How to Repair a Rotted Rake (Barge) Board and Flash the Top Edge
Rake boards rot from the top where the roof meets the gable. Fix the flashing and the wood together, or the new board follows the old one.
- Advanced
- 4 to 8 hours per gable end
- Updated
The short answer
Repair a rotted rake board by finding why water got in, removing the roofing edge and drip edge, cutting out the rotten board back to sound wood and checking the fly rafters or outriggers behind it. Fasten a primed replacement board with corrosion-resistant nails into the framing, add a new rake drip edge over the underlayment so it covers the top edge, and reset the shingles with a 1/2 to 3/4 inch overhang.
The rake is the sloped edge of the roof along a gable end, and the rake board, also called a barge board, is the trim that covers it. It is often fastened to the ends of framing that project past the wall, called fly rafters or outriggers, and the soffit meets it from underneath. Like fascia, it sits at the edge of the roof and takes whatever water gets past the roofing.
Rake boards rot for two main reasons. The top edge is exposed where the roof deck ends, so if there is no drip edge or the shingles stop short, water runs down onto the board and soaks into the end grain. And the board often sits on its ends and its back on framing that stays damp. In the Fraser Valley, wind-driven rain pushes up the gable edge for months each winter, so rot at the lower end of the rake, near the eave, is very common.
The repair is as much about the metal as the wood. See how to install drip edge for the rake order of layers, and how to finish a shingle rake edge for the roofing side. For the matching eave work, see how to replace a rotten fascia board.
Tools
- Pry bar and cat's paw
- Reciprocating saw
- Circular saw
- Cordless drill and driver
- Tin snips
- Level and chalk line
- Tape measure
- Paint brush
- Caulk gun
- Ladder stabilizer and a long extension ladder or scaffold
Materials
- Primed rake board lumber, cedar or PVC trim to match the old profile
- Corrosion-resistant nails or exterior screws, 2-1/2 to 3 inch
- Rake drip edge
- Underlayment or ice and water shield for the edge
- Wood preservative and primer
- Lumber for sistering outriggers or fly rafters
- Exterior sealant and paint
Safety first
- Rake edges are steep and high, often two storeys up. Use a scaffold or lift if you can, and stay tied off. A ladder at a gable is one of the most common fall setups.
- Houses built before about 1990 may have lead paint on trim, and old soffit and trim materials may contain asbestos. Test before cutting or sanding.
- Keep away from power lines, which often run to the gable end of the house. Call the utility if the work is near the service drop.
- Stay out of the fall zone. Cut boards and debris drop straight down the gable.
Step by Step
Step 1: Find the rot and work out why the water got in
Press a screwdriver into the top edge, the back and the lower end of the board, and into the outriggers and sheathing edge behind it. Rot at the top means water from the roof. Rot at the bottom edge and end points to wind-driven rain and splash. Look at the roofing edge above: missing drip edge, shingles cut short of the edge, a dead valley at the end of the rake, or a blocked gutter at the corner.
Mark the rotten length and look for the nearest sound nailing point. Note whether the rot has reached the roof deck edge. If so, see how to replace rotten roof sheathing.
Step 2: Open the roof edge and remove the rake drip edge
Loosen the nails in the drip edge and the rake-edge shingles, pulling the metal back and lifting the shingles carefully so they can be reset. Shingle tabs are brittle in cold weather, so work in mild conditions and use a flat bar gently. If the shingles are old and will not reseal, plan to replace the edge course.
Step 3: Cut out the rotten board and inspect behind it
Cut through the board at a clean angle over a sound outrigger or fastening point. Use a reciprocating saw to cut nails, and pry the board away without tearing the soffit. Then check the framing behind. Soft outriggers, rotten sheathing edges or a soaked soffit should be cut back and replaced or sistered with new lumber before the new board goes on.
Coat cut ends of the framing with preservative and let them dry. If rot is widespread, reaching the wall or the roof framing, have a carpenter assess it.
Watch out: Do not lean out over the edge to reach a rotten board. A rotten rake and outriggers may not support your weight.
Step 4: Prime and cut the new board to match
Use the old board as a pattern, including the angle at the ridge and eave ends, and any moulding or rake return. Prime the front, back, top, bottom and ends before installation, and give the ends a second coat. Consider cedar or PVC trim in place of finger-jointed pine where rot has been a repeat problem. PVC needs spacing for expansion.
Step 5: Fasten the new board to solid framing
Set the board so its top edge sits at or slightly below the roof deck, so the drip edge and shingles lie flat and the water runs onto the metal, not into a gap. Fasten with 2-1/2 to 3 inch nails or screws into every outrigger or framing member, pre-drilling near the ends. Join long boards with a scarf joint centred on a fastening point, glued with exterior adhesive, instead of a butt joint.
Hold a string line along the edge to check the board is straight, and match the line of the soffit and the fascia at the eave end.
Step 6: Install the drip edge over the underlayment
At the rake, the drip edge goes over the underlayment, so wind-driven rain cannot run under the metal and into the deck edge. Nail along the top flange about every 12 inches, lapping each piece over the one below it from the eave upward, and overlapping the eave drip edge. See how to install drip edge.
In rake areas that get heavy wind-driven rain, a strip of ice and water shield along the edge under the drip edge adds a backup.
Step 7: Reset the shingles with the correct overhang
The shingle edge should stand just past the metal so water drips free of the board. A longer overhang breaks in wind, and a shorter one lets water run back onto the wood. Hand-seal any lifted tabs and cover nails. Replace any shingles that cracked during removal.
Step 8: Caulk, paint and check the gable
Sealant goes in open joints and over nail heads, not along the drip edge where water must run. Finish with two coats of exterior paint, including the bottom edge. Look for stains on the gable wall and the soffit for any further signs of leaks.
Why Rake Boards Rot
- No rake drip edge, or the drip edge was put on under the underlayment.
- Shingles cut back from the edge, leaving the top of the board exposed.
- Bare end grain at the eave and ridge ends, which soaks water.
- Wind-driven rain pushed up the gable edge, which is why the lower end fails first.
- Damp outriggers and framing, which keep the back of the board wet.
Fraser Valley Notes
Gable ends that face the prevailing southwest storms get the most wet. Gables under trees hold moisture longer and collect needles at the lower end. Plan for a rake that is well primed, covered with metal on top, and painted regularly. Check the rake edge every fall along with the gutters.
Common Mistakes
- Replacing the board without fixing the top edge. With no drip edge over the top, the new board rots the same way.
- Rake drip edge under the underlayment. Wind-driven rain is pulled under the metal and into the deck edge.
- Bare ends and backs. End grain and hidden faces soak up water and rot from the inside.
- Fastening to rotten outriggers. The new board loosens and the rot spreads.
- Shingles cut short of the edge. Water runs down the face of the board.
- Butt joints on a long rake. They open and let water in. Use a scarf joint centred on framing.
When to Call a Professional
Rake work is high, sloped and usually near the power service, so call a roofer or carpenter if the gable is above one storey, if lines are close, or if the rot has reached the outriggers, the roof deck or the wall. Working off a ladder at a gable is a common cause of falls.
A contractor can also replace the drip edge, reset the shingles and check the rest of the roof edge while on site.
Fraser Roofing does free roof inspections across the Fraser Valley, from Hope to Abbotsford. See our Fascia and Soffit service or the towns we cover.
How to Repair a Rotted Rake (Barge) Board: Questions
What is a rake board?
A rake board, also called a barge board or verge board, is the trim board along the sloped edge of a gable roof. It covers the ends of the roof framing and the edge of the deck, and gives the gable a finished look. It is like fascia on the eaves, but it runs up the slope.
Why is my rake board rotting?
Usually because water is getting onto the top edge or behind the board. Causes include a missing or badly installed rake drip edge, shingles that stop short of the edge, bare end grain, wind-driven rain and damp framing behind the board. Rot is often worst at the eave end, where water gathers.
Does drip edge go over or under the underlayment at the rake?
Over. At the rakes the underlayment runs to the edge of the deck and the drip edge goes on top of it, so wind-driven rain pushed up the slope cannot get under the metal. At the eaves the order is the opposite, with the drip edge under the underlayment. Check the manufacturer's instructions for your roof.
How far should shingles overhang the rake?
A common overhang is about 1/2 inch to 3/4 inch past the drip edge at the rake, but the shingle manufacturer sets the exact figure. The overhang lets water drip clear of the board. Too little lets water run back onto the wood, and too much leaves the shingle edge unsupported and open to wind damage.
Can you repair part of a rake board?
Yes, if the rot is limited and the rest of the board is sound. Cut out the damaged section back to solid wood at a fastening point, and join the new piece with a scarf cut. The drip edge and the cause of the rot must be fixed too, or the new section and the rest of the board will follow the old one.
Related Guides
All Roof Edges, Fascia and Soffit guides|The full How-To Library
This guide is general education. Always follow the product manufacturer's installation instructions, the BC Building Code and WorkSafeBC requirements, which take priority over anything written here.
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