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Felt paper under cedar shingles

DelawareTim's picture

I'm putting pre-stained cedar shingles on the wall of my front porch. What I think is there now is: sheathing, covered with felt paper, covered with thin (3/8", I think) plywood, which is the (painted) appearance surface.

Should I put up another layer of felt, or just nail the shingles to that painted surface? Is it a bad idea to capture that piece of plywood between two pieces of felt paper?

Note: I can't remove the thin plywood - I need to go on top of it.

Thanks.

(post #108360, reply #1 of 60)

Bump!

A fair question that should have some informed answers coming
along any time.

In the mean time my uninformed guess would be another layer
of TP for good measure, and since it breathes no problem.

(post #108360, reply #2 of 60)

If it's sheltered you definately don't need more felt.



~ Ted W ~


Cheap Tools! - MyToolbox.net
See my work at TedsCarpentry.com


Edited 5/23/2009 7:22 pm by Ted W.

~ Ted W ~

(post #108360, reply #3 of 60)

Hey Tim,


Anytime I've put cedar shingle over a solid substrate, I've used a matrix that's made especially for the application. It's a woven nylon pad, similar to a scotch-brite pad. Not nearly as thick though. It allows air to circulate behind the shingles to get the moisture out. Gotta let them breathe! The stuff is available wherever you buy your shingles.


If the wall is sheltered and stays relatively dry, one more layer of felt should do you fine. The matrix is strictly a suggestion.


Good luck.

(post #108360, reply #4 of 60)

here in the Pacific NW we have sheathing, feltpaper, 1x2 horizontal strips, then nail the shingles on the 1x2s.
Material can breath and you dont perforate the sheathing/felt

(post #108360, reply #5 of 60)

How does water drain down past the 1x2 horizontals?


k

(post #108360, reply #8 of 60)

when you shingle it right there is no waterpenetration.
Just like when you install cedar shingles on a roof with 1x4 strapping

(post #108360, reply #10 of 60)

"when you shingle it right there is no waterpenetration."

You belie your own methodology there. if you "shingle it right, there is no need for the drainage plane you are building.

but of course no siding material is completely water resistant and water does blow into it. Cedar shingles more so than claps.

i've done it every way, like you do, like the guy with the cedaar breather above, over tarpaper, and on solid wood. Varios good reasons for any method.

Someplace like your Pacific Northwet or a wall facing the noreasters on this island of mine needs the drainage plane and breathing space.

 

 


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Oh Well,

We did the best we could...

(post #108360, reply #13 of 60)

In that case, if you feel more comfortable install vertical strips first, then horizontal, cover that with felt and then nail the shingles.
In his case he has felt over his sheathing already plus a painted plywood. Waterpenetration will most likely never occur.
I personally do not like the shingles directly on a flat surface rather have a breathing space behind. this allows them to dry out faster if they get soaked.

(post #108360, reply #14 of 60)

I think everyone agrees a breathing space behind cedar (whether shingles or claps) is a good idea, but that horizontal strapping has always bothered me.  I don't care how careful you are, water will get back there at some point.


k

(post #108360, reply #16 of 60)

Unlikely that it will ever be a large build up of wet water. just enough dew and beads to show up, but not puddle. Nontheless, when I have used horizontal strap and drainage plane, I rip 3/3" strips about 4-5' long and leave slight gaps at butts so water can drain away down if need be.

 

 


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We did the best we could...

(post #108360, reply #15 of 60)

"Waterpenetration will most likely never occur."

Which is why for a small wall over old work I would just nail them on.

Describe a different location and situation and I might choose your way or the homeslicker product.

 

 


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Oh Well,

We did the best we could...

(post #108360, reply #17 of 60)

or you could use this

PreviewAttachmentSize
waterproofing_envelope.htm33.92 KB

(post #108360, reply #18 of 60)

Thanks for all your comments. I'm seeing that furring strips or cedar breather are probably best, but for a well-protected porch wall, probably not necessary.

Regarding tarpaper or not - does the TP serve a function behind the shingles, other than as a water barrier? A couple of possible benefits I see: I assume that the back of the shingles will stick somewhat to the painted plywood, while they'll be a bit more free to expand and contract on top of the tarpaper. Also, does the rough surface of the TP allow a small amount of breathability behind the shingles?

Also, if Piffin is still reading this thread: Are you saying not to use the tarpaper because it's just not necessary in this specific application, or because sandwiching my thin plywood between two layers of TP is a bad idea?

Thanks!

(post #108360, reply #20 of 60)

Both.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
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Oh Well,

We did the best we could...

(post #108360, reply #29 of 60)

if the shingles are installed under a covered porch I would not hesitate to install them directly over the thin plywood.

(post #108360, reply #19 of 60)

I'm not believing my eyes. Suggesting vert and horiz nailing strips, then papering??? One layer of 1x is bad enough, but two? And these nailers are every 6" for sidewall? Are you gonna just 'float' the paper from strip to strip. If so, please don't lean on it.

I'm seeing a checkerboard of nailing strips that are now built up to maybe 1 1/2" - as with any nailing strip, even just one horiz application at 3/4" - what do you suggest at wall penetrations (windows and doors)? Are you gonna use 2x casing/trim materials so as to keep trim proud of butted siding? How do these nailers weatherize at said openings?

I have remodeled here in the PacNW for 30 years. ASTM 15 felt is totally sufficient. The felt is the main line of defense against water penetration. Anything applied over it is just to beautify and protect the main line of defense. Anyone attaching nailers for sidewall shingles around here would be looked at with a wary eye.

For examples sake .... I was asked to re-side a house a little while back. The house and shingle siding dated maybe 40 - 50 years old. They didn't 'need' new siding, they 'wanted' new siding. When we stripped those old shingles, there wasn't a lick of TP or anything between the shingles and the 1x6 shiplap sheeting. Not even at the corners. The sheeting was pristine.

Please, someone, tell me I am misunderstanding this thread!

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #21 of 60)

OK, You are misundedrstanding this thread.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
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Oh Well,

We did the best we could...

(post #108360, reply #22 of 60)

.... and the point I am missing please.

Sig #1: If two people are exactly alike, then one of them isn't necessary.

Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #27 of 60)

Part is that too many here went over board recommending the very best top notch for wet locations when that is not needed for this recovery effort in a protected location.

Then some of the exaggerations got sarcastic, which is I think where you responded to the overkill as tho it were for real.

That's my opine enyhow.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
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Oh Well,

We did the best we could...

(post #108360, reply #30 of 60)

falls in line with some of my thinking.
I was merely suggesting the method our building inspectors want to see on any wall before they issue a permit.
Personally I think a house should be able to breath and not get sealed up with plastic etc. (see the dilemma they created with the Leaky Condo Syndrome).
Turns out now that the shingles are installed on a covered porch wall.
Just nail them on

(post #108360, reply #31 of 60)

http://www.cedarbureau.org/installation/wall_manual/page10.htm

Figure 13 implies that you would be within the Cedar Shake & Shingle Bureau recommendation if you nailed directly onto the plywood.

-t

edited to add: Fig 14. shows what the vertical + horizontal strip approach would look like.


Edited 5/26/2009 4:17 pm by webted

(post #108360, reply #32 of 60)

semar .....

Do you guys actually need an inspector to apply siding? and I thought we were over regulated!

OP: Paper or not, properly installed, the shingles cannot, will not allow water penetration. Pay close attention to inside and outside corners. With 5 1/2" to the weather you will have a triple layer of shingles, 6" to the weather = most of a triple layer.

The other thing to consider is how the shingles will finish to any openings, doors & windows.

Sig #1: If two people are exactly alike, then one of them isn't necessary.

Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #33 of 60)

permits everywhere
first where building permits - ok, then came plumbing permits - ok,
next came electrical, collected on both ends, municipality and the electrical branch, permits to dig ditches, sprinkler permits, fireplace permits, permits to develop a basement, sump pump permits c/w engineer's stamp, engineers on site to supervise rainscreens and building envelopes
Other than your application cost - which is of course extra, you can spend easily 20 - 30k on softcosts

(post #108360, reply #36 of 60)

Semar - Unbelievable .... wow!

Siding, windows, doors, roofs, decks under 30" in elev, .... no ones business but the owner and contractor .... here anyway.

The moment structural, plumbing, electrical or mechanical is altered then we need permits. Even then I think we are over regulated and way over engineered.

Sig #1: If two people are exactly alike, then one of them isn't necessary.

Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #42 of 60)

It is so that city counsellors and other buerocrats can take courses and attend conventions in Las Vegas to study how to bring tourists into the city. They just talked about drastic reductions for services but spend 18k taxpayers money for trips.
They just added a new permit: cutting a tree on your property will cost you. It is for the environment. This is very bad - cutting trees. But if you pay then it is ok

(post #108360, reply #43 of 60)

careful - you might get me going - <smiles> it is all a sham!!, rationalize, justify and make 'em pay.

Sig #1: If two people are exactly alike, then one of them isn't necessary.

Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #34 of 60)

"properly installed, the shingles cannot, will not allow water penetration."

Not true at all to make such an absolute statement. It is well recognized fact that NO siding material keeps ALL the water out. That is the reason we use secondary systems, like the tarpaper, and flashings combined with caulk at window and door opennings.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #108360, reply #35 of 60)

This is absolutely true based on my experience. "properly installed" and attention to detail. I don't really care what the 'recognized fact' is, I know (as in I have personal life experience) my statement is true.

Flashings and caulk are as needed and irrelevant to the thread. Door and window openings are also another matter.

Personally, I would not install sidewall shingles without a minimum of ASTM 15 felt behind it, but I have seen with my own eyes where shingles have been applied direct to sheeting, full on to the weather and 50 years later not an iota of a leak having ever occurred. There is no harder 'fact'.

Sig #1: If two people are exactly alike, then one of them isn't necessary.

Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

Sig #1: If two people are exactly alike, then one of them isn't necessary. Sig #2: Never argue with an idiot. They will drag you to their level and beat you with experience.

(post #108360, reply #37 of 60)

Sorry Mac, but I grew up in your neck of the woods - a Fighting Fisherman, so to speak...

Those 50+ year old shingles you're talking about were usually prime grade A+ old growth, all heart, western red cedar, probably 8+" wide with 1+" thick butts - you know, the cheap stuff! You almost can't buy that grade of material anymore.

-t

(post #108360, reply #38 of 60)

Cedar shingles are made of wood if you notice closely.

Wood is not water proof

vapour pressure and wind driven rain WILL penetrate no matter how much caulk, flashing and paint you use.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...