Roof Trim · Metal building trim guide
Metal Roof Rake Trim (Gable Trim) for R-Panel and PBR
Rake trim covers the sloped gable edges of a metal roof, sealing the panel edge and finishing the end of the building.
Also called: gable trim, sculptured rake, rake flashing, gable flashing, rake edge trim
Metal roof rake trim is the trim that runs along the sloped edges of a roof at the gable ends, from the eave up to the peak. It caps the outside edge of the last roof panel so wind cannot peel it up and rain cannot blow in sideways.
Below we cover where rake trim goes, which size and color to choose, a simple formula with a real worked example, and step-by-step install tips. Whether you are a contractor or a homeowner finishing a carport, barn or shop near Houston, this will help you order the right amount the first time.
What Is Metal Roof Rake Trim?
Rake trim, also called gable trim or a sculptured rake, is a bent piece of sheet metal shaped like an upside-down L (often with a few extra bends for looks and stiffness). The top leg lies on the roof panel. The side leg comes down over the end wall or the gable framing.
It does four things. It seals the cut or open edge of the panel against blowing rain. It holds the panel edge down in high wind, which matters on the Gulf Coast. It closes off the gap so birds and wasps cannot get in. And it gives the gable a straight, finished line.
Where Rake Trim Goes on a Metal Building
On a gable building, rake trim runs up both sloped edges at both ends, so a normal barn, carport or shop has four rake runs. On a single-slope roof such as a lean-to or shed roof, there are two rake runs, one on each side, running from the low eave to the high side.
On an open carport the rake side leg covers the end bow or truss. On an enclosed shop it laps down over the top of the end wall panels, closing the joint between roof and wall.
Rake Trim Sizes, Gauge, Profile and Colors
Rake trim for R-panel and PBR is typically 26 gauge to match the roof panel, and 29 gauge versions exist for light carport work. It comes in bare Galvalume or painted colors. Many owners pick a trim color that contrasts with the panel, such as light panels with darker trim.
The top leg is sized to cover the last major rib of the panel, so the trim needs to match your panel profile. Plain rake and fancier sculptured rake shapes are both common. Pieces are typically 10 ft long; ask us about lengths. If you are replacing old trim, send a photo of the end of the old piece with a tape measure on each leg and we can have a custom bend made.
How to Measure Rake Trim and How Many Pieces to Order
Formula: slope length = half the building width x the pitch factor, plus any eave overhang. Multiply by the number of rake runs (4 for a gable, 2 for a single slope). Pitch factors: 1:12 = 1.00, 2:12 = 1.01, 3:12 = 1.03, 4:12 = 1.05, 6:12 = 1.12.
Worked example: a 30 x 40 gable building with 12 ft walls and a 3:12 pitch. Half the width is 15 ft. 15 x 1.03 = 15.5 ft per run. Four runs = 62 ft. Add 10% = 68 ft, which divides out to 7 pieces of 10 ft trim.
But look at each run. A 15.5 ft run takes one full piece plus about 6 ft of a second piece once you allow for the lap. The roughly 4 ft left over is too short to finish the next run. So for this building, order 8 pieces, two per run. Always check runs one by one on rake trim; the 10% rule alone can leave you short.
How to Install Rake Trim on a Metal Roof
Rake trim goes on after the roof panels and usually after the eave trim, and before the ridge cap. Plan the panel layout so the panel at each gable ends on a full rib for the trim to sit on.
- Lay a strip of butyl tape along the top of the last panel where the rake top leg will sit.
- Start at the eave. Line the first piece up with the eave trim, notch or fold the bottom end so it closes neatly, and keep the trim straight with a string line.
- Fasten the top leg down into the panel rib with #14 x 7/8 in. lap (stitch) screws about every 12 inches.
- Fasten the side leg into the end wall panel, girt or end frame about every 12 to 24 inches, depending on the building.
- Work up the slope so each upper piece laps over the lower one about 2 to 4 inches, shingle style, with sealant in the lap, so water runs over the joint and never into it.
- At the peak, cut and fold the two rake pieces so they meet cleanly, then let the ridge cap overlap the tops. Seal the joint with butyl or sealant.
Common Rake Trim Mistakes to Avoid
- Starting at the peak and working down, which laps the joints backward so water runs into them.
- Ordering by total footage only and coming up short because leftover pieces are too short for the next run.
- Forgetting the overhang when measuring slope length.
- Ending the roof on a cut panel flat with no rib for the trim to sit on.
- Spacing screws too far apart, so the trim flutters and loosens in strong wind.
- Skipping butyl tape under the top leg.
What to Order With Rake Trim
Rake trim is ordered together with the rest of the roof edge trim. A typical gable roof trim list includes:
- Ridge cap bent to your roof pitch.
- Eave trim or gutter for the low edges.
- Outside corner trim if the building is enclosed.
- Butyl tape and color-matched #14 lap or stitch screws.
- Touch-up paint to match your trim color.
Get Metal Roof Rake Trim in Houston From Ironrod Steel
Ironrod Steel Co. rolls its own R-panel and PBR roofing and supplies matching rake trim, ridge cap, eave trim, foam closures and screws. Give us your building width, length, wall height and roof pitch, or just send photos, and we will work out how many pieces you need. Pick up at 8122 Hillsboro St in Houston or ask about delivery across Houston and Southeast Texas. Call or text (281) 902-7619.
Rake Trim FAQ
What is the difference between rake trim and eave trim?
Rake trim runs along the sloped edges of the roof at the gable ends. Eave trim runs along the low, level edges where the water runs off. A gable building needs both.
Which way should rake trim lap?
Start at the eave and work up toward the peak, so each upper piece laps over the lower piece. That way water flows over each joint instead of into it. Put sealant or butyl in every lap.
How many pieces of rake trim do I need for a 30 x 40 building?
With a 3:12 pitch and no overhang, each of the four rake runs is about 15.5 ft. That needs two 10 ft pieces per run, so plan on 8 pieces. Overhangs or a steeper pitch can change that, so check each run.
Is rake trim the same as gable trim?
Yes, the names mean the same piece. You may also hear it called rake flashing or sculptured rake, depending on the shape and the supplier.
Do I need closures under rake trim?
Usually not on R-panel or PBR, because the panel ribs run parallel to the rake edge. The trim sits on the last rib with butyl tape under it. Closures are used at the eave and ridge, where the ribs end.