What type of building system would one recommend for an area that regularly has high heat and humidity but also gets below freezing temps during the winter?
I would love if this topic became a long winded debate discussing the pros and cons of different types of materials and building systems.
What people really don't take into consideration is dew point, if your wall system is subject to long periods of very cold temperatures, you will want to consider this when designing the wall system. If you only have mildly cold temps that don't last very long then I kinda doubt its worth worrying about. The upside to cold is that humidity levels drop as the temperatures do so I would guess that so long as your walls can "breathe" and quickly release moisture you are fine.
Dew point is basically the point where the temperature in your wall is below freezing. This is the point where water will condensate. So if your dew point is at a surface transition like where insulation meets poly or sheeting then the moisture will condense on that surface thus causing mold etc.
I would be that a cobb/claw slip application would be perfect for your climate but someone with more direct knowledge would better answer that.
This map is the one that building scientists use to define broad climate zones. http://www.buildingscience.com/doctypes/enclosures-that-work/etw-building-profiles
Allison Bailes has a great blog on climate zones so I would advise people to read it if they are unsure what climate zone they are in and how much temperature and humidity its associated with. http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/59387/Do-You-Know-Your-Building-Science-Climate-Zone
Building codes are based off of this map and I recommend people learn their building climate zone when seeking advice about building in a certain climate. http://energycode.pnl.gov/EnergyCodeReqs/
To me, "humid temperate climate" describes all of N america except the desert southwest and the tip of FL. I feel strongly, that all new homes should meet the current minimum International Building Codes relating to Airtightness and Insulation. The map I linked to is based on the 2009 recommendations. The current 2012 IECC has some fairly important updates.
This subject is a tricky one because there are so many physics at play, so many materials to choose from and so many ways to put the so many different materials together. I think its tough to make sweeping, generalized recommendations for such a broad topic. I believe that almost any material can be made to perform well if put together appropriately.
As Ive said many times here, dont focus on materials so much that you lose sight of the big picture. In my opinion, reducing energy use while obtaining healthy indoor air quality should be the most important goals when it comes to making a more environmentally friendly and healthy home. This approach can also pay off with reduced monthly energy costs and possibly health costs.
Its also common to lose focus of the big picture by focusing too much on the wall design. The exterior walls of a home are but one small part in a very big picture. Take a balanced approach and address the entire building envelope as exterior walls are usually the easiest details in a house. Its all the transitions and connection details that usually have so much room for improvement.
I list "vapor permeability" last on my list of the Top 3 ways water destroys our homes and buildings; http://wncgreenblogcollective.wordpress.com/2013/12/29/the-top-3-ways-that-water-destroys-our-homes-and-buildings/
Thank you Will for using "vapor permeable" instead of "breathable". For those looking for breathable walls, I think vapor permeable is a better term and I explain more about this here. http://wncgreenblogcollective.wordpress.com/2013/11/04/should-we-eliminate-the-term-breathable-from-our-discussion-of-walls-and-buildings/ While I dont say we should never use the term, I think its too confusing most of the time.
At the end of that I enclose a link to defining perms. Perms is how we describe how vapor permeable a material is. Here are some examples that relate to another permies discussion going on and is probably the juiciest area open for debate.
Polyethelene plastic sheeting; .01 Perms
OSB sheathing: 2 Perms
Plywood: 10 Perms
Building felt/Paper 30 Perms
Tyvek housewrap 60 Perms
Polyethelene plastic sheeting used to be used as an interior vapor barrier but has fallen out of favor for all but the coldest of climates for obvious reasons. It traps moisture. The other products are all used on the exterior. Designers need to pay attention to the vapor profile which basically says how much drying potential there is in a wall or roof profile. I think its common for natural builders to just say make everything "breathable" but this can actually cause problems if its done in the wrong situation or application. I am of the opinion that as long as the wall or roof doesnt have two layers of relatively impermeable materials trapping a material that could rot, things will be just fine as long as it is 1. not getting wet from bulk water 2. doesnt have air leaks and 3. Isnt exposed to excessively high wintertime indoor humidity.
In an attempt to transfer some interesting discussion from the insulation thread I hope its ok to copy and paste two recent comments to what I think is a more appropriate location. Much of this discussion however is interelated.
I wrote :
As for Tyvek vs. building felt/paper I think it once again depends on the application. These are not products intended for airsealing and insulation. They are Weather Resistive Barriers WRBs meant to keep bulk water out of the house. I think we should move any further discussion about them to the new thread on Vapor Permeability in Temperate climates (which includes most of US). I must point out however, that Tyvek is MUCH more vapor permeable than most building felts. Some building scientists think that Tyvek is too permeable for most applications. I think both forms of WRBs can be useful but dont recommend tyvek behind real wood as the tannins have been shown to break it down (with no rainscreen). The jury is still out on fiber cement. I should also point out that almost all building scientists recommend rainscreens behind siding and masonry, for most climates, and most commercial products made for that purpose are made of plastic. That being said, I think the best rainscreens use furring strips (some are plastic) for siding applications. Still, depending on the application, a plastic WRB or rainscreen can add years or decades of life to most cladding systems and paint jobs.
Home wrap (tyvek) is I think as much a victim of aplication as most materials. CCHRC is doing some really good research and with their arctic wall it seems to be permiating the moisture quite well. I think part of the issue with tyvek is that you have the inconsistent poly later on the inside of most walls and so the tyvek can't compensate. The arctic wall has been used to good effect on passive homes in Europe as well so again I'm not against it's use so long as it's done properly.
Overlaying home wrap on top of exterior sheethimg is kinda counter intuitive, combined with the wood in surface contact I can't see how any moisture is able to permeate out of the wall cavity. Just a thought.
Here is a link from the CCHRC describing Sean's arctic wall reference: http://makinghouseswork.cchrc.org/2013/arctic-wall-is-a-new-energy-efficient-construction-option-in-the-interior/
I know I said that its tough to make sweeping generalizations on this subject but rainscreens are almost always a good thing to include in climates that see measurable amounts of rain. The best rainscreen article around is this one: http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-rainscreens
For those looking for more technical resources, Building Science Corporation BSC is the go-to resource. Start here and there are many other great papers relating to this immense and often confusing subject. http://www.buildingscience.com/documents/reports/rr-0412-insulations-sheathings-and-vapor-retarders/view
I'm willing to gamble that sandwiching two materials results in a higher level of resistance than the sum of the two materials individually.
In mixed and warmer climates, this wall is theoretically designed to dry in the wrong direction. In theory you would want the lower perm sheathing on the exterior to better resist inward solar vapor drive. This could also be a problem in cold climates (during the cooling season) with siding or claddings that are considered moisture reservoir cladding; stucco, masonry, fiber cement etc. Should be fine with wood though.
I would say above 60% year round. But I would go with thermal mass over permeable insulation in your climate. Cob and the like probably work stellar there.
TM can certainly improve energy performance and comfort in all climates when completely inside the building envelope (air barrier and thermal barrier). But to say that TM is on the same par with air sealing and insulation..? No way!!!
The real question for projects (other than heating appliances) looking to save energy resources with TM; is it cost-effective? Compared to air-sealing and insulation.. good luck.
Brian, TM does everything to promote health of a building and it occupants (when done correctly.) I would also point out that too many folks think "linearly" when they refer to TM. A timber frame is TM, as are larger masonry or cob core central masses in structures, that passes from foundation to the roof area. The list goes on and on, and not all that is TM (or should be) is the "exterior walls." The more I digest this subject, the only limiting factors to TM, is skill sets, fiscal assets, and choosing the correct TM, as almost every home I have ever been part of could (or did) benefit from it.
I would much rather have an all natural home that is a wee bit drafty in spots (which can be fixed) than any of the modern "air tight" plastic wrapped bomb shells that are just waiting to explode in some fashion in the next 40 year. It just is a ludicrous way to build, and anyone that promotes it really is not getting the understanding, or normative culture of Permies and the underlying building modalities we try to support in this forum...
As to the comments that what weve been discussing is not permaculture, I would love to hear more detail in what you disagree with. Air tight construction? Any plastic? Housewrap? Iam very confused what you are referring to as ludicrous.
I believe one of permaculture's main goals is to use energy efficiently. I dont see a wee bit drafty contributing to the cause. How drafty do you propose? So we only get fresh air from the drafts when its windy (when we want it the least)? Where should the drafts be coming from? Surely not the soil, garage, combustion appliances, mudsill, window frames, crawlspace, attic, through interstitial cavities, etc..? Any uncontrolled draft is wasted energy and increases the risk of damage (and mold) from water intrusion and moisture deposition from humid air. Its extremely confusing to suggest we build things drafty on purpose and then fix them. That seems to be the more ludicrous approach to me.
Yes, a post thread on the realities and health benefits of TM would be good...
I still don't think you are getting the real "heart and soul," of what permaculture is all about...
You wrote, "permaculture's main goals is to use energy efficiently..." Yes it is important, but main goal? Not at all. I am not sure if you think most of the homes you describe, or show on your web page are "permies" style homes or not, but I can tell you from growing up in this culture...they ain't, sorry. I believe your homes are well built within the parameters of what they are, but I do not see any of them lasting much longer than, maybe at best, 75 years without major (and minor) interventions that will require more technology, and industrial product to rectify their challenges. I certainly do not see them lasting 300, 600, or a 1200 years, as do many of the styles I study, promote and design. That is "permies architecture," at its very best!!! Sorry if this sound to "preachy." You add great stuff here, yet often it come from an "angle" that just isn't germane to what permaculture is.
The current fad in "building science" is all about sealing and insulation right now and that's great but it's still ignorantly based on the idea that a structure should be heavily grid dependant or at the least mechanically so.
I think HVAC systems begin to lose a lot if their overall value when a building is well balanced and uses passive solar design. I'm still a fan of HRV systems but a building can have a passive design that allows air to naturally move in convection loops within the envelope and that is where TM comes into play as well as working as a storage and buffer for solar thermal inputs.
I try my best to present the information Iam familiar with in ways that can be applied to all building methods. Its tough for my preferences not to show through but I feel most of what I present here are broad techniques and ideas that can be applied to any particular material or method.
My biggest problem with your comment Jay, besides the subtle misquotation, is that you imply energy use is not at all one of the main goals of permaculture? The energy use of our society is one of the most important areas that we all need to improve on. Reducing energy use from the trifecta of Transportation, Food and Buildings is probably the biggest challenge facing our civilization. Ive dedicated my life and career to reducing the impacts of the buildings portion of this triangle and most experts point to it as being the biggest user in this dirty energy equation. Permaculture is broad in scope but I firmly believe that using energy resources efficiently should be one of a permaculturist's main goals. I strongly believe reducing energy use is one of the most important goals for all individuals and society. By focusing on a building's energy use, you can also increase its durability, indoor air quality and comfort while reducing the monthly energy costs and very substantial hidden environmental costs. The vast majority of a building's environmental footprint is from the monthly, energy costs NOT the building material's environmental impacts.
Didnt ask for an evaluation of the homes on my website but I appreciate the kind words and publicity. I dont think Ive linked or posted directly to any of my projects as examples of permaculture. The moderators are kind enough to let me post links to blogs and specific areas of my website that I hope helps educate people on specific areas of detail, mainly building science related. In my projects defense, they all feature solar energy with water, energy and material conservation strategies that should be considered by all those building or rebuilding especially those interested in permaculture. I strongly disagree that they are somehow less durable and would of course argue the opposite. Too bad we cant fast forward for proof..
I was hoping to get specific answers to questions that I think are fundamental to Jay's views on these subjects and but I realize they are not easy ones. I think we agree more often than not. Perhaps Jay can enclose some links to projects claimed will last 1000 years with no major or minor homeowner maintenance or intervention? I have to point out that if the buildings that last 300 to a 1000 years ignore monthly energy use, they will probably have done a tremendous amount of environmental damage (mtn top removal, coal ash/toxic chemical spills, groundwater contamination from fracking, acidification of forests and streams etc) which is not permies at its very best to me.
Sean, I think "fad" is a terrible choice of words for building science's view of air-sealing and insulation. Air-tight and super insulated construction was pioneered by hippies and owner-builders back in the 70s energy crises. Since then it has only become more popular and important. I think TM used to be viewed "just as important" as you put it but has been proven by science and research to not be a major player in most high performance homes. I agree that adding more mass is necessary for passive solar homes, thats basic passive solar design. For most homes however, adding what is needed beyond typical construction and furnishings is a waste of money and resources. Of the many things that are more important than TM other than air sealing and continuous insulation: fenestration, HVAC efficiency, water heater efficiency, other appliances efficiency, lighting efficiency and roof color. In a well balanced, high performance home all those things should be considered before adding additional TM than what is needed in the construction anyway.
I also disagree with your implication that building science is pushing us to be more dependent on the grid. I think building science is the main reason that our countries residential energy use has stayed the same for roughly 30 years despite an increase in population and house size. Most building scientists and high performance homes are moving in the direction of net-zero which is cleaning up the grid in major ways while offering the opportunity to make a dent in the transportation side of the equation with PV powered vehicles.
I think current practice is a fad because it is largely discounting passive solar which is definitely superior and not much more expensive then a simple higher performer upgrade to the existing. It's all progressional but why would you want to go to seething that was current in the 70s when we have so much better and proven solutions available now?
I think when you build up to code with building science suggested best practice, you increase resiliency from power interruption. This is especially true with air tight, well insulated passive solar of course. Care to enlighten us on the details?
To me, the fad is wasting energy and I think its disgusting. Especially considering Iam about to take a 20 minute hot shower with water heated by mountain top removal mined coal.
The place where I think your not following is that we're discussing building practices that go beyond just air sealing. "Best Practices" don't actually outline "the best practice" they outline the current fads that some governing body has decided to endorse no more and no less. Minimum code requirements across North America are way out of date, way too low in the performance department and HEAVILY politically influenced following that as a best practice I largely ignorant when we can do so much better for relatively little extra input.
Thermal mass has been discussed to death. If you don't see it you don't see it. Passive solar, same deal. Anyone who is building for efficiency and not accounting for passive solar as a foundation of their design criteria is an idiot. It's simple free energy input that has been used, tested, proven centuries ago. Why you would go through the expense and effort to build a high performance building without accounting for passive solar and thermal mass as part of the design is plain foolish. Passive solar and thermal mass can often be accomplished for little to no extra cost over typical building practice so why one interested in permaculture would neglect to address it is beyond me.
The ideas and information from the 70s is 40 years old, we can do so much better with lower impact now why wouldn't we?
I think I am probably the one "yoked" with saying "airtight is unhealthy," which was taken way out of context, and in a direction I never meant.
For one, "airtight" is bad...but, "draft proof," is excellent. Most (all?) well built contemporary natural and/or traditional buildings have both well thought out TM and PS. It is only common sense, and they are sustainably "draft proof" within reason, while still staying permeable to indoor moisture production.
I am not sure why so many contemporary design-build companies insist on jumping on the corporate bandwagon of LEED standards, Code, and other "industry driven" allegedly "green" building modalities. I find few that are actually "green" at all, and for one, have stopped using the expression as much as I can as it has become so "white washed," by media that seldom does it mean "green" at all. Vinyl siding, plastic measured in tons, petroleum based products up the 'wazoo," heavy industry manufacture materials, and heavy dependence on "grid tied" technology that must be maintained, serviced and replace just to make the architecture work properly is the farthest from low carbon footprint, environmentally, and "whole world" sustainable architecture as you could possibly get. Nevertheless, this is what is being promoted as "green." Sorry, don't thinks so, and certainly not within the context of permaculture or even good practices in healthing methods of building.
The fallacy that PS is not applicable in all architecture as written, "Many may not fully embrace it but not all sites and clients are the right fit for it." is just silly. It is one of the fundamental things I have tried to (not always successfully because of the silly notion it can't be done always) incorporate in any design. If you simply include TM into an attached solarium, or greenhouse (or one close by) you can add PS to any architecture or even a community-collective of buildings, where not only do you receive solar energy gain, but also a solid 3 season space, growing capacity for food, waste treatment, and the list goes on. Solariums, greenhouses, walk-in vivariums can be added effectively to just about every piece of architecture I have seen; both vintage and contemporary. So yes, clearly passive solar and thermal mass both should be in "all" environmentally sustainable architecture design, even if the client chooses not to use it, I ethically find that I must provide the matrix in the design configuration. I would add that independance from the grid should, at minimum, be planned for all new architecture, even if it is not within the current project budget.
I would also point out, at this juncture, that I have never said or implied that energy consumption economics is not part of "permaculture" I have said that we approach it more holistically and with less dependence on "industry and technology" whenever possible...like TM and PS design that Sean just referenced again, (and well I might add.) I would also point out that it is the "first world" countries and those trying to be like them, that are having issues with the way they consume energy (and waste it.) What do they all have in common? A disconnection from the environment around them, shipping building materials thousands of miles, and an extreme dependence on industry to build anything...including their allegedly "green" buildings. Sorry that does not work for me, is not permaculture, or even common sense.
Anyone that claims to have "dedicated their life" to healthing building practices would not promote those systems even a little bit, and I still shudder whenever I have to use these materials in a design for whatever reason. If we, with just the technology and social understanding we have from our ancestral building systems adjusted our lifestyles (and the fundamental way we live in general) we would all have more energy than we would know what to do with. I have friends, and have built homes that routinely open there doors in the dead of winter when it is well below freezing out just because it is too damned hot in their "well build" natural house for them, their animals and kids to while they are just moderately active and properly dressed for the season. Energy isn't the biggest issue as much as is our "normative culture," the way we act within our micro and macro environments and how we have been culturalized to “consume,” and perceive things. Energy consumption is a "hat trick" that we focused on way too much. Adjust your living style, and thought patterns to the environment your in, and you will have a paradigm shift in all your thinking...then again I live outside and sleep outside 360 days a year and use buildings for socializing and work.
I must also take exception to the notion that, "By focusing on a building's energy use, you can also increase its durability." That makes no sense? I could build a structure out of factory farmed and processed wood and concrete, wrap it in plastic till its air tight and seal it with plastic foams and it would be extremely energy efficient, (as long as it lasted) none of those make them healthy to live in nor durable. All the evidence I am seeing is they are anything but durable, especially when compared to most natural builds or vintage architecture.
"The vast majority of a building's environmental footprint is from the monthly, energy costs NOT the building material's environmental impacts," that would be true if you are just using statistics to arrive at that conclusion, yet when compared to other "natural systems" of building, and the way many forms of architecture are treated and acted upon by contemporary "consumer" societies, the stats start getting really shaky...quick.
Brian, if I implied that you are a bad builder, I apologize. As one of the moderators here, I had to look at what you designed, and build,while comparing it to what most in the "permaculture world" builds and lives in. They are not the same, by a long shot. Yours are heavily dependant on technology, industry, and modern unproven designs. Many of which I am tearing apart both metaphorically and in real life, all the time looking at all the issues with these contemporary concepts in architecture that just are not working as claimed. It's that simple. I don't need to test it, or think about it, or wait longer to make conclusions. It simple when I remove spun glass insulation, and house wrap and find commonly, rotting wood, and moisture issues; I can tell you that these concepts are failing it intent. When I look at the other systems and compare those "holistically" homeostatic natural building systems that are locally grown and built, there simply is no comparing which is superior in the bigger picture of sustainability and durability as many are built on the foundation of modalities that are ancient. Cob and timber framing are but one example.
Brian I have posted several projects on Permies that will last well over 300 years, are sustainable, and natural builds. Many that are outlined and showcased here will probably come close to that themselves with minor intervention that can all be done by the owners from materials on the land which the architecture sits. Since I am also a "Historic Conservation-Restoration" builder as well, I can tell you I see countless home, in the light of how they had been lived in, that did not nor would as you put it, "...probably have done a tremendous amount of environmental damage (mtn top removal, coal ash/toxic chemical spills, groundwater contamination from fracking, acidification of forests and streams etc.)" They existed before these rather nasty "modern and industry laden" practices even existed. I would also suggest that if we build this way, augmented with what we have thus far learned about natural building and sustainability, as well as good building science, we can look forward to homes that can be built by their occupants, from mostly the materials around them, sustainably without issues to HVAC because that too is made and consumed within the local environment.
Briain your notion that TM should be consider after, "air sealing and continuous insulation: fenestration, HVAC efficiency, water heater efficiency, other appliances efficiency, lighting efficiency and roof color," is one of the main reasons I say you are not getting the holistic concepts of "permaculture," and you still aren't. You may not want to, and don't seem to be trying, that is fine. We will still value your input, but you can expect this kind of push back from myself and other readers that are true permaculturist as long as you do. You alluded to the Hippie movement, "air tight" (again) and building science and how TM has been proven to be less important. That is all subjective views and research that I think I am more than qualified to question. It is not proven, nor even in context to what Sean, myself or others are saying about "natural building" which could also be called (though a longer name) "holistic, sustainable and homeostatic" building.
Having know some wonderful Building Scientist in my time, I will not lay much blame at their feet. I would also say that my views are fundamentally shaped by many of their teachings and writings, including that about "house wrap," sense it was one of them that said, "never on my house, good (healthy) architecture needs to breath..." (Healthing meaning for the structure’s durability and the living occupants.) I will say that most of what we are seeing in "green" architecture is definitely a "fad." Most of it is way outside the context of good "building science," and into marketing and industrial promotion of products that may be "forced" to fit a new criteria of "green," as they (industry) sees it. Net zero is another "buzz word," that has some merit yet is rapidly going into the realm of fad itself.
I make this entry, as a validation point not only about the leaders of this organization , but also for myself, to make sure what I thought has a foundation...it does IMO. I have been an opponent of LEED from the beginning. I have always questioned its leadership and underlying motivations, (and the "green"building movement.) I still contend that it is industry based "white-washer," and "policy hound" for commercial organizations trying to steer "green building." It is comprised of professionals with little or no foundation in the world of architecture, or "real green" architecture. What little environmental background that is present is "inbreed," and not with any substantial history in pertinent fields outside of LEED and the GBC.
This is but one more issue that I have with contemporary building methods being "white washed" as sustainable and "good practice."
LEED, its attempting monopoly on "Green" building, and where it came from.
Our guides to green building?
Not one green architect, natural-traditional design builder, ecologist, permaculturist, building scientist, in the group of leaders and founders of LEED.
FOUNDERS AND LEADERS OF LEED
CEO & Founding Chairman, "U.S. Green Building Council."
Formally of the large industrial machine that is the "United Technologies Corporation," a $12.5 billion company, in over 170 countries.
JUST SOME OF THEIR ENVIRONMENTAL HISTORY:
21 Aug 2012, by Ashley McCauley; Braumiller Schulz LLP "...United Technologies was charged with 576 violations of the International Traffic in Arms Regulations (ITAR) in connection with the unauthorized export and transfer of defense articles, and the unauthorized provision of defense services to multiple countries over a number of years..."
United Technologies to Pay Fines Of $5.3 Million in Pollution Case.
United Technologies Corp. resolved previously disclosed enforcement actions brought by the U.S. Department of Justice and the Department of State in connection with past violations of U.S. export control regulations.
18 Feb 2007, by Eric Gershon; Courant Staff Writer "...The U.S. Department of Justice had agreed to release Hamilton Sundstrand's parent company, Hartford-based United Technologies Corp., from a decade long federal consent decree that resolved widespread environmental violations at UTC, some of them at Hamilton. Under the decree, UTC paid $5 million in penalties and millions more for extensive environmental audits that uncovered further violations...Whatever its effect on the Earth, the history of violations by United Technologies and Hamilton Sundstrand was a major factor in this month's record-setting punishment..."
Senior Vice President, LEED, U.S. Green Building Council
Formally of SevenGroup, a leading industrial green building consultancy. He began his career as an opera singer.
J.D. Senior Vice President, Global Policy & Law
Formally stood 15 years as senior vice president and counsel with the Real Estate Roundtable
Chief Operating Officer, U.S. Green Building Council
President, Green Building Certification Institute
Formally of Emergys Enterprise Business Technology Solution -Services company, and Lenovo a Chinese multinational technology company.
Chief Financial Officer, U.S. Green Building Council (USGBC)
Formally of GeoEye, Inc., a commercial satellite imagery company. Varsity Group Inc., providers of outsourcing solutions for the education institutions. Installs Inc., Installer of satellite dishes, wireless internet devices and home theater.
Judith Webb, APR
Senior Vice President, Marketing & Strategy, U.S. Green Building Council
Formally spent 20 years with advertising, public relations and marketing agencies, advising public and private companies, and professional firms. She began her career in public and government affairs at Amoco Oil Corporation.
Senior Vice President, Community Advancement, Conferences & Events, U.S. Green Building Council
Formally worked as senior meeting & events manager of incentive and recognition at WorldCom Inc.
General Counsel, U.S. Green Building Council
A lawyer with a background in, a public interest law school. Hmmm, why not environmental law? Wouldn't that be more applicable to LEED.
Vice President, Organizational Development; U.S. Green Building Council
Formally of Catholics for Choice, and Interfaith Alliance.
Roger holds a master’s degree from George Washington University in political management and a bachelor’s degree from Bridgewater State College in political science.
Director, Center for Green Schools, U.S. Green Building Council
Rachel does not have a career profile before the GBC. Rachel has a Bachelor of Arts degree.
Senior Vice President, Global Market Development , U.S. Green Building Council
Peter does not have a career per se prior to GBC. He, it would appear, has left the GBC to become president of Green Building Certification Institute (GBCI) an independent, third-party organization committed to ensuring precision in the design, development, and implementation of the processes used to increase and measure green building performance (certification) and green building practice (credentialing). Of course all based on LEED principles, with full support of GBC, based in Washington D.C.. In other words, he is a primary lobbyist for LEED and the GBC.
Vice President, National Policy and Advocacy, U.S. Green Building Council
Formally, here again, we only have a varried history. Jason served in the Clinton Administration, in Intergovernmental Affairs, and as a reporter with the Connection Newspapers, where he covered state and local politics, real estate, land use, and community affairs, winning multiple awards. Jason does have a Ph.D. and a Master's degree in journalism and mass communication from the University of North Carolina at Chapel Hill.
From what I can see in the commercial side of the industry LEED is being abandoned by many in the industry because it's just way too top heavy and frankly it adds SIGNIFICANT costs to projects with little quantifiable return. Where I live the support just isn't there outside of some government projects.
I would say this. For me I tell clients that the first question to answer in the process is "how do you want the building to perform?" So performance drives the process for me. Having the ideal ecological etc solutions and a home you don't like being in long term is a non starter and turns others off the whole idea. Others might say people just need to suck it up and live a harder life but that's not a viable answer to adaptation of sustainability on mass. Life has to be enjoyable for the majority of people in order to have impact.
I generally don't appose many of the modern products or industry but I really want to be able to take everything that I can IN CONTEXT. So I'm positive about foams etc if they work best in context.
Many rebuttals to what you guys have said but I agree with much of it too. I love the big picture philosophy debate but think we should bring it back to the thread title which still has room for philosophical discussion and debate.
Jay, the draftproof versus airtight thing drives me nuts! What is the difference? I just cant recall where youve spelled this out for us in different threads. This is the perfect place to lay out your definitions (or educational/informative links) to the difference between airtight and draftproof.
Whether air exchange is controlled passively or mechanically is another topic.
I would classify the "arctic wall" promoted by CCHRC to be air tight but vapour permeable.
Brian, if we every did a project together...I for one would love it. There would be a complete spectrim of knowledge, great "checks and balances" and the client could ask "anything" between us and get a great answer (probably more than one )
I doing this one quick:
Back in the 70's when this "stuff" stuff all kicked off, folks started really wraping things up in whatever they could. Plastic sheet material became (still is in some areas) the go to product as it really stops the air flow when (at first) all sealed up. Alas, that proved to be a "no go" as it could not be (or would not stay) "all sealed up." Moisture got through and things....well...got "dank" quick. So "air tight" real plastic air barriers seemed like a good idea in theory, but did not work in the "real world."
Now we are in the 21st century, and taking this another step further. We have products like Tyvek (Dupont created, funded and research; with a giant lobbing force to promote the system) that is a multi million (I am looking for stats but they seem to be pushing the billion mark globally for this family of products) that are "supposedly permeable," allowing moisture vapor to pass right through. Read any of the original or current literature (of course from Dupont or there funded research) and you would think this stuff is better than "Gore Tex."
Here is the rub. Just like plastic, it may work in theory in the lab but in the real world...it seems to not quite live up to its claims. As bad a solid plastic? No, not most of the time, but not permeable by any measure. That is not coming form testing, that is coming from thousand of square meter observed and compared over the last 25 years from North Carolina to New England. I have spoken of the "tyvek suit" comparison (some try to dispute that) and I have made models and shown folks. It is starting to take hold, but not they way I would hope. That's o.k. as it is just a matter of a little more time and folks will start figuring this out for themselves. Moisture in vapor form DOES NOT pass through as claimed, it condenses and runs down the plastic, and/or wicks back into the insulation. Of course if foam is used there really isn't a need for "hose wrap" as the foam (if done properly) has sealed things up "air tight" and on the roof, I am o.k. with that, and some of the soy based foams as well. I am still thinking and digesting the entire foam thing... I even use probably too much of it for my own liking but I am figuring it all out. Still would like to avoid it if I can on projects, yet that is hard on many considering the R factor for per square meter of material and labor. I am on the fence with much of the foam thing currently.
Now, moving back into "air tight" vs " draft proof." I like the research (and I stress RESEARCH not proven facts or long term verification of effectiveness and durability) of what the CCHRC is doing. Great group, great work, yet much of it is "hypothesis" not yet even a solid "theory" and very challengeable on several fronts. One is, the "artic wall" concept. I love this wall and build very similar systems to it, and about the only thing I leave out is the "air barrier," which is either still plastic or related to Tyvek. If a wall is built well with a cold roof, tide into a "rain screen" outer wall system this can be both effectively "draft proof," very permeable, and highly resistant to weather driven moisture if done properly.
Now that should give the three of us (et al) something to "chew on" for a bit....
You bad mouth Tyvek pretty heavily and then praise CCHRC and the arctic wall which uses Tyvek. As Sean points out, the wall seems to be performing great with no measured elevated moisture buildup. This research suggests that the real world performance is accurate for tyvek, a material measured at 60 perms. The highly permeable Tyvek seems to be doing the exact opposite of what you describe, no?
As for the definitions.. How is draftproof different than airtight?
Brian, I think arguing that there should be no obvious holes in the wall system is kinda like saying cars run better on roads. We're way beyond that and the discussion is about the next level of thinking. The holes are a given, I don't think anyone builds a wall with holes as acceptable.
What jay said about plastic used inside walls it totally true. I don't care how many holes you have 6mm plastic is a junk solution.
I dont recall any question or thread on this site relating to the specifics of airsealing but many on insulation, thermal mass, passive solar design and permeability. If you are going to make these strategies pay off in a meaningful way, you have to achieve a certain level of airtightness. How airtight and how much outdoor air ventilation is whats up for debate. Fortunately, the blower door test creates a very simple metric compared to these other things and is probably the most important measurement when it comes to building an energy efficient home. Until people are regularly achieving 1.5 ACH50 or less on their projects, I dont feel we have come anywhere close to being past this issue.
If you are concerned with vapor permeability in temperate climates, you should be more concerned with how airtight the structure is as measured with a blower door test.