Miscellaneous Questions about Natural Materials
Janine Bjornson is a natural builder, practitioner and educator. She began her career in natural building when she trained with The Cob Cottage in 1996. Since then, she has taught over 65 workshops in Canada and the United States, from east to west. Her passion for building with natural materials bloomed out of her love for the earth, in conjunction with her concern for diminishing ecological resources and toxic buildings. As a result of this, Janine has devoted the last 14 years to immersing herself in the world of natural materials and the knowledge of how we can shape dwellings that are healthy, healing, inspiring, and beautiful. She has developed a penchant for natural paints, and plasters and loves the concept of “naturalizing” any kind of home. She loves to share this knowledge with others and this is evident in her enthusiastic teaching style. Janine has assisted in organizing 2 Natural Building Colloquia. She has presented at the Natural Building Colloquium in Bath, New York, Kingston, New Mexico, and Kerrville, Texas. She taught the hands-on natural building component of New College of California’s EcoDwelling program, and Dominican University’s EcoDwelling program. She lives in Sebastopol, California. www.claybonesandstones.com.
Questions and Answers
Q: What are natural materials and what are some examples?
A:
A natural material is any product or physical matter that comes from plants, animals, or the ground. Minerals and the metals that can be extracted from them (without further modification) are also considered to belong into this category. In natural building the natural materials we use most are; clay soils, sand, stone, straw, and wood.
- Organic materials
- Wood ( rattan , bamboo , bark etc)
- Natural fibers ( wool , cotton , flax , hemp , jute , kapok , kenaf , moss , etc.)
- Inorganic materials
- Stone ( flint , granite , obsidian , sandstone , sand , gems , glass , etc.)
- Metal ( copper , bronze , iron , gold , silver , etc.)
- Composites ( clay , porcelain , etc.)
- Other natural materials.
- Soil
Q: What is the difference between green materials and eco-friendly materials?
A: I think that you may find that the answer to your question will vary depending upon whom you ask. However, in my opinion, there is no difference between green materials and eco-friendly materials. I would say they are one in the same. I do care to differentiate between terms like "green" and "natural" though. "Green" may denote a material that is recycled, or is non-toxic. However, this does not mean that it is natural. Decking boards that are made from recycled plastics would be "green" not "natural" These are some basic generalizations that I have shared with you. The classification of each material would have to be rated in regard to various things like:
-location of material vs. location of use
-location of production vs. location of use
-amount of processing
-health
-appropriate use
-toxicity
Q: I am interested in learning more about building with clay but am having trouble finding sources. I run across lots of things about adobe, but nothing so far about clay/loam.. Can you help me with a source?
A: (Kelly) Clay is fine for making very thin coats of color over some plaster, sort like a paint, but is not in and of itself a very good building material. This is because it shrinks considerably as it dries, so that significant cracking can be expected. For this reason clay is best used in conjunction with sand or a sandy loam, which will reduce the cracking potential. The preferred ratio of clay to sand is about 1:2 or 1:3, with the addition of some fiber (like chopped straw) to help bind it all together. Basically this is the composition of adobe, cob and rammed earth. If you have clay soil, then you can add these other materials to it to make something you can build with.
C: I present the "Plenty" firm in the Dnepropetrovsk (Ukraine). We want to establish the production of building materials out of the reed (cane) in the Dnepropetrovsk. There is a great deal of the reed in Dnepropetrovsk region. Reed-plates are an environmentally friendly building material with excellent physical parameters. In the process of preparing reed-plates, the single reeds are pressed between parallel running wire pairs without adding any mineral or chemical bonding agent. The greatest values of reed-plates as a structural agent are the excellent heat insulation and the lightness. The results of professional tests about heat insulation, mechanical solidity and sound-proofing have proved that the reed-plate produced by Hungarian company combines the advantages of several building materials, ensuring its complex use. This product is perfectly suitable for heat insulation of lofts or ceiling and it is the cheapest walling material. We want you to help us find the sponsor (or investor) or advice the ways to establish this production. We have business-plan and ready to present it you. We have specialists in the this area as well. Paul Ignatenko pignATisdDOTdpDOTua
Q: What are the problems and prospect of using locally sourced materials for constructing low cost housing?
A: (Kelly) I am greatly in favor of using locally sourced materials for construction as much as possible, because this eliminates much of the energy and cost of transportation, often does not require further industrial processing, and aesthetically these materials tend to merge well with the environment. The trick is to recognize which materials are available locally that can be used with any particular design, or better yet, to design the housing to utilize what is available. Doing this can considerably reduce the cost of building, since indigenous materials are often rather inexpensive to obtain (such as adobe, stone, cordwood, strawbales, etc.).
Q: I am a product design student at Kingston University in the UK. I am currently doing research for a stool that could be made up of shredded or pulped newspaper or magazines. As a bonding agent for this material I am trying to source a natural tree resin. I have seen this used in a composite form before for coffee cups made of coffee grounds and natural tree resin, but have so far only managed to find it used as a surface finish (for sealing wood). If you know of anything that could point me in the right direction I would be very grateful.
A: Like you, I am aware of the more rudimentary uses and processes regarding tree resins used as a binder. I have not heard or found more detailed information on which resins would be appropriate for a project like the one you described. It seems that one of the most common tree resin used as a binder is pine resin. You may want to try some experiments with this. I would be interested to know where you heard of this coffee cup made from the grounds and bound with tree resin. I wonder if the resin used was from a tropical tree (instead of the more common ones:mastic pine and fir), in that, coffee is grown in that region.
Q: I am looking for a natural/local way to make chinking for log houses.
A: Instead of chinking with a cementatious medium, you may want to try a mud mixture. Cob which is made from clay soil (binder), sand (aggregate for compressive strength) and straw (for a matrix to inhibit cracking, and to provide tensile strength) may prove to be a cheap and easy solution to filling those gaps. You need to create a recipe that works and there may be some tricks to employ to make it attach to the wood. There are several different additives that you could play with to adjust the mix. For example: Need a stickier mix? Add some flour paste (essentially wall paper paste) to aid in the binding and sticking. You can make this yourself and avoid toxic additives
that are sometimes included in the manufactured pastes. Need a stronger mix? Experiment adding lime to the earthen mix to create a more durable mix. However, if there is an air leak as opposed to simple cosmetic filling I would suggest something more insulative. Need more insulation? add perlite, or sawdust. I have heard of some interesting home-made recipes using hemp oil. You may be able to adapt them for your own use. You may also be able to use other oils instead of hemp. The following recipes are from Teresa Berube, California, USA:
Wood and Window Putty
3 cups water
1 cup aloe vera juice
1/2 cup psyllium husks
1 cup Kaolin clay
Mix and add: 6 cups sawdust or hemp hurd powder. Mix with fingers if it gets too thick. Very easy to sand. Shrinks while drying. To make window putty, add hemp oil to make the mixture plastic and waterproof.
Hemp Glue (simple plastic)
2 cups water
1 1/2 cups hemp oil
1 Tblsp psyllium husks
Mix and add:
3 cups Kaolin clay
2 tbsp ground hemp hurds
This recipe is similar to old fashioned linoleum. It can be poured or pressed into molds. When dry it can be cut, drilled, or glued to produce non toxic items of endless possibilities.
Q: I know that caulking, baseboards, paint, joint putty, glue, is pretty toxic, and I know of alternatives for these things, but I was wondering if you knew of any other toxic materials to avoid in a mobile home?
A: (Kelly) If the mobile home is older, most of the VOC's and such will have left, hopefully...otherwise just don't introduce any more by using only natural materials for any retrofitting.
Q: We built a new traditional home five years ago. I became very, very sick and was diagnosed as being chemically sensitive. I have been unable to find a satisfactory home. We want so much to build a "safe" home but the builders in our area do not really understand. I live in OK, about 90 miles north of Dallas, TX where the air quality there is very good. This is a town of about 25,000 and no one there has a clue about this condition. Can you help me?
A: I have been in contact with many people with multiple chemical sensitivities over the years. I have found that each person has a wide range of what they can or cannot be exposed to. The most extreme was a woman that attended a cob building workshop. She was not able to be near anyone in the group. She had to stand 20" away at all times. She found that she could drive a car (it was old and had already off-gased). I believe she was presently living an older trailer as well. There are a few natural building techniques that may be applicable for you. Earthen construction as long as it is pure without additives is a good solution. Of course then, you need to be informed and careful with all the other material interfaces. The roof, countertops and the like.
Q: My concern is over the use of air purifiers inside buildings. I'm an engineering student at the University of Texas at Austin, and I recently took an Indoor Air Quality class, and I was taught that air purifiers release high levels of ozone that when mixed with other agents in the indoor environment, can cause serious health problems. My project now is to incorporate the cost of Indoor Air Quality into the Life Cycle Cost of a Green Building, but as my research continues, I'm finding that IAQ and green buildings don't really work well together. What is your opinion on this?
A: (Kelly) think that the best safeguard for preserving good indoor air quality is to have a breathable envelope for the house, as much as this can be achieved. Modern building methods tend to enclose the indoor space in a hermetically sealed package, which inevitably leads to poor indoor air quality and the necessity to try to mitigate it with mechanical devises like air purifiers. How best to improve air quality in existing homes that trap pollutants? I am no expert in this, but I did post some articles about various filtration or purification methods at airpurificationinfo that might be of interest. There seem to be quite a few approaches to this, and some might be more of a problem with ozone than others.
Q: Are there any health risks/harm from sheetrock dust or sheetrock mud /paint ???
A: The quick answer to your questions is this: Yes, sheetrock products can be harmful to your health. Each product's ingredients vary, however, most of the products carry warning labels that say there may be carcinogens or other ingredients that can cause cancer. The MSDS sheets (Material Safety Data Sheets...www.usg.com) give you a rating of health risk and let you know which ingredients are harmful. Sheetrock, and all Purpose Joint Compound contain Crystalline Silica which can cause lung disease or cancer. Sheetrock also contains fibrous glass and an Ethylene Vinyl Acetate Polymer. These potentially harmful ingredients are found in small amounts in the sheetrock products, please review the MSDS sheets to see the percentages. The most important thing to know when handling these materials is that the dry fine particles can enter your body when sanding, cutting and the like. You want to make sure that you are wearing a fine particle dust mask or respirator. The MSDS sheet confirms this. I would like to add that any dry airborne fine particles, even if they are natural and organic can cause lung disease with long term exposure. I recommend purchasing a respirator with the appropriate canisters for use with any fine particles......joint compound, sand, clay, straw etc.
Q: My neighbors are building a tool shed under a tree in the community garden right under my bedroom window. I have allergies, both to mold and to formaldehyde. On your website is mentioned OSBs that are mold/rot and formaldehyde free. OSBs are being used for this shed. The plan, I am told, is to 'stain' the shed to prevent further off-gasing. I was also told that the OSBs that are being used are recommended by your organization. The gardeners did not say their 'wood' was formaldehyde free, and even said trees contain formaldehyde. I'm afraid I'm getting a run around. I've already had a problem with mold in this particular corner of their garden from molding wood chips. I fear future mold problems with the OSBs they are using. Can you enlighten me here? What would you recommend?
A: (Kelly) There are low- and no-formaldehyde OSBs available on the market, but you will very likely have to have ask your local lumber supply outlet to special order them. It does sound like you are getting a bit of a run-around by your neighbors; greenhomebuilding.com has not recommended any particular OSB products, and I have certainly not heard of trees producing formaldehyde. Many fibrous materials, including OSB, can harbor molds if they stay moist and warm enough for a period of time. The best way to avoid this is to keep such material absolutely dry...so at least try to make sure the shed they are building has a good roof and foundation!
Q: I noticed on your Q & A page mention of using gloves, etc. to protect oneself from lime burns. Yesterday I was helping a friend build walls with a mix of soil, sand, concrete and lime. Even though I was using rubber gloves, I did get some burns on my knuckles and near the cuff of one glove. Do you have any suggestions for healing these burns? They're smallish second-degree burns. I checked a couple first aid websites, but didn't see much info. about chemical burns. I thought you might have some info particular to lime burns. I was a little concerned that the burns took on the same color as the mix I was using (is it possible that something is trapped inside my skin?). I applied a calendula ointment once... not sure if it helped.
A: I am sorry to hear about your burns. It sounds like the mixture you used seeped into, or through your gloves with water. I have had this happen many times. I am not that sensitive, therefore, I have never been burned. In addition, I always make sure that I rinse my skin with Vinegar at the end of a day (or even during if I have come into contact with the lime) to neutralize the alkaline lime.
I have irritated my palms once quite badly. The skin shrunk, tightened, dried and peeled. I did not have burns though.
I want to address a couple of points regarding the burns. It is likely the lime burned you, but all of those ingredients can irritate the skin. Cement may also irritate sensitive skin, and certain pigments can be toxic even if they are natural.
Either way, it seems you have burns. I am not a trained medical person, but I can tell you what I use for burns. First, I use prevention (as above). Secondly, I tend to go the more natural route in the world of remedies. I have a "Scar & Burn" healing oil that I have found to be really effective. It is made by SIMPLERS Botanical Company, in Sebastopol, CA www.simplers.com You may be able to buy it at your local health food store. The ingredients are; Helichrysum, Mugwort, Sage, and Lavender angustifolia essential oils in a base of Calophyllum oil, Rose Hip Seed oil, and Calendula infused in Olive oil. Excellent quality lavender is notorious for healing burns on it's own.
What colour was the mix you were using that transferred itself to your hands? My sense (based on my experience) that the pigment has probably stained your skin (if you used pigment in the mix). This happens easily if it is a bright pigment and you work with it and it contacts your skin. It probably doesn't have anything to do with the burns. Although, it happens to have stained the skin that has become burned. Normally, the pigment would wash out of your skin after some time. However, this may not happen as normal if you are not washing, scrubbing and using
your hands due to the burns.
If you are concerned about the discoloration due to the pigment, I would suggest you find out what kind of pigment you were using and see if there is anything toxic in the pigment. It is likely that you were using some non-toxic earth pigment as you need to use specific pigments that are lime compatible and will not bleach out when in contact with the alkaline lime. However, we all know the saying "better safe than sorry".
I need to mention that Lavender Oil should not be applied full strength. Pure essential oils should be used on the skin in a diluted form as in the Scar and Burn remedy listed above. For example, if the burn is fresh and you need to cool the tissue down, place 4-5 drops of Lavender Oil in a bowl of water that has ice in it to keep it cool. Immerse your burn in that diluted mixture to cool the tissue. These are directions I have been given from local herbalists. If burns are severe you should see a physician of course.
Q: About tire bales, I can only wonder, how safe they are in the long term. Surely, stucco will cover them up and perhaps that is enough. Do you have any information on that?
A (Kelly): This is a controversial issue regarding the tires, especially the bales which are so densely packed; I personally would shy away from them, if I had the chance to use the earthbag method. Bags can be filled with utterly natural materials, and the polypropylene does not outgass as far as I know...and they do get buried in some sort of plaster. Sorry I can't be more scientific in my answer.
Q: I am searching for information about plastic water piping for residential use. We have to replace the pipes in our home and we are looking for the pipes that will cause the least environmental damage both during creation and continued use. I am particularly looking for information regarding leaching of organic toxins into the water. I am somewhat suspicious of plastics after learning about PVC leaching phthalates. I am considering PEX-cross linked polyethylene or XPA-durable raised temperature polyethylene. Are either for these safe? Is copper a better solution?
A (Kelly): I wish I had a definitive answer for you about the safest water pipe to use, but I don't. PVC is known to have toxic effects during its manufacture, and I have heard of chemically sensitive people avoiding its use as water pipe. Copper has been shown to have negative health effects as well, with some possible leaching of the cooper over time. I have heard good things about PEX tubing, but this anecdotal. It sounds like you have studied the field more than I, so perhaps you can inform me about the choice that you make and why.
Q: Years ago I visited some people whose shower stall was entirely made of wood. Would you be able to tell me the right kind of wood that could be used for a shower stall? I am concerned about how to clean it also...I LOVE the shower stall with the rock.
A (Kelly): The wood I used in my shower stall was of two varieties: redwood and fir. I chose the redwood because it is naturally rot-resistant and I happened upon some bits of recycled lap siding that I could use. Cedar would also be a good choice for the same reason. The fir was a 2X6 T&G flooring material that I used for structural reason in that portion of the shower stall. I coated both of these woods with several coats of polyurethane and then calked the T&G with silicone caulk. After about 5 years, I re-sealed the wood with another coat of polyurethane to renew the finish. The important thing is to seal the wood from getting damp.
Q: I don't see any mention of hemp as a building material. I am sure you must have come across it in your line of work. In what areas have you seen it most effectively used?
A: Believe it or not, I have not come across it in my line of work. I work in the west of North America primarily. The use of hemp in building is virtually non-existent in the Unites States as the growing of hemp is illegal. Although Canada grows hemp, most of the production is used for food and clothing. People in natural building have used hemp rope, but I have not been exposed to any inventive (and practical) uses like they do in France. Most of the innovative use of hemp in building is being done in France.
Q: I am a student of interior designing studying my thesis on eco-friendly interiors. I have delimited my study to recycled and natural materials. Can the study be further delimited to only natural materials or only recycled & recyclable materials? If yes,how and what all criteria should be considered with respect to sustainability? Should I also study the manufacturing processes or just study the properties? I am a bit confused.
A:
I understand why you have some confusion on this topic. There are many layers to what we may refer to as 'eco-friendly'. You will find that products that are labeled eco-friendly are labeled this way for a myriad of different reasons. This depends on the producer or advertiser. I would suggest determining your personal definition for this term (after your research begins), to assist you in deciding what will apply to your thesis.
It is really up to you to determine how to narrow your thesis. However, in my opinion you must not exclude 'natural materials' if you are looking at eco-friendly interiors. Natural materials can include materials that are minimally processed and untreated, thus, making them one of the most healthy and friendly materials to use and be in contact with. I regularly make my own paint from clays, sands and pigments, or even milk. You would not want to exclude such simple healthy options.
Many recycled products may be considered eco-friendly because they used materials that would have otherwise ended up in a landfill, however, this does not mean they are natural or healthy.
I would definitely consider studying the manufacturing process of materials. This is critical to understanding the whole picture. If a recycled product is being produced by a factory that dumps toxic effluents into a river and is causing the the local flora and fauna to die, is this eco-friendly now? Good food for thought.
I would highly recommend reading McDonough and Braungart's 'Cradle to Cradle, remaking the way we make things'. It is an excellent book. Another old favorite is 'Ecological Design' by Van Der Ryn and Cowan. You may also want to see the film 'Blue Vinyl' about the vinyl industry.
Sustainability is a holistic vantage point. It involves digging deeply into ecological balance. Many believe that we are currently too late for 'sustainability' to make a difference and that we need to be moving toward restorative and regenerative processes. Because there are many different levels to something we may call eco-friendly or sustainable, I will list some categories for you to consider. All of these categories affect the ecology of our planet. Ideally we would be considering all of these points when striving for health, and sustainability. You will notice during research that people and companies refer to products and such as eco-friendly when only one or more of these points are touched upon.
Health effects on: -person using product -people producing product -people installing the product -animals used in testing the product
Health effects on: -The Earth and it's non-human inhabitants -animals, birds, insects, microbes, fungi, plants, etc., -ecosystem balance to sustain and maintain life
Embodied energy in product. The embodied energy of a product is all the energy that is used to:
-extract the materials used in the product (mining, logging etc.,) -make the product (energy used at the factory etc.,) -ship the product (including the truck, the fuel etc.,) -install the product
Operating costs. The operating cost of a system or a material is the cost that is calculated over the life span of the product. -maintenance of product -energy consumed for operation (such as ventilation system, or PV system)
Life cycle of the product. Although a product may be safe and inert for us to use within it's life cycle, what happens to it after we are finished with it? Will it pose an ecological threat at the end of it's use if it ends up in a land fill?
Company ethics. Companies and their operations can also be considered in regard to human ecology and sustainability. -living wages for employees -healthy vital surroundings for workers -health care -sustainable work hours -Certifications (Fair Trade, FSC certified wood products, Cradle to Cradle, Organic. etc.,)
I hope this assists you with your thesis. It sounds like a fun and stimulating topic.
Q: I'm trying to compile a list of the eco-friendliness of popular home building materials, from brick, concrete, wood, and glass to bamboo, rock/stone, adobe, etc. Is there a standard list from least environmentally friendly to most environmentally friendly?
A: There isn't really one standard list of criteria. Wikipedia says it succinctly, "Environmentally friendly, eco-friendly, and nature friendly are synonyms used to refer to goods and services considered to inflict minimal harm on the environment. Because there is no international standard for this concept, the International Standards Organization considers such a label too vague to be meaningful."
Q:
As a safety engineer I have heard that a metal roof attracts electro-magnetic energy that is harmful to the human biofield. Do you have an input on this?
A: (Kelly) I don't have any information about roofs specifically, but I do know that many people report sensitivities to metal parts of buildings. I think this is a very personal thing. More people seem to be affected by the EMF's emitted by electrical current in house wiring and efforts are often made to route these wires away from places where people sleep or spend much time...
Q: I would like to build a workshop in my garden using natural materials. I need to house an electric front-loading ceramics kiln, and whilst there are guidelines relating to clearance around kilns housed in combustible buildings, I'm also concerned about the drying effects of occasional firings on the structure of the building. I don't want to have to resort to manufactured fire-proof boards to shield walls and ceilings. Any suggestions would be very very welcome! I live in South Wales, UK.
A:
It seems to me that one of the best options for your building is a vernacular building method from your area. Cob construction may just be the thing you are looking for! I am not familiar with the specs required for clearance for your kiln and I am sure it would be wise to follow these specs regardless of the type of building that you are going to build. However, a cob wall covered with a well tested and well applied coat of earth plaster (ideally the same clay soil used in the wall so the expansion and contraction would be similar) will be much more stable and of course fireproof comparative to a stick frame building. Make sure you do not use straw in the plaster.
In conventional buildings sheetrock is used as a wall surface, but also for fire resistance. Sheetrock is made form Gypsum (calcium sulphate). This may also be a good plaster option for your wall but I cannot say how it may perform on top of an earth wall subjected to the temperature swings from your kiln. You may want to consult your local Gypsum product professionals on this matter. In the United States we have US Gypsum and the Gypsum Association (maybe you have something similar).
I would recommend doing some test panels and placing them near your kiln to see how they perform.
The only other obvious option may be to build a stone building if stone is one of your local resources.
In regard to the roof/ceiling, it seems that you may need to rely on normal safety procedures in regard to materials due to fire hazard. Most roofs in your type of climate are framed with wood and rely on sheathings that are combustible. Unless you have an unlimited budget and can afford to build using steel beams etc., with a slate roof you may need to consider the normal safety precautions.
Q: I would like to know if you can tell me about some extra unconventional usage of white cement. I would also like to know how to have some green control over the manufacturing and usage of white cement as a building material.
A: (Kelly) White cement is a specialty cement for applications that require a high degree of whiteness, usually for aesthetic reasons. Like any other cement product, it is not very green, in that its manufacture requires a great deal of energy input and releases CO2. In some applications you might be able to replace white cement with lime, as with a plaster or stucco. While manufacturing lime does emit CO2, it reabsorbs it as it cures, so it would be considered a greener material.
Q: Could you please give an example of an indoor climate that you have experienced that you feel is unhealthy. -Identify three different Principles that are not considered in this indoor climate; -Explain possible effects each of these could have on the occupants; - Explain how you could improve each of these.
A: (Kelly) Many modern building materials and home furnishings will off-gas toxic fumes for quite some time. I have walked into some new buildings where I have recoiled from this effect, which can be hazardous to one's health. Some people are more sensitive to this than others. The best practice is to use natural, non-toxic materials in the first place, but if that is not possible then the next best thing is to allow the space to breathe with the windows open for as long as it takes to eliminate the fumes. I think that this is sometimes called a "sick building syndrome" and it can lead to head aches, nausea, impaired brain function, etc.
Q: We have built an adobe pizza oven. We live on the north island of New Zealand and need to make it weatherproof in some way. Having read some of your Q&A I understand that cement or linseed oil are not suitable for ovens. Is it possible to use a waterglass coating to seal it somewhat against wet weather?
A: Water glass is unlikely to be able to keep moisture out completely. The best thing to do for ovens, is to build a roof over them, or to cover them when it is raining. Here is a quote from Kiko Denzer, author of "Build your own earth oven" on the topic of sealing ovens using oil (which is the most common material people think of using). The following quote also describes my thoughts on how waterglass will likely perform.
"I don't recommend oil as a roofing substitute. Oiled plaster will limit how much water absorbs and improve the mud's ability to withstand degradation due to moisture, BUT it won't keep water out. If the oven is wet, it will take inordinate amounts of time and fuel to heat up because you'll have to drive out all the water (converting water to vapor takes way more energy (orders of magnitude) than just heating it up from 211 to 212). It just doesn't make sense to me to skip the roof. However, if you don't want to build an entire structure, you can just cover the oven with a lightweight bit of metal sheet or tarp when you're not using it (either way, leave a gap between the oven and the cover, otherwise you'll get moisture from condensation -- which can be significant)."
Q: I am from north of Morocco and developing an educational project based on the Permaculture Principals. One of my goals is the revaluation of the natural building systems, since this is almost vanished from the memories of the farmers. I have already achieved the building of a small studio, together with two farmers/traditional builders. I have used stones and clay, straw and lime as mortar. At this moment I am building a dry toilet/ bathroom. And my idea is also to include a shower, as well as a lavabo and bidet. these will have their own drainage system leading to a natural depuration for grey water. My problem is I can 't find clear guides or information on how to seal the wall and to make them water resistant. Could you please help me with some ideas?
A: There may be many ways could brainstorm trying to figure out how to seal a shower etc, but you are in Morocco and it is Morocco that we look to from North America in this regard. I would suggest to take full advantage of the local Tadelakt treatment for showers, sinks and the traditional Hammams. Many people in Morocco are still doing this (I traveled to Morocco and saw it myself) and there are many workshops offered to train people. Thank goodness this tradition has not been lost.
