Hi,
I’m about to start a cedar shingling project. Having removed the old siding on the house I am now faced with an entire house covered with tar paper/felt. Does anyone hae any idea if it’s OK to put Tyvek up right over the felt, or should I remove the tar paper first?
Thanks
David
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Replies
Dave,
Remove the felt first.
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
New tarpaper, skip the tyvek.
Ditto on the new felt. Tyvek has not withstood the test of time like felt has. I have even uncovered 4-5 yr. old Tyvek that was disintegrating. Dupont doesn't like the idea that more and more builders are now going back to tried and true felt.
Ken Hill
Use red rosin paper rather than felt or tyvek.
david
walk good
Dave, seems to me that you're in Montana or Wyoming or some such dry and cold place. From what I've read, rosin paper is a decent choice in such climes. But I disagree about using it anyplace where it rains a lot, say east of the Mississippi or in the north west. In those places, you need housewrap or felt, something that can drain bulk water.Andy Engel, Forum moderator
Andy,
I began my carpentry and house building in New England, most the coast of Maine and a bit in the hills of ol' Vermont. The old time carpenters I learned from used rosin paper for building paper, for under flooring paper and even as wind paper under cedar shingles. A few taught me to run 15# felt along the starter strip of the house or along the rake wall of a dormer, anyplace where snow might accumulate. Some didn't bother. Some doubled up the course exposure on the bottom 4 or 5 courses of shingles on the house walls for the same reason.
On old houses I have remodeled or rennovated in New England, Minnesota and Oregon I have found red rosin paper for the same purpose. It is a good choice with a longer history of use than felt. Both are saturated papers, red rosin uses rosin gum from pine trees, satuated felt uses petroleum products.
you need housewrap or felt, something that can drain bulk water.
Andy, I think better of you than to accept this statement from you. Siding is for protecting the house from the weather elements not your building paper. If you have bulk water then you have either a failure in your install or improper install to begin with.
One reason I use felt is it's absorbtive qualitys. There is sometimes wind driven moisture or saturation moisture like a good soaking fog. Even the best of siding jobs will pass some through. Red rosin paper absorbs this moisture and disperses it alng the paper much more readily than ythe wood can absorb it alowing better and quicker drying. Felt paper does the same thing, but at a much slower rate . The old practice of running felt strips under siding/casing joints may actually be creating an environment more prone to rot, by concentrating more moisture and retarding drying time. I have no proof, just some logical thinking.
Housewrap is even worse as it absorbs no liquid, forcing the water to be absorbed by the wood instead. We hear it often said the necessity of housewrap as a water barrier. Again that is the performance required of the siding. The proper siding for the conditions, properly installed. Perhaps husewrap is neccessary on houses using colourlok or masonite or vinyl siding where the siding by design allows water to penetrate the siding.
just some thoughts, Andy
david
While I got your attention... this is the third try at replying to you. The first two, resulted in a type 10 error, complete with a little bomb symbol, which completely froze my computer. This happens enough on this site, usually during replys to be annoying. Not a computer person so I do not know the wherefores and the whys. thanks
walk good
Dave,
You may not realize it yet but you might have just started one of the longest threads on the new improved Breaktime forums. This seems to be one of three or four topics about which there is no agreement or concensus amoung professionals so we tend to devolve into unprofessional behaviour over the issue.
Sure, go ahead if you want but it would be easier shingling if you remove the felt first but it doesn't make that much difference. New tarpaper would be OK tooo. Whatever shivers your timbers.
I use Typar ( the gray stuff) because it seems to hold up better if it doesn't get covered right away and it's a little more tolerable to look at. The white stuff is blinding to work against on a sunny day. The Pink stuff is junk. ( All of these are merely my own well thought out opinions).
Now having said that, when shingling I use tarpaper and the scientific reason (that I've concocted) is that shingles are just easier for me to run on tarpaper...it feels right...
I, too, have peeled siding and roofing off structures much older than me and found the tarpaper as good as new.Measure it with a micrometer, mark it with a piece of chalk and cut it with an axe.
The old felt is better than new typar, tyvek, barricade, kraft paper, rosin paper or any number of other inferior materials in this application. Of course new felt is what i would want on my house.
Tyvek is for envelopes and disposable jumpsuits.
joe d
The 100-year old tar paper on my house looked like new when I popped a few shingles for repair. 'Nuff said....that's not a mistake, it's rustic
Joe- Don't forget that you can make some dandy kites out of Tyvek,too!
Ken Hill
My building dept requires the use of tyvec, rather than argue, I just put it up and then covered it with felt. they get what they want, I get what I want. Win, win. (and if you think that cost is a factor then you haven't been reading any of my posts).
Correct me if I'm wrong, but does'nt cedar cause Tyvek to deteriorate? Our current practice is that with cedar or cypress siding we install tar paper. Pine novelty siding gets typar.TCW Specialists in Custom Remodeling.
joe d
Felt used as a siding paper works well. So does red rosin. Each paper has it's advantages especially when used with specific siding.
For cedar shingles and wood siding in general, I prefer red rosin as it's wicking action contributes to greater dispurstion of moisture which allows for quicker evaporation and dryer siding and sheathing.
Felt works better behind masonry and cement board products as it is better at shedding liquid water, though continued exposure will saturate the felt. It takes much longer to dry felt out but is of less concern with masonry walls.
Tyvek, etc are unneccessary even for envelopes and jumpsuits.
walk good
Dave - Leave the old, cover w/new 15-lb. building paper, skip the Tyvek.
T. Jeffery Clarke
Edited 4/22/2002 2:10:55 PM ET by Jeff Clarke
Oh gosh...here we go again. The idea that cedar causes rot when exposed to Tyvek is not new, but certainly not proven at this point. Is it cause for concern? Perhaps...and should definitely be investigated. However, the true "rot and cedar" problems I've actually seen had a lot more underlying concerns and shoddy construction to go with it. But like anything else, I just don't think there's enough non-anecdotal evidence to presume that one product is causing all these failures...particularly when they just aren't that prevelant given the number of housewrap installations in this country. If it "caused" rot...wouldn't we be seeing a whole lot more problems?
The second thing I worry about is the whole "this 100 year old felt looks great" routine; I'm sure it does. The problem is that houses and the entire building envelope from 100 years ago ain't nothing like we're building houses today. Houses today have all sorts of different materials, different customer lifestyles, and different climatic variations inside. Who's really to say that the old time felt, which worked great before, is going to still be the wonder underlayment in another 25 years on modern homes?
We just returned form a 10-year old cedar home (SIP), that the customers are having paint problems. They too had heard of all the horror stories of cedar over housewrap, so we pulled off a bunch of boards all over it. The underlying Typar is perfect, as is the OSB underneath. And no backpriming...but simply a really crappy paint job. So why isn't this rotting out? But to answer your question, I'd never mix and match any two underlayment products of that sort...too much chance of vapor being trapped between them...and a waste of money.
Edited 4/22/2002 4:30:16 PM ET by JASON_MI
How many 'horror stories' did you hear about felt during the first 20 years of its use? T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Jeff,
None of us are that old to remember.
either product will do as long as either is installed properly. Tyvek is just more forgiving and faster. Which is better?
Felt
Gabe
Jason,
My understanding is that Tyvek and other similar housewraps breakdown and loose their manufacturer's stated effectiveness when covered by siding such as cedar or cement board. Have not heard any problems with rot developing as a result of using the combination.
You are correct about material difference in construction, and much to our lament. Much of the argument for using housewrap is as a secondary barrier for the elements. This may be necessary because 1. we no longer know or even more criminal, care about proper technique in siding, 2. we use new siding material that is inferior in design and material from time-tested material and 3. we combine 1 and 2 which is a prescription for problems.
davidwalk good
I don't want to give you guys the wrong impression...I'm not like a tyvek advocate or anything like that...I just want to make sure that we're identifying the proper causes and using good sense and good science to build the best houses possible. I don't pretend to be as knowledgable or smart (building science wise), as most of you, but let's face it, when you and I pull siding or trim off a 100-year old home, and there's rot, there's an underlying concern...how did water get in. Was it flashing, was it detail, was it worn out, poorly put on siding. Did felt and cedar stand up better over the past 100 years because felt and old cedar are better? Or is the whole building envelope SO much differently constructed (e.g., lack of insulation, ability to dry, etc.) than today's that the combination allowed thorough and easy drying. So...with modern, and in many cases inferior materials, tighter houses, and using felt...is that going to last as long? That's my first question; and an answer to Jeff's question about felt horror stories; we aren't building like we used to so we don't know how it will react in the long run. Chances are, it'll be fine, just as it always has.
As for Tyvek, when I hear about rot, everyone assumes it's the tyvek. But is it the flashing, siding, other materials, something we're doing differently with the building envelope? Or IS it the tyvek? I just don't think there's enough information there to call it "good science" that tyvek and cedar, or other building materials don't mix. I read every stinking piece that was brought up by Fisette, JLC, the JCL CD, etc. that you guys and Andy Engel brought up on one of the old threads on this, and no one had a definitive piece of evidence about it. And why is it Tyvek? How come I don't hear about Typar, AmWrap, etc...is it Tyvek, or all building wraps? Finally, if there truly is a problem with this product, why are there really so few known failures? I mean, this stuff is installed on hundreds of thousands of homes and businesses, but we really aren't hearing about widespread failures. Any clues on that one?
Like I said, I don't want to boost this poor man's thread; but I'm very curious about this whole housewrap (or Tyvek) issue, and have been for some time, probably because I see more "I heard of " issues than actual issues, and I don't see real research to back it up.
I have never singled out Tyvek. I've always used the term housewrap. From the JLC article, Tyvek is the best performing plastic housewrap. It's just that it's become the Coke or the Xerox of housewraps.
For me, the choice is quite simple. I think that the air-infiltration qualities of housewraps are over-rated given the other components that go into houses. Felt has a track record and it's cheap. What more do you want?Andy Engel, Forum moderator
FWIW - click here for the FAQ's regarding Tyvek.T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Thanks for the link, Jeff. I particularly like #27 about Cedar siding...looks like someone's trying to cover their you-know-what, just in case!
Sorry Andy, didn't mean to imply you SAID anything, merely that you helped out by pointing out all the other places to look for information. And my only question on felt was whether it would continue to hold up to it's long track record, given the changing methods and materials used in today's construction. Just trying to get a grip on the "whys" of these two materials in the modern construction world, that's all...
Jason, you're right to point out that felt has changed. We did a What's the Difference piece a few years back on that. If you look carefully, you'll see that it's no longer 15 lb. felt, but rather #15 felt. Used to be that there was 15 lbs. of asphalt per square. No more. To get that now, you have to buy #30 felt.
I agree that there's a lot of misunderstanding and half-truths out there. One thing that Joe Lstiburek will tell you if asked is that he has Tyvek on his house. The stuff's not all bad, and used correctly, it can work fine. As can felt. I think that proper flashing and shingle-type installation is far more important that whether you use felt or housewrap. I chose felt over housewrap largely because of my Scottish heritage <G>.Andy Engel, Forum moderator
Andy,
You are certainly right about rosin paper in the NE part of the country. I can remember a couple of times removing siding for replacement and finding that the old rosin paper had actually disolved and no longer existed in some spots where it was likely that more water intrusion had occured.
One of my biggest determining factors in which product to use is how long it is likely to be exposed to the elements and under what conditions. Felt will blow off in the wind on a beach house pretty quickly so it is better for jobs where we are covering it back up right away. Sometimes there are reasons that the wrap is left on for a long time, (eg. while you work inside during the winter) so the housewraps are better there. I know that the literature calls for having it covered before thirty days are up but ...
One of our local jokes is this, "What is the most popular siding material used in the state of Maine?"
Answer....
Tyvek
Excellence is its own reward!
Of course, if you're choosing felt or housewrap or rosin paper based on the facts of rain- well, geez, it really is ONLY a second line of defense. If you've got water running past the siding/flashing/caulking, I'm tellin' ya right now that you've got bigger problems than whether you used Tyvek or felt!
Ken Hill
"If you've got water running past the siding/flashing/caulking, I'm tellin' ya right now that you've got bigger problems than whether
you used Tyvek or felt! "
And I'm telling you right now that you are only fooling yourself if you think that there is an envelope page that exists that can keep all airborne water out of the walls - or will for a hundred years.
In my example I was refering to homes that were 70 - 100 years old with the original cedar shingles on.
Excellence is its own reward!
Piffin-
As usual from you, a point very well taken, and one which affords me the opportunity to be critical of my own thinking and learn something. Thanks, bud.
Perhaps you may have misconstrued my comments. I did not say that the envelope alone should prevent any and all water penetration. I DID say that if water is RUNNING behind the envelope, you have PROBLEMS. At least that's what I meant to say.
I do agree as to the integral importance of the building wrap, whatever product it may be. I'm still inclined to favor felt, mostly for the factors of breathability and H20 dispersal as David points out.
Thanks for your comments.
Ken Hill
Edited 4/26/2002 2:46:01 PM ET by Ken Hill
It was just the brief way it was worded. No offense taken amoung gentlemen.Excellence is its own reward!
Piffin-
No offense taken whatsoever.
Glad that you mentioned AIRBORNE water, 'cause rain is not the only source. H20 (vapor) from within AND without. TRAPPED water seems to be the bugaboo. Perhaps the tighter the building envelope, the harder it is to disperse the trapped water. Wonder if anyone has used the plastic fiber mat (seen it spec'd. for shingle and shake roofs) behind siding?
More I think about it, the more it seems that the cedar shingle siding is the very best as far as breathability AND longevity are concerned.
Cheers, Ken Hill
I think I read all the posts on this thread and I didn't see any mention of Grade D tar paper. This is the stuff to use. I comes in a double layer roll and is more water-vapor permeable than traditional tar paper. It also wrinkles less. I believe the new codes require Grade D under stucco. We use it under all our siding, never housewraps under any wood siding.
Steve
A few more comments on the Tyvek thing. First, I'm not a Tyvek rep or salesman, but I think some reasons for using Tyvek [ my preference of housewraps] haven't been mentioned yet. We typically frame our own houses with exterior walls built laying flat on the floor decks. We install 9' Tyvek before the walls are stood up, leaving extra at all edges folded back to be lapped over next adjoining sheet. Once walls are in place and all fill in sheathing is applied, joints are properly lapped and taped. Our exterior sheathing is now pretty well protected from the elements until receiving the siding and trim. Felt paper just wont stay on a building with any major wind in our area without a lot of damage. That means wasted felt and time repairing it. As to cedar and Tyvek being incompatible, I don't believe it. I've built hundreds of custom homes in the past 27+ years and have used Tyvek since it first came out in our area. It does perform better in recent years in holding up to winds, after a change in it's manufacture design. I've used western red cedar clapboard, backprimed and stained on most of those homes and haven't had a problem. We've gone back and added windows, room additions, etc to some of those homes and removed siding with no deterioration noticable to the housewrap or siding. I do think that any underlayment can cause problems or fail if not applied in a proper manner, or not sided over with proper attention to detail. We use caulks that are recommended for the siding such as polyurethanes, etc. not the $1.99 specials at HD, and try to flash all areas as best as possible. Felt may work fine for many people but for us I really think that when the speed we can apply 9' Tyvek to walls laying flat is offset against the higher material cost of Tyvek, We are still money ahead.
Bish
Ya'll mention water penetration a lot, but no one mentions the use of rain screens.
Most older homes that still have intact siding, and no rot behind the siding have rain screens. Even with the newer siding materials, and the newer interior products being used in homes today, rain screens WILL prevent an awful lot of the problems associated with trapped moisture.
Just a thought...James DuHamel
J & M Home Maintenance Service
"Southeast Texas"
I have to agree with Piffin - All siding leaks eventually. I think of the housewrap or felt as the first line of defence, with one of the siding's chief jobs being to protect that drainage plane. There is no downside to thinking that way. Also, backpriming cedar is said to go a long way in preventing its tannins from leaching out and degrading the housewrap or felt.Andy Engel, Forum moderator
James, which material do you prefer for use here on the Gulf Coast, Felt or Tyvek and why?
Thanks
As to cedar and Tyvek being incompatible, I don't believe it.
It's not housewrap and cedar, it's UNPRIMED cedar. Even DuPont believes that there is an issue - they specifically address it as an issue in their FAQ's and instructions. It's not tannins, it is surfactants, or soap-like extracts that migrate from unprimed cedar into the wrap. The polyolefin is dependent upon surface tension to resist liquid water penetration, and the surfactant action decreases that. You can duplicate this by making two 'dishes' out of tyvek stapled to frame and filling one dish with water and one with a solution 'contaminated' with 3-4 drops of dishwashing liquid. While the clean water will be retained, the contaminated water will pass through the housewrap.T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Not a big fan of housewraps either, but I have a situation where the initial siding will be rough tex. T-1-11, fir plywood. This, of course, will need a barrier behind it on the studs. As the owners budget will allow, the T-1-11 will be sided over with cedar shingles which will also need a barrier installed. So in your opinions, what is the best solution?
Kim Sheehan
Meridian Home Builders
Washington State
Kim
Writing here from your neck of the woods, namely Vancouver, BC. I think you should be looking at rain wall systems. As I look around this city I see, and have seen, almost every condo-type building that has been built in the last 15 years get wrapped in the scaffold and netting that says "I leak and I'm costing every owner here about 25,000 bucks"
We've had an expensive and extensive inquiry into why this disaster has happened. No smoking guns. A few smoking tire strips on the road as developers leave their numbered companies behind along with the joke of a "Home Owners Insurance Policy" that came with their homes. This policy was funded by the developers, unregulated by anyone except them, of course. It was funded to about 5%. So the first few victims got some repairs done.
Down to the Nitty-gritty:
I watched a buddy of mine finish off his day on a huge project. He was subbing, being paid by the square foot. My friend is a talented and creative person. He was a little down on his luck and ending up working for this siding co. They were paying something like $35 a square, about the same that we got 20 years ago when we got to know each other. And we weren't working on three story condos with ridiculous details, decks, dormers and curved windows.
If you think there are a lot of creative talented people that are going to find methods of speeding their work up and eventually say" well f--- them if they don't want to pay" Then you don't know human nature.
Now that I've got that rant off my chest, let me tell you this:
A house on an Island near Vancouver;
Diagonal 1X6 channel siding.
Someone had nailed a 2X4 to the siding and hung short rafters off it to provide a shed roof for firewood. I think the sheathing was polyethylene. No overhang above it.
This is a forested area, cedar, fir, the former drops its leaves like a deciduous tree. Anyway lots of rot in the siding. Sheathing, (1/2" ply not too bad.
What's interesting, in terms of this thread, is that the tar paper had disintegrated to nothing exactly along the lines of the siding. Along the top edge, as I recall. Looked like what we used to call 15#. Now up here it's rated in time i.e. 20 minutes to permeate.
Good luck
Alan Jones
One of our local jokes is this, "What is the most popular siding material used in the state of Maine?"
Piffin, Shows you how times have changed. When I lived there the answer was felt and batten.
With rosin underneath.
davidwalk good
What about felt paper holding moisture against the back of the siding, pusing off paint -- an argument made against felt paper.
How is that different than housewrap?
Backprime the T1-11. It's fir, which is tannin rich. Tannin, as I understand Joe L.'s explanation, behaves similarly to surfactants. BTW, if surfactants are the problem, don't pressure wash the house with a detergent solution <G>.Andy Engel, Forum moderator
reply to MERIDIAN02:
you can still make your walls with felt and T1-11, build up the walls laying on the deck and stand up when complete, we just built a place like that (owner spec: "no housewrap"). It was slightly more effort to do with felt but came out just fine. Special care should be taken to make good flashing around the penetrations since the T1-11 is being used as sheathing and siding until the shingles are added.
reply to BISHOPBLDR:
all the statements you make are good ones, for workability. But, I think that if the customer is aware of all the facts, and is interested in paying, what I think, is a small mark-up to use felt then I say 'sure'.
don't pressure wash the house with a detergent solution
How about don't pressure-wash WOOD!
Seriously, Andy, given how easy it is to force water behind claps and shingles with a power-washer, I wonder if pressure-washing would contribute to housewrap failure. T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Jeff, it's just a thought experiment. I've found however, that if my feeble mind can conceive of a building problem, nature can usually execute it. But never mind wood, how about a siding such as vinyl, which inherently leaks?Andy Engel, Forum moderator
VINYL siding? What next? Suggesting that architects sell stock houseplans? Sheesh!T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Dave,
Did the opposite on my home. Housewrap had been exposed too long- too busy.
Stuff started to fall apart. ( we're talking 2yrs plus ) Pulled off what was left.
Replaced with felt . then back stained cedar shingles and clapboards.
Adding new windows in 1st. part of home now. Removed some cedar, over felt.
No apparent failure of either, after 10 years. For my money it is felt.
Use housewrap for many customers though-their money.
Good luck!
Brudoggie