Properly installed solar hanger bolts are the foundation of a stable, leakproof, and durable solar mounting system. Whether you’re an industry veteran or setting up your first solar array, following precise installation steps is essential for long-term system security and performance. This guide walks you through each critical phase, offering expert tips to ensure your solar hanger bolts are installed right, every time.
1. What Is a Solar Hanger Bolt?
A solar hanger bolt is a specialized, double-threaded fastener designed to connect mounting systems to both metal and timber roof structures. One end sports a coarse thread for firm anchoring into substructures—like purlins—while the other features machine threads for attaching mounting bases such as L-feet or rails.
Why choose hanger bolts for metal roofs?
Efficient, secure, waterproof installation
Excellent load-bearing strength
Corrosion-resistant stainless steel durability
2. Tools and Materials You’ll Need
Prepare the following before installation:
| Item | Purpose |
|---|---|
| Electric drill | Create pilot holes in the metal roof |
| Torque wrench | Ensure accurate tightening |
| Silicone or butyl sealant | Seal around bolt opening; prevent leaks |
| EPDM washer | Long-lasting waterproof protection |
| L-foot / mounting base | Connects the rail system to the bolt |
| Measuring tape & marker | Mark precise drilling locations |
Pro Tip: Use only stainless steel 304 or 316 hanger bolts to prevent rust and maximize service life.
3. Step-by-Step Installation Guide
Step 1: Mark Installation Points
Find roof purlins/rafters using a stud finder. Mark bolt positions along rail lines, spaced typically 1–1.2 meters apart as specified by your racking design.
Step 2: Drill Pilot Holes
Use a drill bit just smaller than the hanger bolt’s diameter. Drill perpendicular to the roof for the best fit, and clean away any metal shavings.
Step 3: Apply Sealant & EPDM Washer
Generously apply roof-grade silicone or butyl sealant around the hole. Place the EPDM washer between the bolt and the roof—a crucial barrier for long-term waterproofing.
Step 4: Install the Hanger Bolt
Screw the coarse-threaded end into the roof structure. Tighten gradually with a torque wrench; avoid overtightening. The EPDM washer should compress just slightly for an effective seal.
Step 5: Attach Mounting Bracket
Fix the L-foot or mounting base onto the upper threaded section. Align carefully with the planned rail layout, then secure with nuts and spring washers.
Step 6: Final Inspection
Check that all bolts are installed vertically and firmly. Inspect sealant coverage for gaps and wipe away any excess for a professional finish.
Installation complete! Your roof is now ready for rail and panel installation.
4. Tips for a Reliable Installation
Always check the roof thickness before drilling.
Avoid placing bolts near roof overlaps or seams.
Reapply sealant if installation exceeds 30 minutes in hot sunlight.
For coastal or humid areas, use 316 stainless steel bolts for better corrosion resistance.
5. Common FAQs About Installing Solar Hanger Bolts
1: Can I install solar hanger bolts without removing the metal sheets?
Yes. Modern bolt designs enable direct installation through roof panels, saving time and labor.
Q2: What bolt size is best for metal roofs?
Commonly M10×200 mm or M12×250 mm—choose based on roof thickness and load requirements.
Q3: How do I ensure waterproof performance?
Always use EPDM washers, quality sealant, and avoid overtightening for dependable, watertight seals.
Q4: What’s the difference between single and double-thread bolts?
Single thread—for wood rafters; double thread—best for metal purlins and higher strength needs.
6. Troubleshooting and Maintenance
| Issue | Possible Cause | Solution |
|---|---|---|
| Loose bolts | Insufficient torque | Retighten with a torque wrench |
| Water leaks | Poor seal or aged washer | Reapply sealant/replace washer |
| Corrosion | Inferior steel | Use SS304/316 hanger bolts |
Inspect your installation every 6–12 months to keep your system safe and reliable.
7. Need Reliable Solar Hanger Bolts?
Suzhou Bilateral Import and Export Co., Ltd. delivers premium solar mounting systems and stainless steel hanger bolts engineered for exceptional durability, waterproofing, and hassle-free installation.
Our product range includes:
Solar Hanger Bolts (SUS304/316)
Solar Fastener(SUS304/316)
Explore More: www.szbolts.com
Contact us for tailor-made solar roof solutions or large-scale procurement.
By installing your solar hanger bolts the right way, you protect your investment and ensure your rooftop solar system delivers years of clean, safe energy.
