A friend and I were discussing shingling roofs the other day, and he mentioned that he knew a full time roofer, around Raleigh NC, who does not use tar paper at all. According to the roofer, there was no need for it.
It had been my understanding that the purpose of tar paper was to protect the roof sheathing from rain from blowing back up under the shingles, and from water backing up from ice dams.
My question would be is there a geographical cut off line where ice dams are never a problem (we do get snow around here, occasionally up to a foot), and, if the roof is at a certain pitch, is tar paper really unnecessary.
One other question… what are those lines on tar paper for anyway? I did a search on that and only came up with – “they are primarily useful for confusing the roofer when he begins to lay down shingles”.
Replies
This is a topic that comes up here at Breaktime every few months.
The tarpaper does help as a secondary protection from water, though many argue that it can not possibly perform this function after all the nails that have been put through it. It doesn't do much against serious ice dams, that is what ice/water shield is for.
It does do a good job as a temporary roof until all the shingles are down (it takes a whole lot less time to put the tarpaper down than to shingle the roof, and if a sudden rain pops up while you are shingling....)
I have also seen claims that the tarpaper extends the life of the shingles by a) preventing the wood deck from leaching oils out of the shingles and b) serving as a slip sheet between the decking and the shingles (limiting the impact of sheething expansion/contraction on the shingles.
Mostly, the stuff is so inexpensive that if someone is leaving it off, I would wonder about what else they are leaving out.
The lines: I use the lines to help with the overlap and to help me place the nails.
Rich Beckman
Another day, another tool.
As for the lines, your using them just for nailing down the paper only? Does anyone use them as guides when installing the shingles?
On the few roofs that I have done, we couldn't figure out how to make them work with the shingle rows, so I snaped chalk lines instead.
thanks
st
"Mostly, the stuff is so inexpensive that if someone is leaving it off, I would wonder about what else they are leaving out."Probably one of those three-nails-per-shingle roofers...I had to argue once for 30# felt on a 4/12 pitch roof -- the roofer said ominously it was going to cost more. Like the extra $40 was going to break the bank!
It does do a good job as a temporary roof until all the shingles are down
Hmm, I was taught, gazillions of years ago, that a properly lapped felt installation was the water protection for the roof sheathing. But, given that tar paper does not weather well, we cover it with something that does, i.e., shingles. Much the same as gravel is put on membrane (single or multi-ply) roofs to protect the membrane from exposure.
Ice dams are a rare roofing issue in Texas (excepting the Panhandle). I can't imagine not using felt on a roof. And, I've even seen skip sheathing covered up in 20# felt . . . Occupational hazard of my occupation not being around (sorry Bubba)
Greetings housedktr,
How about telling us where you're from in your profile.
Here's an old thread that covers a lot of info along the lines of an underlayment.
http://forums.taunton.com/tp-breaktime/messages?msg=33637.1
Cheers
thanks,
sounds like if i had a crew to knock out a steep roof in one garanteed sunny day, i could skip the paper.
guess i'll be using tar paper from now own.
st
One purpose of tar paper that most people don't know about (and one of the main reasons shingle manufacturers in the US require it) is fire rating. When roof assemblies are tested for fire rating the shingles (Class A, C) the manufacturers install tar paper. It's just one more layer the fire has to penetrate. If tar paper 'buys' them an extra 5 minutes - that may be all they need to get a class A rating. And with insurance companies (and locally ammended building codes) often requiring class A roofing - the paper ends up being important in their view.
Frankly tar paper isn't much value as a secondary weather resistive barrier on roofs. Once you punch a zillion holes in it you can't expect much benefit. The new roof fabrics like Titanium, RoofWrap 30 and others look interesting though.
MG
Try collecting on the "pro-rated" warrenty from a manufacture that calls for felt paper under thier shingles.
Why pay for a 25, 30, 35 year shingle, only to void the warrenty by trying to save a few $$ on felt paper?
Good point about the fire rating too.
Dave
Of course, most shingle warranties are worthless. Just ask anyone with Certainteed.
Mike
Question: What good is felt paper when it comes to fire? I mean if the fire is up to the roof then the area below where the people live are already scourced.
How often do fires start from the roof down unless its a wood shingle roof?This actually is a good topic even if its an old one.
Be well
andyThe secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
http://CLIFFORDRENOVATIONS.COM
I think the tar paper is a component of the 'burning brand' test where they blow hot charcoal onto the mocked up roof.From inside - out direction there probably isn't much value.I don't know the details of the tests. i only know that fire resistance if one of the primary reasons for tar paper being required by the building codes and MFG.<MG
Michael
This is why I find this topic interesting.The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
http://CLIFFORDRENOVATIONS.COM
Who's Michael?
Who's Michael?>>>dont you recognize me son? I was your dad in another lifetime Michael.
Be well
DadThe secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
http://CLIFFORDRENOVATIONS.COM
I'll have to ask my medium next time I have a session.
I'm availableThe secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
http://CLIFFORDRENOVATIONS.COM
I suspect out in the areas prone to firestorms that roofs is one prime area where fire can enter the house.Of course that depends on all of the other factors such has the type of siding and the amount of vegitation around the house as to what goes first.
As for using felt, I feel it keeps exterior moisture (not water) from the roof deck. As fas as the lines on the felt go, I use them for keeping my rows straight. I am able to follow those lines within a 1/2" across the roof.
"How often do fires start from the roof down"Actually, that's our main worry here in the California mountains. That's why you see people spraying down the roof during a fire. The roof represents most of your surface area, so our local codes require a class A roof. Many people think that if they install a metal roof they're covered, because the metal won't burn. They don't realize, though, that it's a great conductor and therefore must be well-insulated between the metal roof and the decking.
My understanding is that the tar paper is from another era when attics were not insulated and vented properly and ice damning was a problem. With stricter codes these days providing better insulation and ventilation damning is not a problem hence the code requiring the tar paper has been relaxed. Here in the north we do not use tar paper on the roof although years ago it was a requirement.
Here in the north we do not use tar paper on the roof although years ago it was a requirement.
Here in this north we do.
Jeff Buck Construction
Artistry in Carpentry
Pgh, PA
Where is "this north?"
above the mason/dixon line ...
Pittsburgh PA.
Jeff Buck Construction
Artistry in Carpentry
Pgh, PA
I have never been to Pittsburgh, although the wife and I would really like to tour the States someday, I find civil war history interesting, Pittsburgh is far south for me, every thing is relative I suppose, north to me is north of 60, 600 miles south of the arctic circle, which I have crossed on a few occasions.This discussion was about tar paper right.
Don't forget about Lewis and Clark ...
they had their famous boat made right here in River City.
Something about George Washington and some Indians too ....
St Louis got the arch ... but we were the real gateway to the West.
that .. and we send all our water down to help out the mighty Mississippi.
So exactly where's your "North"?
Jeff Buck Construction
Artistry in Carpentry
Pgh, PA
tarpaper is absolurtely necessary in my book. Not only do most manuyfactureers require irt for their waranty, but it protects the sheathing from possible rains while under construction or re-roofing.
In hundreds of re-roofs and repairs I have done, I have almost always seen some signs of minor or major of water having penetrated the shingle layer. In roofs that had tarpaper, there was no damage to the sheathig unless it had been going on for a long time. But when there was no tarpaper, the sheathing had suffered, often enough to require replacement. So in a hummid pr rainy climate, the cost of tarpaper is cheap compared to the cost of resheathing the house in the next generation.
The other thing to consider is when a storm takes just a few shingles off. Many times the tarpaper is left and the water intrusion is minimal.
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Taunton University of Knowledge FHB Campus at Breaktime.
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Something I forgot to mention in my reply last night, is the reason for the lines on the tarpaper. It has nothing to do really with laying shingles. The liones are for rolling ply when applying.
The liner at 9" gives you four ply, the one at 12" gives you three ply, the one at 18" gives you two ply. This is mostly for BUR with hot asphalt, but you are lining up the latest ply with the previous ply and once the tarpaper is down,the lines mean nothing anymore
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
the lines makes sense now. appreciate it...one more of life's great mystery's solved.
>>>....one more of life's great mystery's solved.<<
That's just Piffin............the solver of life's mysteries. <G>
"I will never surrender or retreat. " Col. Wm. B. Travis, The Alamo, Feb. 1835
I think I read this whole thread and never figured out what material you were shingling - everyone seemed to be speaking to materials other than wood. When i hear term shingling I'm thinking wood shingles or shakes and if you don't have issues preventing you from using spaced sheathing and you have a pitch of say 8 / 12 or better don't use paper
on this left coast we often see 18" wide shake felt ( 30 lb paper ) w/ lines on it which one uses to felt a roof at the proper exposure - using the lines for layout and lacing the shakes into the layers never leaving any of the tarpaper/felt exposed
the only thing I have had experience with is asphalt shingles. the only tarpaper I had known about was 3ft, aprox, (don't have any handy to measure right now).
If I ever have to do a shake roof, I look for the 18" wide shake felt you mentioned.
appreciate the info.
piffinystery solver here.
What I still wonder about is why they put the lines on plain paper when perforated is what is commonly used on hot roofs
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Exactly, Go to the head of the class...!
I was wondering how long it would take before someone picked up on it. It took me back, nostaligcally (some 50 years) to some earlier days of 'hot' roofing jobs
If you were laying hot roofs fifty years ago, I'll hand you the cap that says "old crank" that they gave me.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
three things come to mind.
1) Warranty, why would you screw with that.
2) A building inspector once told me that it was in the code that all installations for any construction component was to be done according to manufacturers specifications. I never looked it up myself.
3) A neat little trick that I don't see to often is to not tar paper too far ahead of the shingling and overlap the top of a course of shingles with the next layer of felt. If any water does penetrate the shingle layer you can sometimes get it back out to the shingles before it finds a way in. This is also a good technique to use around roof protrusions like vent pipes and fan boots or skylights.
It's interesting how much the tarpaper has been thinning over the years. I think the article was in FHB - good 30# felt - you're lucky to get stuff that weighs 16# per square.
I replaced a door in a house I helped build back in ~67. Under the old brick mold was the old 15# felt - as thick as today's 30#. You almost have to use 30# these days to hold the stuff on.
How would you decide on how thick of tar paper should be used under shingles? My rule for just about everything has been "more is better". Is there a rule of thumb on where to use 15# vs. 30#, and on how many plys should be used?
I'm in Raleigh, NC.
I'm in Raleigh, NC.
We knew that. We saw it on your profile.
be preparing the way
Edited 11/30/2004 12:05 am ET by rez
I have heard the anticdotal news that 30# can "telegraph" through and show in the finished roof; never had that experience - however that has changed with these new textured shingles. I have retired from shingling unless it is a special case (i.e. our addition or my house).
If it is a tear off, and you plan to use tar paper to keep rain out, or there will be time for it to blow off, better use 30#. It's just hard to keep 15# on (even with staples/string) unless you are covering it as you shingle.
Yep, I understand that. My first reletively steep roof I did was last spring. I learned alot about how "not" to do one on that job. I used 2 layers of #15, and it tore everytime I looked at it.
In the end, it all turned out fine. Next time I would probably try the synthetic paper I've seen for sale now.
My stqandard was 15# on new when it will be shingled almost immediately and 30# on re-roofs where interim threat of rain etc is more likely to cost a claim for water damage.Minimal slope for asphalt shingles is 3/12 to 4/12 depending on brabnd and climate. Doing it with two ply will help marginal situations.I now use RooftopgaurdII which is far superior to any tarpaper but not quite as good as ice and water shield.When we did slate, the standard was a two ply of 30# under them.With shakes, it is two ply of 18# interweaved...
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That explains some of my confusion about something. I kep reading here as guys recommend 30# underlayment for shingles which I always thought of as too heavy and causing wrinkles that could not be forced to lay flat, but you are righht, the new 30 is far less heavy and stiff than what we used thirty some years ago.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
HOuse dk, this is one of those throwback products that actually had a good purpose but is obsolete now, but since "grandaddy" did it, it must still be good.
I've read all the replies and not one of them makes any sense. The only truth is that if you poke a thousand holes in it, it will leak.
If the top shingles fail, then you better have ice and water shield under it...because the nailholes seal themselves.
In the olden days,....they used wood shakes on spaced 1x. The spacing was usually 3/4" and was provided to allow air movement to dry out the wood shakes so they wouldn't mildew and mold. The wood shakes themselves were spaced to allow for expansion, because if you didn't allow it, the all would buckle at the first rain. The spaces allow daylight...and therefore also allowed air movement, as well as some small amounts of rain until the shakes swelled.
The invention of tar paper was probably looked upon as a necessary insulator as well as a water repellant. Even today, when shingling with wood shingles, the paper will back up the spaced joints.
Paper and todays asphalt shingles is useless. I layed a few roofs for myself "bare" and never had any problem.
The firerating idea sounds good, but a little hokey. The protection from leaching is just guess..theres no evidence that I know of. IF that was the issue, would it be okay to seal the ply some other way?
If one layer of paper extends the life of shingles to 25 years...does two layers give it an extra five?
blue
Warning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
The protection from leaching is just guess..theres no evidence that I know of.
I've seen evidence of this doing tear-offs. I've run across several asphalt shingle roofs laid without felt and they were a b!tch to tear off. I'm working in a warmer climate than you, so it might be a regional thing. I've also seen buckling which I believe to be a product of the shingles sticking to the sheathing and the two materials expanding/contracting at different rates. In the spring and fall we sometimes see a hard frost in the morning and high 70's in the afternoon ( hard to figure out how to dress some days).
I invented the "Hit the NBA player with beer" video game.
greencu,
your experience might be a regional weather thing.
up here in Akron
I have torn off HUNDREDS of roofs----the majority had no felt under 'em. I suspect I could count on one hand( and have fingers to spare) the times I had even the slightest problem with even a single shingle sticking to the deck-----and those cases were caused by pine sap.
Never had a problem with a plywood or osb deck/shingles sticking
I have had a problem on small residential flat roofs with the bottom ply of felt baked on to old 1x8's.
Our temp range is sub zero to high 90's ( though not on the same day!)
Stephen
Gee greencu, what region are you from?
greencu invented trouble
rez,
greencu is, I believe, in Kentucky.
( amazing how I knew that by paying attention-----even without checking his profile. LOL)
Stephen
Ya, you certainly are a smart...soul. :o)
Haz is right, I'm just up the road from Sphere ( or down the road if you hold the map upside down).
I did not invent trouble, but I hold an option on the concept.
i've seen the same evidence.. asphalt shingles bonding to the roof deck where no tar pater was used.
also.. the warranty issue is a valid issue
also the 2d line of defense is extremely valid..
i have personal experience with many customers whose roofs leaked..
it was always the ones that had no tar paper under the shingles
and contrarily.. i've been on many roofs that had shingles missing..
that had cracked shingles..
that had tears running from the fascia to the ridge... but they didn't leak because the tar paper protected them
so my experience is the opposite of yours.. i find felt paper under shingles to be extremely useful to my customers.. and now we use RoofTopGuard II.. which comes in 5' x 200' rolls.. and seals around the nails..
so.. we've always used 15# felt on new const.. unless we were doing tear offs on remodels.. then we'd use 30#..
until we started using RTGII about 3 years ago..
Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike, the rtgii sounds like the right stuff to use under shingles.
And...I won't argue with you about the warranty issues. I might argue with the manufacturer though.
If the shingles crack and open up and leak onto the paper...do they cover the shingles? If the shingles open up and leak onto a piece of plywood, do they cover the shingles?
If the paper is designed to break the possible bond between the roof and shingles...wouldn't red rosin paper be better?
If shingles blow off, and there is paper, how do you know that the water hasn't traveled twnety feet south and emptied into the house somewhere else?
These are all rhetorical questions....I really don't want to know....
blueWarning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
Probably rosin paper isn't used because it's too dangerous to the installers.
"The firerating idea sounds good, but a little hokey."That's no doubt true with wood shakes, but with a metal roof, I'm fairly certain that you cannot get a class A rating if you lay the metal on without some sort of insulator and tar paper is one accepted insulator. I'm sure there are other solutions, but I'm also almost certain that a metal roof laid straight on the roof deck would not meet code here.
Blue, are you campaigning for election as ambassador for lowering all construction standards as far as you can possibly lower them and still get away with it?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Nope Piffin...just telling you of some of our successful life's experiences here in Michigan.
I'm not opposed to minimalist building...as long as the product withsatnds the test of time.
More is not sometimes better.
blueWarning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
Back when hot asphalt roofs were in style we used the lines to tell you where to lap the rolls for either a 2 or 3 ply built up roof
As for following the lines you better make sure that you start and remain real straight while papering because if the paper strays your shingles can be straight but crooked paper gives the illusion that they are careful. I snap my roofs out especially 3 tab and to ensure even exposure to the ridge and other critical points for a good looking roof