Hi Everyone!
I have a two fold question. My home has aluminum siding. After an addition I am considering replacing it all with a cement board siding with the thought that the house wrap might be updated for better insulation and to give it an updated appearance. When speaking to someone who is considering building new, she stated that the builder told her that they would not put any housewrap on her home at all – just caulk the sheathing and put the vinyl siding over it. I was a little shocked at this and wonder if having no wrap at all is wise.
Or is it because the sidings are different and that calls for a different housewrap or no wrap at all? I have also heard that Tyvek does not prevent moisture build up and can cause mold and the sheathing to rot.
I guess I am trying to get the answer to both questions. What do I do on my own home and is it wise that a builder is not installing any wrap on my friend’s home. We live in Northeast Ohio in case this is a regional practice.
Thank you all for any info you can supply.
Replies
Your friend should hire a different builder unless she wants a house with major water problems.
That is what I was thnking. Should there not be either the Tyvek or 30# felt paper or tar paper or something? What kind of housewrap do you recommend for a vinyl sided or cement board sided house?
You hear all sorts of stories.
Housewrap is primarily an air infiltration barrier. It's also pushed in some circles as a secondary rain shield, but the need for that depends on the weather conditions and type of siding, and there are better systems where a secondary rain shield is really needed. Fiber-cement siding in Ohio should not generally need a substantial secondary rain barrier.
The two major brands of housewrap are Tyvek and Typar. It's probably a religious decision as to which is better -- they both have their good and bad points. Neither will "trap moisture" or cause rot, but they don't make up for poor building practices, poor caulking, lack of interior vapor barrier, etc.
In your part of the country I'd say housewrap should be used, unless some other well-specified "system" of infiltration control is being used instead (and simply caulking the seams of sheathing isn't it). The wrap should be carefully taped around doors/windows and at seams for optimal performance.
is it possible the siding that the builder is using has that insulation that is already glued on the back? Maybe there's no need for a housewrap then? I dont know for sure though...........
That wouldn't eliminate the need for a housewrap. "Permanent" siding is inherently air-leaky, and there needs to be some other air infiltration barrier.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
In the builders defense, I think he plans to use the caulk and sheathing as air barrier - which would actually work quite well.Justin Fink - FHB Editorial
the idea of depending on caulk that can not be replaced bothers me
Oh absolutely. I'm not saying the guys is smart, I'm just assuming that's his line of thought. Besides, weather resistant barriers are required by the building code - no two ways about it.Justin Fink - FHB Editorial
"The wrap should be carefully taped around doors/windows and at seams for optimal performance."
You should see my post/s on the thread about leaking windows under the "General Discussion" section, I believe.
Edited 5/12/2006 12:30 pm ET by experienced
"Neither will "trap moisture" or cause rot, but they don't make up for poor building practices, poor caulking, lack of interior vapor barrier, etc."
You have to be careful with the new wraps as they are 2 to 4-5 times more permeable than most tarpapers. If water/condensation gets trapped behind southeast to southwest facing siding (especially absorbent wood/wood based), the sun's heat will turn this to vapour and it will move back through (reverse diffusion) into the sheathing/studding and cause rot. First saw this here in 1994.
Rainscreen is not a bad idea when using tight caulked siding like Hardiboard, wood clapboard. Vinyl and metal clapboard is so loose to air movement and drying that no screen is needed. FYI, brick veneer has always had a rainscreen.
Some tests suggest that felt paper performs better as a weather barrier than the plastic products.
For the cost, I cannot see why anyone would skip the wrap.
Ideally, you would also have a rainscreen design to support a drainage plane.
So the consensus is there is a definite need for a house wrap no matter what siding is used?
The house wrap is to block air? A vapor barrier is still needed? And possibly a water shield? The vapor barrier is achieved by the insulation on the inside?
Tyvek or felt paper are both acceptable?
And the builder who does not apply either is short changing by friend?
In conventional construction you have, from inside-out, drywall, insulation, exterior sheathing, and siding. In some fairly old homes you don't even have the sheathing.There are several problems that can occur with this wall structure (assuming here an environment cold enough for the heating season to last longer than the AC season) ---- Water leakage from the outside around penetrations (windows, doors, etc)-- Water leakage from the outside through joints in the siding due to wind-driven rain-- Moisture migration through the siding material itself-- Air inflitration through the siding, sheathing, and wallboard, and into the house-- Air infliltration around outside penetrations-- Moisture from the inside, migrating into the insulation in cold weather and condensing inside the wallsIn general, water leakage due to penetrations should be completely handled by proper flashing and caulking. But since failures here are common, it's often wise to have a "backup".Moisture migration inward through the siding material is generally only a problem with punky hardboard siding or wood that's poorly maintained. Obviously, metal and vinyl siding have zero migration of this form. Fiber-cement siding may have some, but very little if properly painted.Wind-blown rain through the siding is an issue. Clearly it can happen with vinyl/steel siding, due to the loose joints and seams, though how much it happens is probably highly variable depending on installation, house position and design, and the weather. Wind-blown rain through wood or fiber-cement siding is signficiantly less likely, though it depends to a degree on whether the siding is blind nailed or not, and other installation details. Wind-blown rain through face-nailed wood, hardboard, or fiber-cement siding should be quite rare, but there are a number of reasons (not all asthetic) why face-nailing is not always wise. So the real questionmark is blind-nailed siding -- does it have a significant wind-blown rain problem or not?Air infilatration is the next issue. Clearly, vinyl or steel siding provides very little resistance to air infiltration, while face-nailed "punky" hardboard is oddly near the best (the "punky" hardboard swells and seals any cracks between planks). As with rain-driven moisture, face-nailing vs blind-nailing can make a difference with wood/fiber-cement, but both approaches are going to be head-and-shoulders better than vinyl/steel.The sheathing also contributes to air infiltration control. Most sheet products used for sheating in the past 30-40 years are pretty good from an air infiltration standpoint, but the problem is at the joints. Even when tightly stapled/nailed at the joints there is a potential for substantial infiltration.One would think that the drywall also contributes to infiltration control, but not really. Once air infiltrates into the wall it can easily exit through electrical outlets, around doors and windows, and at the bottom edge of the drywall.Air infiltration around penetrations is an issue of getting a tight seal between the door/window and whatever infiltration barrier you have, plus preventing infiltration through the door/window structure itself. You can have situations, eg, where air gets in through a joint in the windowframe and then gets into the walls.Finally (if I'm counting correctly), you have the problem of moisture migration from the inside-out. This gets kind of complicated to explain, but if you have a temperature inside of 70F and a temperature outside of 20F, then you can kind of figure that about halfway through the insulation in your walls the temperature will be 45F -- the temperature falls fairly evenly going from inside to outside.Now if the air inside is 40% relative humidity (a comfortable level) then is has a "dew point" of something like 45F. So if you take some of that inside air and cool it down to 45F, moisture (dew) will condense out. So, if moisture can easily get inside the walls from the inside, and can't easily exit through the outside wall, moisture will tend to condense about halfway through the walls, and over time this moisture can build up enough to rot the framing. Further, if it's sufficiently cold outside the moisture will actually freeze inside the insulation, making it a pretty good conductor of heat (and cold) and making the situation even worse.The trick, then is to keep the moisture in the walls at a low level, by preventing it from entering the walls from the inside, and by allowing it to leave through the outside. Regular drywall does a lousy job of blocking moisture migration (though with the proper paint it is much improved). The paper facing on fiberglass insulation (usually with a thin layer of plastic laminated into it) is better, but needs to be tighly sealed at the seams to be effective. A plastic vapor barrier stretched across the whole interior wall (under the drywall) and taped at the seams is much better.Note that housewrap is explicitly designed to NOT be a vapor barrier. It allows moisture to migrate through fairly readily, even though liquid moisture will roll off to a large degree (kind of like "breatheable" raincoats). Ironically, though, housewrap can still contribute to the interior moisture migration problem by reducing air infiltration and hence reducing the mixing of dry outside air with the moist inside air in the wall cavities. (But this shouldn't be a problem with a proper interior vapor barrier in place.)Of course, you might wonder if having an interior vapor barrier isn't sufficient for infiltration control -- do you really need a housewrap too? Well, if you have only the interior vapor barrier, then you effectively have wind blowing through your insulation from the outside, reducing its effectiveness. This is a problem especially with fiberglass insulation where such infiltration can cut insulation effectiveness in half or worse. (Plus there are a few other reasons why the inside vapor barrier is not an ideal infiltration barrier.)I think this covers everything but the issue of a rain shield for backup coverage around windows and for wind-blown rain through relatively "loose" siding. This seems to be something of a religious issue, so I'm not going to delve into it here, other that to note that in my (admittedly limited) experience I've not seen the need for it in ordinary residential construction.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
"Regular drywall does a lousy job of blocking moisture migration (though with the proper paint it is much improved)."
Joe Lstiburek developed a tight drywall system called the "airtight drywall approach" or ADA in lieu of a sealed air/vapour barrier. This system when properly installed provided a more durable airseal in preliminary testing 5-6 years after installatiion from the mid to late 90's. The system only seemed to catch on for a while in British Columbia.
About 98-99% of moisture movement into attics/walls from the interior is by air exflitration; any work on the vapour barrier function by special paint, etc is a waste of time. A researcher here says that the primer and top coat is all that is needed except in extreme situations such as pools and other areas with constantly very high RH's.
"in my (admittedly limited) experience I've not seen the need for it in ordinary residential construction."
Every brick veneer wall put up has a rainscreen behind it!!! The rot that I've seen does not get severe enough to show or indicate a problem until 6-10 years after construction. So I advocate do it up front.
The last house I consulted on (2 months ago) with severe rot from rain leakage actually had brick veneer with a poorly designed flashing system at abutting roofs and all windows and no weep holes in the bottom course of brick.It was 9 years old before the first water made it through to the interior and the....... a $35,000 repair bill. The problem area was not big- whole front wall about 24' wide by 2 stories- but required full removal/replacement of the front facade.
Edited 5/13/2006 11:23 am ET by experienced
Thank you so much for all the info. Totally answered my questions and then some. I will certainly pass this on.
I don't see how some building codes would not require some sort of house wrap in this region or why a builder would not include it as a normal building procedure. Did I just answer my own question?
There is a lot of confusing info on house wraps and it's difficult to find definitive sources. By and large, properly installed house wrap will improve energy conservation. In addition to house wrap, a drainage plane is now being used under porous siding. Future research and experience may change the current practices. Here are a couple of sites that explain the concept fairly well. To date, I haven't used either product and I'm not endorsing them. Their sites do have some easy to read info. The second site is for a new product that acts as a house wrap and a drainage plane. http://www.bma-sales.com/Installation.htmhttp://pactivpartners.pactiv.com/productcatalog/Rooms/DisplayPages/LayoutInitial?Product=com.webridge.entity.Entity%5BOID%5BAC252BDD2F2AD711A4860002A5FBF6DF%5D%5D&ProductCategory=com.webridge.entity.Entity%5BOID%5B33A485043409D711A4830002A5FBF6DF%5D%5D&Container=com.webridge.entity.Entity%5BOID%5B0D5164C14109D711A4830002A5FBF6DF%5D%5D
Beat it to fit / Paint it to match
That Rain Drop looks pretty similar to the Tyvek Drainwrap I had mentioned. Do you know of any differences?
Dupont thinks the drainwrap is superior. They have been the leader in the industry. The green guard is quilted. I don't know about the Tyvek. One of the problems in researching these products is that they play games with ASTM standards. One company will use one testing method while another uses a different standard.Beat it to fit / Paint it to match
Check out the FHB article a couple of issues back on house wraps.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
DanH - Very good summary of the happenings on all sides and in the middle of an exterior wall! However, I beg to differ with one small point, or better put, expand on that point. You stated that you should install a vapor barrier on the interior face of an exterior wall to stop vapor laden interior air from penetrating the wall. My position - this depends.
Here in the South where our climate is classified as hot and humid, you should NEVER put a vapor barrier on the face of an interior wall. Because of different climatic factors, we need for the interior vapor to be able to get to the outside. Otherwise it would stop at the interior vapor barrier and collect at the back side of the gypsum board, creating a great place for mold to grow. Conversely, if the high humidity penetrates our exterior siding, flashing, house wrap, sheathing and insulation, it will stop at the interior vapor barrier and depending on the environmental factors, the cooler interior temperatures could reach a dew point at the back side of the vapor barrier. Not good.
For example, if anyone has ever peeled back a layer of vinyl wall covering and found black mold, this is exactly what has happened. Maybe this only happens in hot and humid climates. The vinyl wall covering has acted like the vapor barrier, trapping the incoming moisture at the gypsum board/vinly wall covering junction. Obviously, the example in this thread was set up for a different set of climate factors and I assume works well for that climate. My point is that it may not work for other climates. DanH, from your thoroughness, I am sure you are aware of this, but did not mention it, or maybe I missed it!
In any case, there is an excellent web site that has a lot of very good information concerning the construction of foundations, floors, walls, ceilings and roofs for all of the major climate types found in the USA and Canada (If I recall correctly). Their research has shown that the proper construction of the typical wall section may vary somewhat to accommodate the effects of the different major climate types. The name of the company is Building Science Corporation in Boston and their website is http://www.buildingscience.com. The principal contributor is Mr. Joseph Lstiburek, Ph.D., P.Eng., of whom many readers may be familiar with. Besides his company's other building interests, he has written a 300 page handbook for architects, designers, builders and interested homeowners, that is filled with valuable information including tons of illustrations, of various building components and how they relate to the four major climate types. In additon, I believe you can get a smaller version tailored for your specific climate type. I know that there is one written for the South, so I assume there is one for each climate type. As an architect, I refer to it often and therefore, highly recommend it and their website as well.
"and Canada (If I recall correctly)."
Yep, covers Canada except for the far North with his (Joseph Lstiburek, Ph.D., P.Eng.) series of books.....he has to....he is Canadian. He worked with the Canadian Home Builders' Assoc and the R2000 program in the early 1980's. R2000 is the national high efficiency house system. Even all these early houses had air exchangers or more likely heat recovery ventilators in them.
I used to be an air leakage tester and certifcation inspector, researcher and "troubleshooter" for the program in New Brunswick.
Edited 5/14/2006 9:34 am ET by experienced
You'll note about the second paragraph I put in a statement about the assumed environment.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Sorry I missed that, but it certainly doesn't surprise me. I believe I noted your thouroughness in my message.
Building codes generally require either housewrap or tarpaper behind the siding. The main purpose of either is to function as a secondary water barrier. The air barrier bit is debateable. The wrap or paper must lap top over the bottom, just like shingles, and be flashed around windows and doors. The IRC, for some insane reason that I'd guess had to do with representives from the vinyl industry sitting on the code writing committee, exempts vinyl from this requirement.
In my view, the type of siding doesn't matter. Skipping the wrap or paper is simply unacceptable, unless, perhaps, you live in the desert. And even then, if you water your lawn with sprinklers, you should have wrap or tarpaper. That's because water moves from warm to cold and from wet to dry. Given that desert scenario, water would be driven into the framing if there was nothing to stop the movement. I'd rather see tarpaper there than housewrap. The reason is that housewrap passes water vapor, which I can imagine being created by the combination of sprinklers and sun. This water vapor could pass the housewrap and condense on the inside of an air conditioned wall, and now you've got liquid water stuck there. The point is that you've got to think your situation through in light of the laws of physics, without paying a lot of attention to marketing.
To take if further, cedar siding specifically is to be installed over housewrap or tarpaper per the Western Red Cedar Lumber Association's guidelines. Failing to do so constitutes an improper installation and exposes the installer and the builder to liability should the siding fail. I imagine other sidings have similar manufacturer imposed requirements.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
"Building codes generally require either housewrap or tarpaper behind the siding. The main purpose of either is to function as a secondary water barrier. The air barrier bit is debateable."
One higher end Halifax, NS R2000 builder uses his exterior building paper (sheathing membrane- Tyvek and the like) as his wall main air barrier. It is sealed to the foundation through the sill plate (mud sill) foam gasket and by the use of acoustical sealant. Windows/doors are sealed at the exterior also with acoustical. While framing at the highest wall/ceiling junction, a narrow piece of Tyvek is installed between the 2 upper wall plates. This is then sealed to the outer tyvek and to the inner ceiling or cathedral ceiling polyethylene air/vapour barrier.
He has won the NS Home Builders' Association "Tightest House Award' 1 or 2 years. It's done this way as it keeps the wiring, plumbing and drywall trades away from the sealed outer layer. His thinking is: The most holes created in houses are in the outer walls (his men installed/sealed the windows) and if you only have to deal with a few wiring and plumbing subtrade holes through the outer sealed layer, then you're way ahead. Letting them free on an interior air barrier is a headache. It also eliminates the pains of sealing at the rim joists from the interior and is even simpler than the rim joist wrap technique!!
Would like to see these houses ACH's measured after 10 years or so.
No question that it can be a valuable air sealing tool. But the way it's usually installed, house wrap does no better than tar paper as an air seal. And tar paper offers some advantages in typical installations that house wrap doesn't.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Properly installed, housewrap makes a big difference.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Properly installed, housewrap makes a big difference
Yeah, but that takes a bunch of tape over all those hammer-tacked staples <g>.
Do some remodeling where the stuff has been put up i nthe last few years, and it looks like sheesecloth (pun intended).Occupational hazard of my occupation not being around (sorry Bubba)
I believe you. I just don't see it done very often. It's hard enough to convince subs that they need to flash the windows, never mind taping the Tyvek.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Andy:
Just talked to the R2000 builder previously mentioned. He's had to change techniques due his company's expansion and loss of some of the quality control......he's not on site much anymore. He subs out most things now including his insulation and AVB so does not want a poorly sealed air barrier under the siding where he can't get at it if it needs remedial work to meet the R2000 ACH requirement of 1.5 at 50 pa. He did say thougf that when he was using the exterior air barrier, it was no problem to beat the requirement by 50% (.75 ACH). He won the tightest house award three years running up to 1999 with the best being .25 ACH!!!!
It seems like in the approach you're talking about (V.B. under mudsill and back in over top plate), the V.B. would be on the wrong side of the house for your climate- is this not an issue because tyvek/typar isn't really a V.B.? I like the method for sealing up, and exterior sealing would avoid some problems like electrical box holes. It just seems like any air moving into the wall in winter would cause moisture problems, unless it could easily dry to the outside.zak
"so it goes"
No, Zak, it isn't an issue. In the method I was mentioning and another called the "rim joist wrap", the tyvek/typar is permeable and doesn't cause a problem. There is even a way to do the wrap with poly with an 2" inset rim joist and a layer of 2" foam covering the poly to keep it in the "warm zone", but it has fallen out of favour due to the appearance of tyvek et al.
Edited 5/16/2006 7:14 am ET by experienced
.25 at 50Pa? That's impressive.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
In my experience, only one other was that low. My partner in the small construction company tested a homeowner/builder's barrier at 0.25 ACH at 50 pa. The guy was an electrician- would imagine his electrical work was something else to behold with all wires run parallel and spaced, and stapled properly, etc!!
Yeah. I'm more used to seeing 16 ACH @ 25Pa!Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Thanks for your reply. I have lurked here for a long time and respect your knowledge. When reading the archives about house wrap it did seem that the opinions of paper fared better in performance than Tyvek.
This is a silly question but would you put paper on a wood shed to create a moisture shield? It is my summer project and I want to make it as weathertight as possible. The current wood siding as just rotted away.
Yes, I'd put tarpaper on a shed. The stuff is cheap, the benefit worthy. It's a no-brainer.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
This could be an interesting threat. It seems to me that the house wrap is unnecessary. SHOCK! Blasphamy! But how many people just have these thoughts becaseu ... well, this is just the way it is done.
Well, if you have a vapor barrier on the inside of the walls, keeping mositure from washing, bathing, breathe etc from getting into the wall, what are you really trying to accomplishing by wraping the house again? You might even trap moisture between teh two (yes Tywek is not a barrier, but) . If you install your siding correctly, flash your windows correctly and keep your house painted, how much moisture gets behind your siding. And if it does it will dry to the out side.
Ok, insure against poor building pratices. If so, that is a sad testimony for the quality of builders.
So... you're saying... flash the windows to the sheathing?? Details please.
david, well I won't be specific but it can be done. For example, if you have Z flashing over a window the small gap between teh siding above teh window and the window is protected. Teh house wrap really is irrelevant at that point.
As for house wrap or no house wrap, I don't claim to be an expert. I was musing out load. However, I have worked on many 30, 40 and 50 year old houses with no house wrap! Never seen a problem with the siding or sheathing, with the exception of cases where windows were not flashed. But again that is not a house wrap issue.
So house wrap or no house wrap? I just don't know if it really is necessary. I would be interested in TRUE experts on the subject, and not just words from builders who really are just parroting "that is the way we do it (read in here . . . "so there must be a good reason")"
I just don't know, but I have seen plenty of houses without wrap.
And one more thing. People ahve rasied teh air infiltration issue as a reason for teh wrap. I think I can see this to a very small degree. And perhaps that is the number one reason for it and not moisture issues.
I agree with you Mr. DoRight!
<!----><!----><!---->
“The Miracles of Science” hehehe…..
<!----><!---->
Miracles? Like Astrology? Or Science? Like Astronomy?
What do you want on your house? Fact or Fiction?
<!----><!---->
I think “The Emperor has no clothes” and it is pure salesmanship of an unnecessary product. I see it cause more harm than good. It looks like it is used to cover-up poor quality sheathing applications by the installers. I prefer to call it “Eyesore Wrap”. (Except when it is put up so poorly that it’s an eyesore too.) Some people think it is good enough to use instead of a proven moister barrier….behind stucco and Hardie……. I hope they will let us know what they think later.
<!----><!---->
The only thing I see miraculous about it is that so many people buy it.
I was made a believer when we resided our house. Removed the old punky hardboard and put up new Masonite (which is holding up fine, thank you). Added Tyvek housewrap, well-taped, under the new siding.The difference in terms of detectable air infiltration (eg, air blowing out of electrical outlets) was remarkable. The winter comfort level in our dining room area (northwest exposure) improved significantly.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
she stated that the builder told her that they would not put any housewrap on her home at all - just caulk the sheathing and put the vinyl siding over it. I was a little shocked at this and wonder if having no wrap at all is wise.
I live in a house built about 20 years ago. It has some paper.
While it was built poorly it is solid and won't fall down around itself.
The builder who built it would now like to deny that he built our subdivision as he's building a new one around the corner. It's much higher end than this one and he would prefer to forget past mistakes. He uses a new Corp. name for each subdivision.
Anyway, in the new project he offers " Super Sealing" where you can get a " Better job than with Tyvek" by caulking the plywood seams with a little painters caulk.
A neighbor of mine moved from here to there and has had aton of problems such as damp drywall and taped joints coming apart.
No tyvek with vinyl siding? Sounds like a ton of problems would arise. With a good job done on hardi-board or other form of siding..the need for tyvek does seem a little wishy washy. The points some other people have brought about regarding tyvek trapping moisture probably occured from incorrect installation. Tyvek won't warranty their product if it is installed incorrectly...i.e. correctly lapped, using the correct tape and flashing details. Yes flashing details are probably the second largest problem with vinyl siding applications. However has anyone taken a hard look at vinyl siding? The number one probelm is the nature of the material itself. It actually has weep holes in it to allow moisture that gets behind it a place to get out. So not doing tyvek behind vinyl siding seems ridiculous.
It is because she is talking to hacks about building her house. She is apt to find many other shortcuts in their methods
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
It's funny that you say that. She researched the big name home builders in our area and the ones with the least amount of complaints are the builders she is considering. If it was me, I would probably go with someone that builds three or four houses a year than someone you is doing whole deveolopments. Of course, it may all be a crapshoot. If the consumer doesn't know how a home should be constructed, how would they know something is not right.
Too much work for me! And it kinda takes all the fun out of getting a new house.
Think for a minute about what it takes to be the biggest builder in a given area. It means that you will be building the greatest number of homes. To do that and make a profit, you will be shaving someplace. minimizing quality down to the lowest common denominator and still passing code ( and remember code is the minimum acceptable trange of work for that arrea)The Ford Escort was for years the largest selling auto on the planet. It provided transportation, and was affordable, but I never heard any owners bragging about any one of its features being the best...Same with houses. A builder can decide to aim for being best, or the most, but if he is going to make a good living, he is unlikely to be both
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I would look into Tyvek Drainwrap if you choose to go with the Hardie siding. Typically used in stucco and stone applications, it has a crinkled finish that provides a drainage plain in situations where the veneer in applied directly to the sheathing. (Regular Tyvek works great with brick, as there is typically an 1" or so between the brick and the sheathing.) Condensation can run freely down the face to the weepholes. Since the fiber siding is nailed dierectly to the sheathing, it can trap moisture that would normally run down the housewrap where airspace is available. The wrinkles in the Drainwrap, however, allow a little room for water and air to move behind the siding more efficiently. I have even seen some builders use lathe strips/sleepers (1x2s etc) behind cement siding to provide such a drainage plain/ airspace behing the siding. The caveat to this however, is that the siding (being rather brittle) is far less durable without a solid continuos backing.
Hope this helps-
What you are saying makes total sense. Now would it make sense if I requested it from the GC? In other words, is this a normal practice or would I have to request that it be done this way and give full detail on what to do?
Will this rippled Tvek under the slats have a lot of holes due to attaching the slats? And can this be properly done on dormers where there wouldn't be leaks up in those pesky corners where the snow gathers and melts during the thaws and ruins my dining room plaster ceiling that I never got fixed because its plaster and everyone wants to tear it out and put drywall....oh, sorry.
Edited 5/15/2006 8:54 pm ET by AcCable
mallard:
You posted "The caveat to this however, is that the siding (being rather brittle) is far less durable without a solid continuos backing." with regard to using 1x2 sleepers behind the siding (assuming you are talking about a rain screen wall).
Is this brittle nature really an issue? I suppose if someone really cracked a baseball into it?
Secondly, does anyone really build rain screen walls? Clearly expensive and does it really buy you anything?
And are they a superhighway for carpenter ants to really make tracks behind your siding?
I just said that I've seen the sleepers used (once to be exact). I only mentioned them as their purpose is the same (to some degree) as the drainwrap. I ended up using the Drainwrap on the shop that I just built. I'm not sure if it was worth the extra 50 bucks more than regular roll of Tyvek, but its advantages seem logical to me- what do you all think?
Yep!!! It's code in my area. While taking my daughter to the doctor, this AM, stopped on the way back to take pictures of a new house construction just a few km. from me. This the heaviest strapped rainscreen I have ever seen, about 25% short of being full wall sheathing. The retiring gent is probably 65 or so and ran a construction company all his life so he wants this one done well. He's installing 5" exposure eastern white cedar shingles for siding: it's strapped horizontally over 1.5" foam sheathing with 1"x4". He could of used 1"x2", IMO.
In our conversation, he revealed somthing to me I hadn't known before. As a child in the late 40's in Fredericton, NB, he would get to visit job sites with his father (the accountant for a construction company) to deliver pay envelopes. He remembers seeing strapping for siding on some homes!!!!! Maybe we're just re-inventing some things. I know some Quebec builders were using a rainscreen in the early 1970's.
Edited 5/16/2006 12:25 pm ET by experienced
Interesting. But with horizontal strapping you don't get teh air flow that a classic rain screen wall provides. I think FHB mag did an article on this some time ago.
Not the best but with some air gap and the winds we get here, it'll dry out fairly quickly if water/condensation is there.
On the issue of an open top to the vertical rainscreen strapping: Most say to close off the top since this ends hidden up in the soffit. This creates a vapour chimney with air/moisture that ends up in the attic if it has designed air channels to connect soffit venting to ridge/gable end vents.
I don't recall, but did not the FHB article mention a top vent? Curious.
Yes, there's a top vent. The rain screen either feeds into the soffit, or dies into a rabbeted trim board. With the rabbeted board, you don't bring the top of the siding or the furring quite to the top of the rabbet, so air can flow.
Actually, I don't think the upper vent is needed. The real benefits of a rainscreen are that it equalizes the air pressure on both sides of the siding, keeping out wind-driven rain, and that it provides a capillary break. The top vent shouldn't matter in either case.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
On the topic of siding ventilation, I recently renovated my residence and installed cedar siding as the new exterior skin. To ventilate the siding, I installed vertical 1x3 treated wood spacers at 16" O.C. over Tyvek on the exterior walls. Fully primed cedar siding went on top of that. For the ventilation screening, I cut a 36" roll of metal screening into three 12" rolls. I tucked about 4" of the screen roll under the bottom end of each 1x3 spacer, letting the rest hang down from the spacer end. This was repeated at each spacer along the entire length of the wall or until the roll played out.
Just before installing the first piece of siding, I folded the loose hanging screen edge up and back over the 1x3 spacers and tacked it in place at each spacer. Locate the nail so that it pins the loose hanging screen and the new fold at one time. Be careful not to crimp the newly bent material, so the metal screening will resist the bend and attempt to bulge out between spacers. The first piece of siding was then placed into position and when correct, pushed into the 1x3 spacers and nailed into place. This forces the bulging screen to flatten against the back of the siding. The metal screening constantly pushes against the back of the siding and the Tyvek, continuously sealing the gap, while creating a generous 3/4" x 12" screened vent at the bottom of the siding.
I'm sure it is obvious why the screen cannot be crimped and equally obvious that fiberglass screens don't have the spring to keep them in place and will not work. One bit of advise: when rolling out the 12" screen, keep it flat and level since wrinkles will affect the seal made against the back of the siding. But with the relatively stiff metal screening, this is easy to control. This method proved to be very inexpensive, easy to install, quick and effective for me.
Sounds like you did an excellent job.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
On the top venting of rainscreens:
Guess I was remembering research notes on the Pressure Equalized Rainscreen (PER) as recommended by the Institute for Research In Construction here:
Compartmentalize the air chamber.The locations on a building façade exposed to winddriven rain that require pressure equalization to achieve rain penetration control include building edges, parapets and architectural projections. Consequently the air chamber needs to be divided into smaller compartments at these locations while larger compartments are usually sufficient in the centre of the façade.
Introduce sufficient venting in the rainscreen at the bottom of the compartment.Traditional drainage openings in current wall systems may not be sufficient to provide the necessary venting for pressure equalization. Dynamic pressure equalization likely requires more venting of the rainscreen than static pressure equalization. The vent holes must be designed to let in only air, not water, so they must be shielded from direct water entry.
Interesting question: Does the rainscreen, where a 3/4" or better standoff is used, create a fire hazard, similar to unblocked balloon framing?
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Dan:
My code book (Canadian) says that narrow cavities up to 1" do not have to be firestopped.
Yes, I would think the top vent would not be necessary either. The point is you have drainage and secondly you have air which can to exchanged with the outside air, al be it slowly.
Doright, I would think "corevent" would be a perfect product for both top and bottom.
blue
Corevent or something similar is what the FHB article on rain screens used. That was about 3-5 years ago.
I edited the FHB article on rain screens, and built my house using it. The trick to keeping out the bugs is screening the bottom. No big deal.
Flashing the windows is a bit more challenging, but not bad. The extra labor was a day or two. I used mason's lath as furring. Cheap as it gets.
Now, since I used HardiPlank, it was probably overkill. I'd definitely do it though behind cedar. Should help to keep the paint on, and the water out.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Thanks Andy!
As for bugs, what screening material did you use? Do you expect it to breakdown over time? Did you use the same material at the top of the wall (I think if I recall your article you had a vent at teh top as well).
And why exactly would a rain screen be overkill with hardi? Just not a rot issue? I would still think mositure could force the paint off teh hardi.
As for triming windows, doesn't the furring push all the trim out? Did you rabbet it or just go thicker?
Regular old plastic window screen. With no UV exposure, it ought to outlast me. Aluminum or bronze would work too.
Yes, the furring pushes the windows out. Best solution I know is to fur them out with plywood. As my furring is about 3/8 in., 3/8 ply works fine.
I recently learned a slick way to flash cased windows from a Jeld-Wen troubleshooter. He used spray adhesive to adhere coil stock to the back side of the casing legs. The coil extends out 4 in. or so, and the head flashing goes over it. You could probably do something similar using Vycor.
I tell ya, all you need to be in this business is smarter than the wood. Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
You mentioned window screen. I am not sure you were replying to one of my posts or not. But since you mentioned it, how do you use flat window screen to fill the 3/8 inch gap at the bootom of your screen? Do you first staple say a 12 inche strip along teh bottom of teh sheathing, then apply your furring and then fold teh screen up over teh furring strips and staple it? I would not think too many insects would push up through that.
Yes, I do the screen just as you say.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
In answer to your question, I did not attach the screen with any fastener at first, other than pushing it under the end of the 1x3 vertical spacers. Friction held it in place at each spacer while I rolled out the whole wall, stuffing about 4" of the screen under each spacer. I suppose you could staple/nail/tack the screen in place, but I chose not to, since this limits the possibility of making adjustments to get the screen material smooth and flat after you have rolled out and stuffed every spacer down a 50' wall, let's say. Smooth, level and flat makes a better seal, so the ability to make final adjustments in a long run is important.
When the hanging screen was level, flat and without wrinkles, but not permanently attached, I lifted the loose screen end (8" +/-) hanging directly below a spacer and wrapped the screen over the spacer end. I checked to make sure all the slack was out of the screen that was wrapping around the spacer end and laying on top of the spacer. With the screen held against the spacer, I nailed through the folded screen, the wood spacer, the screen under the spacer and into the sheathing. This attached both ends of the loose screen in one operation and created an un-crimped bend in the screen between spacers. When the siding was applied, this springy bend would push at least 4" of screen material against the Tyvek (sheathing) and the back of the siding, forming the seal.
If the above is confusing, I suggest you re-read my first description very carefully and then read the above again as a review. I think that will tie it all together. Thanks for asking and I hope this addition cleared it up.
RB
Instead of 3/8 ply to fur it, I use 2 layers of felt. Seems to function well under any siding.
View Image
Troy Sprout
"Don't forget the screws"
Edited 5/18/2006 5:18 am by Hackinatit
Vertical membrane joints? I've read that it works, but I don't dare detail my wall sections with vertical joints. I have also read where some roofers attach their roofing felts with vertical joints. It flies against every bit of logic I know. I would be very interested in learning how it works and why vertical is better than horizontal.
The wall barrier is always joined horizontally.
The vertical strips are two layers of #30 felt applied over the studs. They serve the same function as firring.
Roofers can run vertical felt if they overlap the seams 6" vs 2" for horizontal. It's in the directions for underlayment lap joints to join two ends of a run.
There are times when situations/weather make the vertical underlayment a better option.
Troy Sprout
"Don't forget the screws"
Thanks for the reply. I just want to be sure I am understanding. Firstly, I assume that you have some sort of solid sheathing (plywood, etc.) under the felt paper in your photo. What makes me verify this is your comment that the furring was applied over the studs. In my literal mind, I began to visualize the felts nailed to the studs. But I'm wrong, right? From the exposed nail heads in the felts, this appears to be the conditon.
Next you run a layer of horizontal felts over the sheathing and on top of that "at the stud line", you run a furring strip made of folded felt paper, creating a ventilation space at the rear.
I'm glad to see your last sentence where you say something to the effect that the practice of running vertical roofing felts depends upon the location and weather. My state is on the Gulf, and although I am inland about 3 hours from the water, during Katrina we experienced Catagory 1 or 2 Hurricane winds, resulting in lot of damage throughout the state. So living in this location, you can understand this practice is very foreign to me.
Thanks for the explanation.
RB
"Next you run a layer of horizontal felts over the sheathing and on top of that "at the stud line", you run a furring strip made of folded felt paper, creating a ventilation space at the rear."
Studs, 1/2" ply sheathing, horizontal felt underlayment, doubled #30 felt strips over the stud lines (not folded as that is difficult to lay flat), siding.
View Image
View Image
View Image
Troy Sprout
"Don't forget the screws"
Edited 5/31/2006 4:24 am by Hackinatit
Edited 5/31/2006 4:25 am by Hackinatit
Edited 5/31/2006 4:26 am by Hackinatit
Thanks for the pictures. Now I understand. Seems like you got it covered! - Literally!
RB