a versatile and widely used building material composed of thin layers of wood veneer glued together. It’s renowned for its strength, durability, and resistance to warping, making it a popular choice for various applications, including roofing and wall sheathing.
Pros of Using Plywood Over Purlins
- Structural Support: Plywood can add significant structural integrity to a barn. When installed over purlins, it helps distribute the weight of roofing materials more evenly, reducing stress on individual purlins and enhancing the overall strength of the roof.
- Weatherproofing: Plywood acts as an excellent barrier against the elements. When properly sealed and maintained, it can prevent moisture penetration, protecting the underlying structure from rot and decay.
- Insulation Benefits: Adding plywood can improve insulation. When combined with insulation materials, it can help maintain a more stable internal temperature, which is crucial for livestock or stored goods.
- Ease of Installation: Plywood sheets are relatively easy to work with. They can be cut to fit specific dimensions, making the installation process smoother and faster compared to other materials.
- Cost-Effectiveness: Compared to some other roofing materials, plywood is often more affordable. Its wide availability and versatility can lead to savings in both materials and labor costs.
- Design Flexibility: Plywood can be finished in various ways, allowing for creative design options. Whether you’re looking to paint it, stain it, or leave it natural, the aesthetic possibilities are numerous.
Cons of Using Plywood Over Purlins
- Moisture Vulnerability: While plywood can provide weatherproofing, it’s not completely immune to moisture damage. If not adequately sealed, it can absorb water, leading to warping or mold growth over time.
- Weight Considerations: Plywood adds extra weight to the structure. If the purlins are not adequately designed to support the additional load, this could lead to structural issues down the line.
- Maintenance Requirements: Plywood roofs require regular maintenance to ensure they remain watertight. This includes periodic inspections and resealing, which can be time-consuming and may incur additional costs.
- Building Codes Compliance: Depending on your location, building codes may dictate the types of materials used in barn construction. Some regions may have specific requirements or recommendations that could limit the use of plywood.
- Fire Risk: Plywood is combustible, and in regions prone to wildfires, this may be a significant concern. Fire-resistant materials or protective coatings may be necessary to mitigate this risk.
- Cost Over Time: While plywood may be initially cost-effective, the long-term costs of maintenance and potential replacements can add up, making it less appealing in the long run.
Best Practices for Using Plywood Over Purlins
If you decide to use plywood in your barn construction, consider the following best practices:
- Choose Quality Materials: Invest in high-quality plywood that is specifically rated for exterior use. Look for options that come with a waterproof adhesive and are treated for mold and mildew resistance.
- Proper Sealing: Ensure that all edges and surfaces of the plywood are properly sealed with a high-quality sealant. This will significantly enhance its durability and resistance to moisture.
- Regular Inspections: Schedule regular inspections to identify any potential issues early. Look for signs of moisture damage or structural weakness and address them promptly.
- Consult Building Codes: Before starting your project, check local building codes to ensure compliance. This will help you avoid costly mistakes and ensure the safety of your barn.
FAQs About Plywood and Purlins in Barn Construction
1. Is plywood a good choice for barn roofing?
Yes, plywood can be an excellent choice for barn roofing due to its strength, ease of installation, and weatherproofing properties. However, it’s essential to ensure proper sealing and maintenance.
2. How do purlins support the roof structure?
Purlins provide horizontal support for roofing materials, helping to distribute weight evenly across the rafters. This prevents sagging and structural failure.
3. What are the best types of plywood for outdoor use?
Marine-grade plywood and exterior-grade plywood are the best options for outdoor use, as they are designed to resist moisture and withstand harsh weather conditions.
4. Can I use OSB instead of plywood over purlins?
Oriented strand board (OSB) can be used as an alternative to plywood, but it may not offer the same level of durability and moisture resistance. It’s essential to consider your specific needs and the environment.
5. How often should I inspect my plywood roof?
It’s advisable to inspect your plywood roof at least once a year, preferably before the rainy season, to identify any damage or wear that needs addressing.
6. What should I do if my plywood roof gets damaged?
If your plywood roof gets damaged, it’s crucial to repair it as soon as possible. Depending on the extent of the damage, you may need to replace panels or reseal them to prevent further issues.
Conclusion
In summary, putting plywood over purlins in barn construction offers both advantages and disadvantages. While it can enhance structural support, provide insulation, and contribute to weatherproofing, there are also concerns regarding moisture vulnerability and maintenance. Ultimately, the decision should be based on your specific needs, budget, and local building codes. With proper planning and maintenance, plywood can be a valuable addition to your barn design.
For more information on barn construction, you can visit this resource. If you’re interested in learning more about different roofing materials, check out this article.
This article is in the category Construction and created by farmhousebarns Team