# Using Felt with Cedar Shakes



## Ed the Roofer (Jan 27, 2007)

This guide from the Cedar Shake and Shingle Bureau should help you with your questions.

http://www.cedarbureau.org/installation/roof_manual/page04.htm

Yes, for Cedar Handsplit Shakes, you absolutely do need to install interply 18" shake liner 30# felt between the courses.

Ed


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## skymaster (Jun 6, 2007)

http://www.graceathome.com/pages/downloads/ForRoofs_Brochure.pdf
http://www.benjaminobdyke.com/html/products/cedar.html


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## Ed the Roofer (Jan 27, 2007)

You will not be needing the Cedar Breather product under your new shake roof if you intend on leaving the spaced board skip sheathing with the gaps in between the boards.

I understood your pos to mean that you would only be filling in some gaps where the cedar nailing pattern will fall on.

Ed


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## skymaster (Jun 6, 2007)

Oooooooops I is in trouble again!:yes: missed the "spaced sheathing" havent seen it in so many years brain automatically goes to plyywood of osb. I bad


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## freddmc (Mar 8, 2008)

Ed said;
"You will not be needing the Cedar Breather product under your new shake roof if you intend on leaving the spaced board skip sheathing with the gaps in between the boards.

I understood your pos to mean that you would only be filling in some gaps where the cedar nailing pattern will fall on."

Ed, you are correct about "filling in the gaps" ONLY where the nailing pattern requires it.

So do I interprete your answer to say that " I don't need any felt at all-just nail on the shakes or are you saying a product such as Cedar Breather is NOT necessary but you do still NEED felt?

Thanks

Fred McNeill


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## skymaster (Jun 6, 2007)

F E L T for sure. Read the cedar industry link FELT under shakes on skip sheathing


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## Ed the Roofer (Jan 27, 2007)

freddmc said:


> Ed, you are correct about "filling in the gaps" ONLY where the nailing pattern requires it.
> 
> So do I interprete your answer to say that " I don't need any felt at all-just nail on the shakes or *are you saying a product such as Cedar Breather is NOT necessary but you do still NEED felt*?
> 
> ...


 
Yes, you absolutely need the "Shake Liner" felt.

No to the Cedar Breather, since the spaced board skip sheathing will provide the necessary underside ventilation to dry out the shakes after they get wet.

Cedar Breather is a product which provides a breating space underneath the entire roof system. Shakes need to breathe from air flow underneath them to not remain wet, which will deteriorate, crack and alow them to bow to easily.

Ed


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## Dale Chomechko (Mar 11, 2008)

*Felt & Cedar Breather*



freddmc said:


> On another thread in the contractors forum there was a discussion about using felt with cedar shakes. Some felt it may not been necessary.
> 
> In my case I am re-roofing my roof with a 4/12 pitch. It has 20 year old 24 inch cedar shakes(split on one side and sawn on the other) The underlay is not solid sheeting but rather is spaced sheeting. On top of the sheeting is felt paper (with about 6 inch overlap).
> 
> ...


Hi Fred 
I have manufactured & installed shakes most of my life(36 years in the field)
Yes you can install shakes without felt as they used to for 500 years. The shakes have to be triple coursed, not double coursed like they do today(cedar shingles are triple coursed & do not require felt except for starter)
The problem tends to be cost of materials needed to acomplish this.
Cedar Breather as I see it is only effective under a triple coursed application on plywood, otherwise it really has no way to breathe. especially in 18" applications where it actually has 2 layers of felt on top. Good gimmic but hardly practical
Dale


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## tinner666 (Mar 14, 2005)

My concern would be the 4/12 pitch. Kinda low, IMHO.


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## johnk (May 1, 2007)

Felt,felt,felt as Ed says.Shakes arent the same as they were 50 yrs ago for one and why not have the extra protection and its code where I come from:no:


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## Ed the Roofer (Jan 27, 2007)

I would be extremely cautious, and make sure I use the felt shake liner, especially in view of the low pitch.

Shakes on a 4/12 pitch st as long as on a steeper pitch, especially if you are in a snow region, where it will soak up moisture and start to bow, and split. Cedar shingles, since they are applied in a 3-ply coursing, which is standard, will probably last longer, but thet too wil start to bow from retaining moisture prematurely.

Ed


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## Dale Chomechko (Mar 11, 2008)

*Bowed Shakes*

Bowed shakes(especially 5/8 Tapersawn-18" or 24") are usually a result of something called cross grain. Picture a knot in a tree, the grain curls around this knot. the grain is crossing the side(not the face)of the shake.As this shake dries, on the face first, it starts to curl up & as time goes on it gets worse. Eventually snapping off. This is a #4 shake. This is not a #1, basically you have been ripped off because so few people know the grading rules. A split shake is not subject to curling because you are not sawing through this bad grain. Even a resawn shake is first naturally split & not subject to this. 
The very best way to protect your roof from rotting even if it stays wet underneath is to get it pressure treated from the manufacturer. I have yet to see rot on these roofs & I've seen lots of 30 year old roofs & oh ya, I live in a rain forest


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## webbyonweb (Apr 26, 2009)

*Synthetic Underlay ?*

I have manufactured & installed shakes most of my life(36 years in the field)


Hi Dale, I'm curious if you have an opinion on using synthetic underlays such as GAF Deck Armor instead of felt ? It's a superior breathing product, is much stronger, tear resistant etc, ease of install etc . . . your thoughts and experience would be appreciated . . thanks, Eric


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## Dale Chomechko (Mar 11, 2008)

*Deck armour*

Hi Eric
Deck Armour does breath very well. I had an experience with it that totally amazed me. A mastic was used underneath it in this case & a piece of EPDM rubber overlapped it (dead valley /hip intersection-it was goofy)
the mastic fumes actually leached through the Deck Armour & buckled the EPDM proving to me its breathing capabilities.
Also I have seen Deck Armour protect a renovation for 3 months without leaking.I live in BC -150 inches of rain 
Need I say more, it's a very good product.
You would still have to cut it into strips & layer it between each row of shakes.
If this is new construction or being inspected you may want to check with the inspector (try to get something in writing)
Dale Chomechko
DC Roofing Inc


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## Dale Chomechko (Mar 11, 2008)

freddmc said:


> On another thread in the contractors forum there was a discussion about using felt with cedar shakes. Some felt it may not been necessary.
> 
> In my case I am re-roofing my roof with a 4/12 pitch. It has 20 year old 24 inch cedar shakes(split on one side and sawn on the other) The underlay is not solid sheeting but rather is spaced sheeting. On top of the sheeting is felt paper (with about 6 inch overlap).
> 
> ...


 Hi Fred
Felt was originally used for blowing snow(would fill up attics)
All shakes used to be triple layered & cedar shingles still are.
In this case felt is not required.
Most shakes are now double layered & any double cracks would become a potential leak without felt.
If you are willing to spend the extra money to install 3 layers it makes for a real good installation, but the cost for felt would be fraction of the cost for the extra shakes.
I have not seen any substantial difference in shakes felted or not, layed on strapping or plywood.
The biggest difference is in the quality of the product -for cracking & splitting-blowing holes through spaces at thin points-curling. The mills that are certified actually do make the best material.
CCA pressure treatment is the best thing you can do for the least amount of money. I walk on 500 roofs a year & have yet to see one rot.
Dale Chomechko
DC Roofing Inc


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## webbyonweb (Apr 26, 2009)

Thanks Dale, why the interlayment. Can you not just cover the deck with it and layer the shakes without cutting into strips ? Some people still just using strapping alone with no paper, that's why I ask. 

thanks again for the reply.

Eric


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## Dale Chomechko (Mar 11, 2008)

*Old growth*



johnk said:


> Felt,felt,felt as Ed says.Shakes arent the same as they were 50 yrs ago for one and why not have the extra protection and its code where I come from:no:


 A 400 year old tree 50 years ago is now a 450 year old tree.
Problem is that 50 years ago they wasted half the tree because they thought there was an endless supply
Now they have more grades & more products & bad manufacturers will get the lower grades into the higher end bundles.(worth almost twice as much money)
Don't blame the tree!!!!!!
Dale Chomechko
DC Roofing Inc


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## Ed the Roofer (Jan 27, 2007)

A solid layer of felt paper under the cedar prevents the interior attic air from breathing through the cedar, which keeps allowing them to dry, which prevents them from rotting, curling or cracking so quickly.

Ed


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## Dale Chomechko (Mar 11, 2008)

*4/12 is OK but*



Ed the Roofer said:


> I would be extremely cautious, and make sure I use the felt shake liner, especially in view of the low pitch.
> 
> Shakes on a 4/12 pitch st as long as on a steeper pitch, especially if you are in a snow region, where it will soak up moisture and start to bow, and split. Cedar shingles, since they are applied in a 3-ply coursing, which is standard, will probably last longer, but thet too wil start to bow from retaining moisture prematurely.
> 
> Ed


 I agree with Ed on the 4/12 issue, especially if your using something thicker than a cedar shingle. The roof pitch starts to get more shallow with a heavier shake.
Curling however is only a problem with sawn shakes & shingles, it is never a problem with split shakes. I have seen split shakes many times on plywood & solid shiplap last 20-25 years unteated with no curling.
The reason- because sawn material cuts through the grain, if that grain is curved from coming up to a knot in the tree, the shake curls.
In a split shake this does not happen because the grain is continuous from top to bottom. If a split shake is curved on a roof it is more likely thats the way it was when installed. Keep in mind that this may not hold true in Saskatchewan or the US midwest where shakes have been on the roof for 50+ years


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## Dale Chomechko (Mar 11, 2008)

*Interlayment is a needed*



webbyonweb said:


> Thanks Dale, why the interlayment. Can you not just cover the deck with it and layer the shakes without cutting into strips ? Some people still just using strapping alone with no paper, that's why I ask.
> 
> thanks again for the reply.
> 
> Eric


Hi Eric
The problem is that if a shake developes a crack & it is above or below a space between two shakes water can get underneath. once it gets underneath every nail hole becomes a potential leak.
This scenario does not happen with asphalt shingles because they do not crack(or are not supposed to0
Here is an example of a roof where the installer "cheated"
30 lb fet on the first 3 ft
roofer didn't start interlaying his felt until the top of the 30lb felt (34" up)
all the leaks were at the walls on the eaves
This is a real case example of a complex(39 units) 12 years old that cost $20,000 to shim the first 3 ft only 
This did stop the leaks


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## Ed the Roofer (Jan 27, 2007)

Dale Chomechko said:


> I agree with Ed on the 4/12 issue, especially if your using something thicker than a cedar shingle. The roof pitch starts to get more shallow with a heavier shake.
> Curling however is only a problem with sawn shakes & shingles, it is never a problem with split shakes. I have seen split shakes many times on plywood & solid shiplap last 20-25 years unteated with no curling.
> The reason- because sawn material cuts through the grain, if that grain is curved from coming up to a knot in the tree, the shake curls.
> In a split shake this does not happen because the grain is continuous from top to bottom. If a split shake is curved on a roof it is more likely thats the way it was when installed. Keep in mind that this may not hold true in Saskatchewan or the US midwest where shakes have been on the roof for 50+ years


It is so common here in the Chicago area to see Hand Split Cedar Shakes, typically mediums, but also some Heavies, to bow like a bannana.

These are commonly installed on steeper pitched McMansions in many presigious communities.

They do bow, significantly, which is primarily due to not having a breater area on the underside of the shakes.

Ed


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## judith rausch (Jun 9, 2009)

*Cedar shakes*

How should my roofer have installed the cedar shingles? We had a garden house and covered swing house built and both roofs have rotted decking now from massive leaks through the cedar shingles. 5 Years old. We have to replace the roofs now and do not want to give up the cedar shingles. All roofing bidders we have gotten say cedar shingles always leak and we should not replace the cedar but use regular roofing materials.

Please advise what you think. Walking on 500 roofs and none leaking is impressive. What is the method roofers need to use to acoomplish this?


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## Dale Chomechko (Mar 11, 2008)

Hi Judith
There are different grades of cedar shingles #2s, #3s & #4s all are allowed to have knot holes in them to varying degrees. If your roofer has installed one of these products without felt (which is ok with #1 & #2 shingles) or at the wrong exposure(5 1/2" for a #1 & 4 1/2" for a #2) then your going to have leaks.
#3 & #4 shingles are not even allowed on a residence in my area.
Shingles are a good product but have to be properly installed & you want to buy good product. 
You could put a cheap product on a garden house but would need to rely on an underlayment layered between the shingles to make it watertight
Dale Chomechko 
DC Roofing Inc


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## judith rausch (Jun 9, 2009)

*cedar shingles*

Thanks Dale. Most helpful. Also I read online that stainless steel nails should be used or coated galvanized but not the electroplated. What would be your advice about that? 

BTW felt was not used and the weight of shingles is thin from our view, we have no info from the installer from 5 years ago. He hung up on us.


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## Ed the Roofer (Jan 27, 2007)

I guess those wannabe roofers do not know how to install Cedar correctly.

Do you have any photos to see if they did anything wrong, from the areas that it is leaking the most?

Ed


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## judith rausch (Jun 9, 2009)

*Ed the roofer*

Thanks Ed. Thank you for your reply. I found one cedar shingle literate roofer in my area and he will (at great expense) replace the roof. Correctly. Buyer beware. We have to find out and know the correct way to do things these days just to look after our contractors!!


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## RidgeWalker (Jun 16, 2009)

No one bothered to give the details in the IRC.

The code book says underlayment is required. And there is specific instructiones based on slope and the average daily temprature in January. 

Additionally if where you live the average daily temperature in January is 25 degrees or less, solid sheathing is required on that portion of the roof requiring ice barrier.

Every one has an opinion, some good some not so good. The code books opinion is what really matters, wether the roof gets inspected by a city official or not.

Good luck!


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## Dale Chomechko (Mar 11, 2008)

judith rausch said:


> Thanks Dale. Most helpful. Also I read online that stainless steel nails should be used or coated galvanized but not the electroplated. What would be your advice about that?
> 
> BTW felt was not used and the weight of shingles is thin from our view, we have no info from the installer from 5 years ago. He hung up on us.


You can use stainles nails but they are expensive, hot dipped galvanized nails are prefered.
The electro galvanized nails (staples are EG on ridgecaps) rust apart in the cedar within about 10 years, they are only used as a temporary measure to hold ridgecaps together until the can be properly nailed to the roof. The new pressure treated lumber needs stainles but cedar roofing products do not as they are still using the old CCA pressure treatment
Dale Chomechko
DC Roofing Inc


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## PDB (Oct 20, 2009)

*Felt question*

Hi Dale, 

I am doing a cedar shake roof on 6 inch center strapping with 18 inch shakes -hand split resawn. Where does the felt come down to if looking from the top of the shake?


What would be your felt of choice?

My roof is 4/12 and I am located on the wet coast.

Cheers

Picolo


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## Dale Chomechko (Mar 11, 2008)

Your shakes should be installed at a 7 1/2 inch exposure. Your felt should be the same & actually lay on the tips of the shakes by 3" with the next shake laying over it. 
You will see the felt between the spaces & that will be your next 7 1/2" exposure line.
Dale Chomechko
DC Roofing inc


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## langolier (Oct 8, 2011)

I want to use hand split cedar shakes on spaced sheeting to roof an open porch. I'd rather not use felt just for aesthetic reasons (I don't want to look up and see the felt paper). Am I asking for trouble?


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## Dale Chomechko (Mar 11, 2008)

Cedar shakes were always installed without felt (1970's thing)
The installation process is different 
The shakes need to be triple layered & the offsets between the spaces need to be 3 rows instead of 2 up.
A 24" shake will have a 7 1/2" exposure instead of 10" You will actually require about 33% more material for this installation not the 25% trhat it looks like. The reason is your making up on third of 7 1/2" *not 25% of 10*"
An 18" shake will have a 5 1/2" exposure instead of 7 1/2" requiring 40% more material

I built an open deck & installed 1 x 4 T & G cedar over the entire deck then strapped it with 1 x 4 hemlock & felted it as usuall. In this application it looks good underneath, has felt installed, takes less cedar & still breathes
Dale Chomechko
DC Roofing Inc


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