.

Issues with Manufactured Homes

Dr. Nabil Taha has over 27 years of structural engineering experience. Prior to opening his own engineering firm in Oregon in 1997, he was a Professor of Engineering at Northern Montana State University and at Oregon Institute of Technology. He has structural expertise in a wide range of building systems and can answer questions related to virtually any common building method. His focus is on green design and he is always willing to trying something new. Dr. Taha is dedicated to future sustainability through innovation; he creates solutions for beautiful sustainable and safe structures by melding old and new technologies. He loves a good challenge. He is Licensed in twenty three states and can design buildings and/or consult to assist with structural permitting in these states as well as internationally. As a prior College Professor, Dr. Taha is a teacher at heart. He loves to share his knowledge and offers educational seminars and trainings for the do-it-yourselfers and professionals alike. Dr. Taha's goal is to continue to grow and provide knowledge and services for those trying to make their dream project a reality. No project is too big or too small. For information about Dr. Nabil Taha and his engineering firm see www.structure1.com

Questions and Answers

Q: I'm coming off of 6 months of living without housing, and I'm still trying to find any mobile home or modular or pre-fab manufacturer that build without toxic materials. Have you come across anything yet?

A: We design modular homes without toxic all the time. Please contact Mr. Bobby Mick e-mail BobbymickATibuildor.com, (541) 882-2002 II you have additional questions.

Q: I am on a mission to build a sustainable and energy efficient home. I am trying to accomplish this in expensive NY with a limited budget. I am trying to find a reputable modular company or builder to see if this might be more affordable for me. Do you know of any here on the East Coast. I already have Go Solar for my PVC and their pricing lined up. I also need any info on the best rated Geo-thermal systems for my zone (bad winters) and what I should expect to pay to install this for my heating & cooling.

A: (John Connell) There are three reputable prefab companies that are very committed to building sustainably - two are modular companies and one manufacturers "smart panels". In order of average cost/sq.ft.:

Preferred Building Systems out of Claredon, New Hampshire makes a very nice super-insulated module. They are a tremendous value but you will need an architect or designer if you're hoping for anything other than a plain pedestrian design (see our contact numbers at www.2morrowstudio.com).

Epoch Homes, also in New Hampshire, is an older module manufacturer but about six years ago it was purchased by a Green Zealot named John Ela. John has completely reformatted Epoch and it now has a great reputation for green building. They give presentations regularly in Greenwich, CT where they have built a lot of homes. Epoch is a little pricier than PBS but they have been around longer. Here again I would suggest an architect but Epoch has been working with architects long enough to have pretty good instincts.

Finally, Bensonwood in Walpole, NH is the most advanced of the lot. This product is a bit more money but worth every penny. They are on a mission to build affordable green homes and they're getting better all the time.

We design and build all over the region and I always give the same advice about GeoThermal - use the best installers in your area and use the brand of equipment they're most used to servicing. It doesn't matter if you have the latest development in geothermal if your installer can't service it. GoSolar is a fine organization. Can't see you doing better there.

Q: Do you know of a company that builds modular homes that are eco-friendly? If you do, can you please pass on that info.

A: (Leon) Don Bradley, President of Solar Strategies, Inc., a home builder for solar homes for nearly 15 years has partnered with manufactured housing companies to offer low-energy homes whose energy bills do not exceed $600 per year. A four bedroom, two story home features energy efficiency features including double-paned windows, and R-21 (walls)/R-38(ceiling) insulation. A solar water heater, solar-electric roofing shingles, traditional solar electric panels, electric interconnection and inverters are provided. For further information contact Don Bradley at 610-574-3685 (cellular) or Scott Sklar at 202-347-2214 or at solarsklarATaolDOTcom.

The 2,300-square-foot Genesis is the flagship of a new line of factory-built homes by Champion Industries. Genesis features a double-height living area with mezzanine, three bedrooms and two baths, an extensive deck and an attached garage. Twelve of Champions 56 plants are being converted to produce the new line, built to meet local or state codes and marketed to home builders as a cost-effective, quality and time-saving alternative to conventional site construction. It will be up to the builders to pursue the Energy Star and local Earth Craft House program, which establishes standards for environmental quality, including criteria for clean indoor air, recycling and resource conservation. SWA performed the testing and inspections necessary to certify the show home's compliance with both programs, and worked closely with Champion's design team to achieve a cost-effective configuration of green/low-energy features.

Q: I live in New Jersey and I am thinking of building a green kit house, any recommendations?

A (Kelly): I know that there are kits available for yurts, geodesic domes, and a few other simple structures. You can find these through an internet search I am  sure. There aren't many kits of homes that are specifically "green" available to my knowledge. It is often better to design the house to fit the site and employ local materials that fit into a well-designed home for your specific needs.

Q: What is your opinion of yurts (Americanized version) for living in year round (in NE Minnesota - cold in winter, moderate snowfall, can be humid in summer)? I like the idea but wonder about the practicality (though the manufacturers say it is do-able).

A (Kelly): I like yurts and the feeling of the space inside of them. There are several manufacturers of these, and some of them do claim they can be used in cold climates. It's all a matter of insulation, so that is what you mainly need to pay attention to. I have yet to see a yurt that I would want to spend a cold winter in...but they may exist. You might see if you can get references to former customers who can can ask about their experience.

Q: My interest at this time is to find, or if needed create, a green kit home. I was building solar homes in Ca, in the mid 70's and now have a commitment to build green. However, my interest is in staying somewhat mainstream. I wonder if you know of anyone who has a green kit package for the northwest?

A: (Kelly) I actually don't know of any kit homes that I would say is inherently particularly "green", but I found a good article about how to make kit homes more green: http://www.motherearthnews.com/Green-Home-Building/2003-08-01/Kit-Homes.aspx

Q: What do you think of the semi permanent sprung instant structures sprung.com ? They are made with an aluminum shell, fiberglass insulation and a covering guaranteed to last 30 years. They can be taken down and moved to another location. Do you think they would make a good house?

A: (Kelly) I just took a look at their website, and was a bit disappointed in how little real information they provide. For instance, they talk a lot about their "architectural membrane", but they never indicate just what it is made out of. They say that "Our architectural membranes have pro-rata guarantees of up to 20 years." That is not really very long for something that should last at least a lifetime, in my opinion. But then they are really promoting these as "semi-permanent" structures. The aluminum framework certainly will last a lifetime, and probably longer, so that is a plus.

Q: They are supposedly built to withstand high winds, earthquakes and snow loads. They say they use eco friendly fiberglass insulation and that aluminum is recyclable.

A: (Kelly) Yes, it is true that fiberglass can be made out of recycled glass, and aluminum can be recycled, but they make no comment about recycling the membrane that they admit must be replaced periodically. There are much more benign insulation materials than fiberglass, and aluminum is extremely energy-intensive to manufacture, so on a green scorecard, I doubt this product would score very high.

Q: I'm interested in building a home in Hawaii on the Big Island and already have the plot picked out and purchased. I am operating on a very low budget (max $200,000) and have been pointed by many people towards building a "kit home". I've discovered some great sites that have homes designed for Hawaii, but I am concerned that they aren't as green as I'd like them to be. I'm just barely uncovering what green really means. So my question is, are kit homes green/sustainable? The kits I'm looking at are from www.wbsbuilingmaterials.com and also www.hpmhawaii.com .

A: (Kelly) I looked over the sites that you mention and they appear to offer completely standard buildings as far as materials used and design. The only green aspect that I noticed is that many of the plans offered are rather compact, which is good. Some of the designs could be built using more sustainable, natural materials, but these are not likely to be found as kits. I suggest finding a local contractor familiar with green construction, and work with him to come up with a concept that suits your needs and budget.

Q: We are wanting to find a company that manufactures mobile homes that are built with toxic free materials. We are thinking about wood and fiberglass. A number of us are very allergic to many of the glues, fiberboard, carpets and so many other inexpensive materials. I know many of the horror stories and live with toxic poisoning myself. What suggestions do you have?

A: (Kelly) There seems to be a lot of interest in the topic of green manufactured housing, but not much actually being built, as far as I can tell. Truly green building is easiest built on site from the ground up, using natural, local materials designed to fit together in an energy-efficient design.

Q: Have you researched the biohome on www.biohome.net Seems like a very viable way to build a home sans all the very green home applications (water from air, methane conversion of waste) What is your take on the structure itself?

A (Kelly): I took a  look at the Biohome website, and would say that there are pluses and minuses to their technology. On the plus side is the fact that domes in general are very energy and resource efficient, and with something so well insulated, they should be very easy to keep comfortable in extreme temperatures. On the minus side, I would say that the materials that are used to make them are highly industrial in nature, so there is a lot of embodied energy involved in their manufacture and transportation. Also the polyurethane foam is fairly toxic stuff to manufacture, and if the building were to burn, the off-gassing could be fatal. Another concern I have is that the dome shell would be completely sealed and not breathable, so any toxicity within would be kept there, unless effective ventilation were provided.

Q: I have a 14'x70' mobile home on piers. Both parents are passed on so I want to reduce the size of it to about 30'x 14'...and construct a crawlspace under it of stone, stone wall rocks...(whatever correct material)??? rather than poured concrete. I am in upstate New York and the ground heaves in the very cold winters.

A (Kelly): It should be possible to separate your existing mobile home into a smaller building, but this will take some careful planning and work to accomplish. I suggest that you find a local builder to help conceptualize this. Using stones to build a foundation skirting should be practical, but as you suggest, this wall should have a footer that goes below your frost level.

Q: I have been looking for a manufacture/builder that will supply a (green) package including pre-assembled panels, metal frame and energy efficient quality. It's tough to find the most advanced builders that have mastered the affordable housing market while staying green. If you know of any recommendations please let me know. We would like to build 200-300 homes in the gulf cast counties including multifamily and single family dwellings. I have spoken with some great architects but it seems that the majority of the recommendations are geared towards their profit incentives on referrals.

A: I recently got the communication copied below from John Connell of www.2morrowstudio.com , which indicates that he may well be working on just what you are looking for. 

I've spent the last year studying green, LEED compliant modular houses and we are building two as I speak. They are coming in around $125/sq.ft. including most everything but the land.  This is pretty good for an architect designed custom home in an area where such usually costs upwards of $275/sq.ft.

Q: We live in San Marcos, CA in a mobile home park (land owned) and are trying to repair, maintain it (1975). Interested in non-toxic, affordable home, etc.

A: (Kelly) A mobile home that old has probably already outgassed most the toxicity from its components. You might be able to upgrade it in various ways, through adding to the insulation of the shell, providing some passive solar heating in the winter, adding solar water heaters, etc.

C: American Home Sales, Inc. a provider of quality manufactured homes has announced the unveiling of a new HUD Green Home! American Home Sales is a proud partner of the EPA Energy Star New Homes Program and has made a commitment to building all Energy Star qualified homes. These homes are built to meet the strict standard set by EPA and DOE for energy efficiency and superior performance and are 25 - 40% more energy efficient than the average HUD or conventional home! Our homes also incorporate other "green" features including: water conservation, using and promoting recycled materials, improved indoor air quality, built-in recycling center, trash compactor, solar ready, high efficiency appliances, and more! We have found that there is demand by consumers for a green , energy efficient home. And the cost factor is nominal. Most of our homes average $50-65 sq ft . This home will be the springboard for affordable, healthy green living!

mkd-arc.com Michelle Kaufman Designs offers a variety of green modular, manufactured homes.

Q: What is your idea of a portable house that is strong and well built and in some cases even not small? I have a few I have found I would like to know what you think. Some of them use fiberglass walls and I would like to know if you think that is a good environmental idea?

A: As with most things, there are pros and cons to these sort of homes. Most of them are compact, and that is good. And pre-fab homes often save on labor and materials through careful sizing, etc. On the negative side, most of them are highly industrial, which means that there is a lot of embodied energy, especially if they must be shipped any distance.

I never thought I would like fiberglass, it's just that it's very strong, fire resistant ... won't rot  (and its even waterproof so no mold) and some of those places offer plans that I can assemble  and reassemble it anywhere so that its not only portable but can offer a larger floor plan. I just thought it might last forever and that is good for the environment. I guess I thought fiberglass could be the wave of the future since its long lasting. I would also like a lightweight concrete portable house if I could find one.

It sounds like, given your concerns, that one of the fiberglass kits might be just right for you. Fiberglass boats do last a very long time, and when they start to fray you can put another coat of resin on them to protect them for several more years. Termites and rot are no concern. If they are well designed and manufactured, and tied to a solid foundation, they should withstand most winds. Just check out the fire issues with the manufacture before you buy one... I don't think you will find any lightweight concrete pre-fabs.

Q: I am located in Long Island,New York and am looking to build a Sustainable home in PA. It is very difficult to find builders/contractors who believe in this way of building. I also do "Green " interior design www.healthyltd.com , so I try to educate myself as much as possible. I have Dan Chiras' book The Natural House which is wonderful. Unfortunately, he does not mention anything about Geothermal. I also would like my new home to be LEED certified. I would like to use it as a model for Consulting on Green building. HOWEVER!- This task is not an easy one, especially in PA with the biggest carbon footprint around!  I have finally found an Architect who has designed a Zero Energy Efficient home. ASAPhouse.com website ("About Saving A Planet" by Laszlo Kiss). Would you be so kind to take some time and search his website and give me your professional input and direction on the potential or hazards of this new prefab home.

A: I took a look at the ASAP House, and it has many impressive features; at $650K+, I would hope so! I hope that the per/foot price includes the PV system, since this is a very expensive part. Here are few comments about it:

Even though it is a factory-built modular, it employs rather standard construction techniques and specs. For instance, the framing is wood, and there is no indication that they attempt to use FCS lumber for this, so there is no guarantee that they are not depleting stressed forests to build this. Also, the insulation values they quote are not that impressive, barely coming up to code requirements...I would hope for more here. It puzzles me that they have designed what appears to be a fairly functional passive solar home that could be oriented with either of two sides toward solar south, but they have chosen to orient the plan 90 degrees off, since the PV panels are oriented this way. This means that the passive solar potential of the home is neglected, and in fact the western sun in the afternoon could place a real burden on cooling in the summer. They apparently are relying entirely on solar-electric energy for heating and cooling (through the geo-thermal unit). I question how wise this is, especially in an area noted for long gray winters. Why not use the sun for passive heat, and generate a surplus amount of energy for the rest of the grid? Another factor that could affect interior climate comfort is the use of thermal mass materials on the inside. At the very least, this would reduce the cycling of the heating/air conditioning unit. I see no indication that they employ this principle.

In his more recent book, The Homeowners' Guide to Renewable Energy (which I reviewed for the publisher), Dan does write favorably about both air-source and ground-source heat pumps, saying that the only real disadvantage is the possible air contamination with the refrigerant that they use.

Comment: Cottage in a Day® is a green-minded home-manufacturing company located in northern Michigan. These homes are small, low-impact, energy efficient. The design is flexible, smart and modern. Each Cottage in a Day® home is a cooperative, team-built project in which non-traditional home construction materials are used. All work takes place at a facility in Traverse City, Michigan. After a home is finished there, it's lowered by crane onto a trailer and moved to the home site. These pre-fabricated structures are designed for beauty and longevity. "Pre-fab," however, has come to mean low quality and obsolescence in the consumer's mind, but Cottage in a Day® is redefining the medium. Cottage in a Day® homes are built guided by the philosophy that good design and sustainable use of materials are intrinsic to living well and in harmony. Cottage in a Day® is about creating shelter; but Cottage in a Day® is also a small think tank focused on some basic issues that press at daily life: green living, reducing energy consumption, creating new jobs for the 21st Century. Sarah Bearup-Neal Cottage in a Day® Communications www.cottageinaday.com

Q: I was wondering what you would recommend for an earth friendly home that could be packed up and moved?

A: (Kelly)There are quite a few lovely prefabricated yurt kits now, and some of them are made of solid materials. See my page about yurts.

Q: What do you think about his shelter? www.ubershelter.blogspot.com

A: (Kelly) The Ubershelter concept is interesting, although completely industrial, with all that is implied by that. My first impression was that a good strong wind would quickly set one of these things sailing over the horizon, but then I read some of their engineering data that seemed too indicate that it has been tested up to about 120 mph winds. This evidently is because of anchoring the pedestals to the ground. I don't think I would stay in one during a hurricane to find out if this system might work. Otherwise, it is kind of a neat concept and design layout.

Q: Will a vaulted steel building (25' X 40') with rating of 42 psf hold up under 1-2 ft of earth (US steel. 22 gage with 9 " overlap)?

A: Gauge 22 steel is very thin/weak. So, the answer is most likely No. However, these do require computer analysis. So, no one will be able to give you a definite answer just by inspection.

Q: My husband and I bought a '76 double wide on a basement about 7 years ago before the market went sky high. We see this house is poorly insulated and needs a lot of upgrades to become more energy efficient, but we can't just go buy a new house, as we live on one income. My husband has just completed a certificate in Renewable Energy & Conservation at a local college, and as a result, we've both learned some general things about sustainable living that way. We are interested in either lifting the trailer right up off the foundation and building a better home that way, or possibly earth-bagging around the existing structure. We live in northeastern Alberta; it does get cold here in winter and this summer has been rather hot and humid. We are south facing, so there is potential for possibly using solar on a new roof/building. Could you recommend some sources we could get into that would give us the info we're looking for?

A: If you like the interior of your existing house, then I would recommend that you try to preserve it using better insulation. Surrounding it with insulating earthbags is one option, but this would likely require rebuilding your roof so that it extends well beyond the new earthbag wall, as well as providing an adequate foundation for the earthbags themselves. And, of course there would be many details to work out about how to finish the new exterior around doors and windows.

Another possible upgrade that would not require such radical treatment is something that I have seen recently in my vicinity, and that is to apply a commercial rigid insulation board to the exterior and then stuccoing this to provide a durable and attractive finish. Depending on how thick the new insulation is, this can add a considerable addition to the original insulation package of the home. You might check with local stucco crews to see what is possible.


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