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Need a little cedar shake install advice, nice job want to do it right

2864 Views 4 Replies 2 Participants Last post by  tombeck
Hey guys (and gals),

Couldn't remember my password on the normal account (forgot pwd email not coming through) so had to make a new one.

This is a bit long of a read but I'm just giving as much detail as possible. Skip to section 2 if TLDR.

I'm a handyman and generally do interior remodeling and murals. However, I've gotten some nice jobs along one street in an upscale suburb near Portland and one job has turned into another and I've been in different homes on this street for over a year solid and I've probably got 2 or even 3 more years of projects on this same street if they stay patient - maybe more. So far people are just taking my not particularly competitive bids and haven't had much hard negotiation, but I'm not making more than usual money because of my slow speed, mistakes, and the extra matierals I use. But because of that the quality has been so high the clients are referring me to each other. Plus I dress button-up and clean clothes each day, so they don't mind me around their homes and kids.
I've had periods of painful no-work, so I am lucky as can be and I know it and I'm only doing my very best work here even if it takes me longer because it keeps the ball rolling if you know what I mean.

I refused their requests for concrete work several times because I just had no clue, but eventually relented and it turned out pretty well... so now at this point these kind folks seem to think I can do anything?

So this is how I ended up going from kitchens and murals to being on the roof for my first time. I'm doing the work slowly and cautiously... I'm overbuilding just in case because I don't like being on the roof, but I'd be proud as can be if I can get 50 years out of this roof.

This house is 15 years old, builder doesn't have the best reputation.

House is on a park with giant cedar trees all behind it so the roof is constantly covered in flat cedar needles.

- Whole house is skip sheathing EXCEPT the sunside/roadside, which is all solid plywood. Sunside is the complicated part of the roof, so I'm assuming it's structural so leaving it plywood and using Cedar Breather.

- Tore off the old tar paper found lots of dry rot, so tore off plywood and found critter insulation. Replaced insulation and plywood.
- Extended eave overhand for better roadside appeal and ventilation.
- Rebuilt the eave-onto-roof overhangs where the builder had gutter open end dumping at the joint of w-valley and overhang, where it sat under the eave overhang and ran down the roof 10' or so along that same overhang. That's where all the rotten plywood was (and critters, as available moisture).

- I installed permanent anchors at the ridges for safety.

- I've put Grace I&W over the entire plywood surface. with 8" overlaps, double overlap layer in the valleys and ridges, and ran the I&W 6" up the adjoining walls.
- I've flashed out the roof to wall sections using double flashing, as in flashing over the I&W and then will flash over the exposed shingle a few inches.

Section 2
Here's where my questions start, and thanks for your patience:

They want their roof to be worry free for as long as possible (I put in the permanent anchors so it would be easy to blow the cedar needles off). They have been willing to pony up for extra longevity as they are young and intend to live their lives here.

o Customer is using Jumbo-size treated Certi-last #1 split shakes. They are $360 per square my cost (but I don't upcharge, I show them the receipts) and very fine quality. I'm hand driving stainless.

o Customer is having me form and install copper w-valley, copper ridge, and copper strips occasionally along the roof, and then copper gutters later on.

o Customer does not want the 1 box-style vent that was there to be reinstalled, as it is visible from roadside and not attractive. There is 1 toilet vent pipe on this side of the roof that has to stay.

So I've put down the Grace over the entire decking, and flashed it.

1 =?= How do I install venting if the customer doesn't want the box style vent on the sun-side of the roof? Will extra box-style along the back of the house suffice? Would ridge vents work? They'd have to be on rising ridges because there is very little actual horizontal ridge at the top. This roof is all hips and valleys. If ridge-vents will work, should I not cut the plywood along the rising rafter ridges as they are probably structural? There is available ridge venting along the top ridge where the plywood meets skip sheathing, but I'm concerend that may not be sufficient.

My own solution:
I was considering adding another "sewer vent pipe" where the old box vent used to be. The pipe would be copper encased and I'd build a wide cone cap with screen for it to prevent rain entry, but wouldnt extend any depth beneath the decking... it'd just be an imitation box vent and I bet that would fly -- if it would work???
I'd have to copy the look for the other one, but just make it more vent-friendly without screen.

2 =?= Normally it appears people use 24" shakes with 10" exposure for 4" headlap. But wasn't that overlap designed to work with skip sheathing 1x6? We're over plywood here.
Since this is on plywood decking on the visible side of the roof, is there an advantage to reducing the exposure to 8" or even 6"?
8" would give me 8" headlap or a full triple layer.
6" would give 12" headlap or a full quadruple player. It'd double material cost but not double labor...
It's more material and weight but if it gives substantially longer roof longevity they'll go for it.

If I'm increasing overlap, do I no longer need 30# felt? Don't forget I put I&W on the whole surface.

3 =?= I'm putting Cedar Breather down over the entire plywood surface directy over the I&W shield so these sunside shakes last as long as possible.
? Can I double the CBreather? My concern is compression when walking on it - but if the roof has 2, 3 or 4 layers of Jumbos that's not a concern anymore.

The Cedar Bureau manual I'm going by, on page 3 figure 3, shows you can put shakes down without tar paper as long as the eave edges are protected, and this gives the shakes extended lifespan.

My understanding is this is the old-school style - but I'm afraid to mix and match new materials with old design.
Since I've protected the entire roof with I&W, and vented with CBreather, will the roof still be solid, but longer lasting if I don't use the tar paper?

4 =?= Later on the the sides of the house where there is skip-sheathing, I was planning to use the same construction method as the plywood (full I&W, CBreather then either 30# felt with 10" overlap or no felt with extra overlap), but want your input on that.

Virtually no snow here, not much driven rain either and the house is very sheltered with cedar trees on the windy side.

Anyways I appreciate your time and help, truly do, as I'm a bit out of my league but doing my best here. Work is work and can't turn down good jobs. Thank you!
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Well we decided to do 7" exposure because of this case-study, which will give us 3 ply shingle coverage with a little extra header:

I still don't know about the interlayment, or additional ventilation... but these guys have very nicely explained process:
They are shakes, Tom. Copper River out of BC. #1 premium resaw shakes, treated, jumbo. Most are pretty good but some dont have enough rings per inch to feel good about.
Then you need to utilize a liner.....#30 - 18".....NRCA steep manual lays it out.....Not rocket science.
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