Installing Roof Jack in Shake Roof

ridgeline_dev

We are installing a radon mitigation system in our house and plan to run the pipe alongside the outside wall, and up through the soffit.

I need to add a 4" pipe jack for the vent pipe penetration. I understand how this would be done on a comp roof, but this is a cedar shake roof (which I don't have much experience with).

The pic below shows essentially what I am trying to accomplish.

Any info or tips would be greatly appreciated.

James

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Ed the Roofer

Since Cedar does not flex and bend like composition shingles, they have to be removed.

To do that, you have to go to a roofing supply house and purchase a tool called a slate nail ripper.

It is a double 90* bend on the handle and then a long flat metal shaft that slides under the shakes or tiles. The tip of it is curved and wider than the shaft. It sort of looks like a mushroom head. When the bottom portion goes past the fastener, you can hook onto the fastener with its cutting edge.

When you get it tapped in far enough under the cedar to where the nails or staples are located, you slide it sideways until you feel that it has encountered the nail or staple. Then you take a hammer and tap downward, meaning towards the gutter eave edge on the vertical portion of the handle.

You continue tapping with the hammer until the fastener either shears off from the cutting edge of the ripper, or it begins to pull it out sideways.

Continue with as many courses above the location until you have the necessary room to install the pipe flashing.

I am assuming you know how to install the flashing properly, since you referred to composition shingles and it seemed like you know what to do once you get to that point.

Ed

ridgeline_dev

Thanks Ed.

Then I assume the jack would go under the tar paper, in a similar fashion to a comp shingle.

Ed the Roofer

It would go under the shake liner felt, which is an 18" wide roll of 30# felt paper, as well as the newly installed cedar, which would need to be installed around the 2 sides of the new flashing and also on the top portion. If there are any voids or gaps when you install this, you need to install cedar starter shingles under the field cedar shakes to avoid leakage.

I also would recommend that you strip in the 2 sides first and then the top portion of the flashing with narrow 6" + strips of Grace Ice and Water Shield as an added water-proofing measure.

Ed

ridgeline_dev

Thanks for the help Ed. I think I have a handle on it now.

James