Gable end trim, also known as rake trim, plays a critical role in finishing and sealing the edges of a metal roof. It provides a clean, professional look while protecting the roof from water penetration and wind uplift. In this guide, we will cover the complete installation process for gable trim on exposed fastener panels, including the tools required, preparation steps, installation at the eave and ridge, overlapping, fastening, and final sealing.
Tools and Supplies for Gable End Trim Installation
The following tools and supplies are essential for a smooth and precise gable trim installation:
| Tools Required | Supplies Required |
|---|---|
| Metal cutting snips | Silicone sealant (NovaFlex recommended) |
| Hand seamer | Double-sided butyl tape |
| Carpenter’s pencil | 1/4″ × 7/8″ metal-to-metal lap screws with sealant washers |
| Roofing gloves | Protective plastic film removal tool |
| Caulking gun | Neoprene closures (for ridge cap connection) |
| Protractor | 7/8″ × 3/16″ butyl tape strips |
| Speed square | Pop rivets (matching color preferred) |
| Sliding T-bevel | Ridge cap for high peak |
| Combination square | Closure sealant for ridge ends |
Preparation Before Installation
Before cutting or fastening gable trim, accurate measurements are crucial. When measuring, include an overhang of roofing panels. Generally, three inches are needed for overlaps and at least one inch is needed for ridge connections. Determine the pitch of your roof and transfer that angle to the gable trim using a speed square and T-bevel. Mark cutting lines clearly on the trim’s protective plastic coating.
During preparation, create a one-inch tab on the top side of the gable trim. This tab acts as a stiffener and should be folded downward at 90 degrees using a hand seamer. The 45-degree hem cut should align perfectly with the eave trim for a seamless fit.
Installing Gable Trim at the Eave
At the eave ends of the roof, mark three inches from the trim’s edge along the drip side, and one inch on the top side. Connect these marks to create the stiffener tab. Cut along the marked lines and fold the one-inch tab downwards. This fold helps the gable trim sit flush with the roof panel, ensuring a tight and weather-resistant connection. Repeat the same process for the opposite side.
Installing Gable Trim at the Ridge
At the ridge, mark one inch from the top side of the gable trim. Using the T-bevel set to the roof’s pitch, draw a line inward toward the drip edge. Mark a 90-degree line at the drip edge and cut away the marked section. Create a one-inch notch at the hem to allow for proper folding. Bend the topside tab downward to match the roof pitch. This ensures the gable trim fits snugly against the ridge cap.
Overlapping Gable Trim
Gable trims should be overlapped by three inches for strength and weatherproofing. Mark three inches on both hems of the trim pieces. Pry open the hems at these marks and remove the drip edge hems where necessary. Apply silicone sealant one inch from the notched side of the gable. The caulking side should underlap the second piece for a watertight joint. Smooth out excess sealant for a clean finish.
Fastening the Gable Trim
Before fastening, remove the protective plastic film from the gable trim. Place a strip of butyl sealant tape parallel to the gable along the high seam of the roofing panel. Fasten the gable trim using 1/4″ × 7/8″ metal-to-metal lap screws, spaced twelve inches on center along the high seam. Additional screws should be placed twelve inches on center along the trim’s face, staggered from the panel screws. Avoid placing screws within twelve inches of the gable peak to allow space for the ridge cap installation.
High Peak and Ridge Cap Connection
For high peak areas, measure and cut the gable trim to form a compound 45-degree miter. Leave small tabs to prevent gaps at the connection point. Test-fit the pieces before final fastening. Use neoprene closures to seal the ridge cap connection, placing them one inch back from the ridge edge. Apply sealant generously to the closures for a watertight fit.
The ridge cap should overlap the gable trim precisely, with any excess material trimmed for a tight corner. Secure the ridge cap with screws and pop rivets, ensuring all joints are sealed with silicone.
Final Touches
Once all trims are fastened and sealed, inspect the installation for gaps, loose fasteners, or missed sealant applications. Properly installed gable end trim not only improves the appearance of a metal roof but also enhances its durability against weather elements.
Hello! I’m Abdullah, a passionate professional in the field of construction and roofing. I am the proud owner of SJ Roofing & Venting, a leading construction company based in New York. With years of hands-on experience, I write about various construction methods, techniques, and industry insights to share my knowledge and help others in the field. I’m also the founder and main contributor of this website.