Cedar Shake to Asphalt Roof Replacement — Skip Sheathing to Solid Deck
Your house has a cedar shake roof that is mossy, split and curling, you are done with wood, and you want to know what it takes to put a normal shingle roof on a deck that was built for shakes.
Cedar shake to asphalt roof replacement means tearing the shakes off, decking over the skip sheathing underneath with plywood or OSB so the shingles have a solid surface to nail to, and then building the roof: ice and water shield, underlayment, flashing, ventilation and architectural shingles. JMB Builders does it across the Twin Cities metro. The decking is the big extra line; the shakes themselves are a heavy, slow tear-off. Priced per project.
- Shakes off, skip sheathing decked over with plywood or OSB
- Decking is the big extra line vs. a shingle reroof
- Heavy tear-off, bigger dumpster, more days
- Send photos, reply within one business day
- Licensed MN contractor BC809005
Send photos and hear back within one business day — or book a free in-home estimate.
A cedar shake roof is not nailed to a solid deck. It is nailed to skip sheathing: boards run across the rafters with gaps between them so the shakes can dry from underneath. That is what keeps a wood roof alive, and it is what makes an asphalt roof impossible without a step in between. Shingles need a continuous surface so every nail hits wood and the shingle lies flat. On skip sheathing half the nails would land in air.
So the job has three parts. First the tear-off, which is heavier and slower than shingles: shakes are thick, they come off in pieces, the nails are long and the debris is a dumpster and a half for the same roof. Second the deck: plywood or OSB over the skip sheathing, nailed to the rafters through the boards, with the edges blocked, so the roof is now a solid plane. Where the skip boards are rotted, they come out first. Third the roof itself, which is a normal roof from here: drip edge, ice and water shield at the eaves and valleys, synthetic underlayment, new flashing, ventilation, architectural shingles.
Two things change with the conversion. The roof is now sealed where it used to breathe, so the attic ventilation matters more: a wood roof vented itself through the gaps, and the new roof needs soffit intake and a ridge vent to do that job. And the fascia and trim at the eave were built for the thickness of shakes; the new deck and shingles sit at a different height, so the drip edge and the gutter line are reset to it. We check both at the estimate. Some older houses have asphalt already laid over shakes from a previous owner; that is two roofs to tear off and the same deck underneath.
What you supply
- Photos of the roof from the yard, and from the attic if you can see the underside of the shakes between the boards
- Your shingle choice from samples at the free in-home estimate; heavier architectural lines look right on a house that had shakes
- Driveway space for a larger dumpster, and cars and furniture well back from the eaves on tear-off days
- A note if the attic is finished or has insulation against the roof, which changes how the ventilation is done
What JMB supplies
- Tear-off of the shakes and all nails, with rotted skip boards removed, and a dumpster sized for shake debris
- Plywood or OSB decking over the skip sheathing, nailed to the rafters, edges blocked, quoted per sheet on the scope
- Drip edge reset to the new roof height, fascia repaired where the shakes rotted it
- Ice and water shield at eaves, valleys and penetrations; synthetic underlayment over the new deck
- New step flashing, counter flashing, pipe boots and vent caps; ridge vent cut in and soffit intake opened
- Architectural shingles, the city's permit and inspection, magnet sweep, finished photos in your job folder
How it is priced: per project
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Decking: the number of sheets to cover the roof, quoted per sheet, which is the main difference from a shingle reroof
- Shake tear-off labor and dumpster volume, which are both well above a shingle tear-off
- Rotted skip boards or rafter tails found under the shakes
- Asphalt shingles already laid over the shakes, which doubles the tear-off
- Ventilation added for a roof that no longer breathes through the deck
- Fascia and gutter line reset to the new roof thickness
- The rest: squares, pitch, valleys, dormers, chimneys, access
An attic photo looking up at the shakes between the skip boards tells us the board spacing and condition, which sets the decking plan.
How long it takes
Two to three days on site for most houses: a full day for the shake tear-off and the decking, then the roof itself over the next day or two. Steep roofs and dormers add time.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Shakes on skip sheathing, sound boards
The standard conversion. Shakes off, plywood or OSB over the boards, then a normal roof. The deck line on the scope is the whole roof area in sheets.
Shakes with rotted skip boards
Where moss held water for years the boards under it are soft. Those come out and the new deck is nailed to the rafters with blocking at the gaps. Found during tear-off, quoted per board.
Asphalt already over the shakes
A previous owner laid shingles over the shakes with a layer of felt. Both come off; two roofs of debris and the same skip sheathing underneath. The heaviest tear-off we do.
Shakes to metal instead of shingles
A standing-seam or steel panel roof over the same new solid deck. Right for a lake cabin or a house that wants the look of a lifetime roof. Covered on the metal roof page.
Cedar Shake to Asphalt Roof Replacement — Skip Sheathing to Solid Deck: questions, answered
Can you put asphalt shingles over cedar shakes?
It has been done, and it is a bad roof. The shakes are uneven, so the shingles never lie flat; the nails have to find the skip boards through the shakes, so many miss; and the shakes keep rotting underneath. The code allows shingles only over a solid deck. The right conversion is shakes off, decking over the skip sheathing, then the roof. If your house already has shingles over shakes, both layers come off.
Do I need new plywood to go from cedar shakes to shingles?
Yes. Shakes sit on skip sheathing, boards with gaps between them, and shingles need a continuous deck so every nail hits wood. Plywood or OSB goes over the boards, nailed through to the rafters, with blocking at the edges. The decking is the main cost difference between a shake conversion and an ordinary shingle reroof, and it is quoted per sheet on the scope.
How much more does a cedar shake roof cost to replace than a shingle roof?
The extras are the decking over the whole roof, a heavier and slower tear-off, a larger dumpster and usually an extra day. Rotted skip boards and any asphalt laid over the shakes add more. We do not put dollar figures on a page; the scope lists each of those as its own line so you can see what the shake roof added to an otherwise normal reroof.
Will my attic ventilation change when the shakes come off?
Yes, and it has to be planned. A shake roof breathes through the gaps in the skip sheathing; a shingle roof on a solid deck does not. Without soffit intake and a ridge vent, the attic that used to dry itself will trap moisture, and in Minnesota that means frost on the nails in winter and ice at the eaves. We open or add soffit vents and cut in a ridge vent as part of the conversion.
Is a cedar shake roof worth keeping or re-shaking?
If you love the look and will maintain it, a new shake roof is a fine roof, and we will say so. Most homeowners calling us are done with the moss, the split shakes, the sparks worry and the insurance questions, and want a roof they do not think about. Architectural shingles in a heavier line or a metal roof both go on the same new solid deck. Once the deck is on, the choice of roof is yours.
What happens to the gutters and fascia when the shakes come off?
Shakes are thick, so the old roof edge sat high and the fascia and gutters were set to it. The new deck and shingles come in at a different height, so the drip edge is reset and the gutters are rehung or replaced to meet it. Fascia behind an old shake roof is often rotted where moss held water at the eave; it is replaced before the new drip edge goes on, quoted per foot.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners, builders and dealers. Counts come straight from our job log; no customer names.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-333-4066.
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Read morePage reviewed October 2, 2026 · JMB Builders LLC, MN license BC809005 · All roofing pages
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