Close-up view of water damaged plaster

Close-up view of water damaged plaster


“This is the dome of a friend in Colombia, is located at 1,600 meters above sea level on a rainy climate, in a land with many gravel. The superadobe is stabilized with hydraulic lime, has a double wall to 3.30 and wire. Foundation is 60 centimeters deep and filled with cement and stone above it a concrete plate 6 cm. The iladas of superadobe may have moisturized longer than necessary due to rain during the construction process despite being covered with plastic dome. It has lime plastering the outside that have not worked. Feels much moisture inside and you see many cracks inside and blown, cracked plaster outside. Apart from a “diagnosis” purely visual, but we seek what to do to help the owner to learn how to waterproof the outside and inside.”

Kelly: “I feel so sad when I see something like this. The dome house is really quite beautiful and it is such a shame that it has these major problems. Owen and I don’t advise people to build earthbag domes in wet climates for this very reason. Short of building a separate roof over the structure, it is next to impossible to guarantee that moisture won’t find its way through the plaster to the inside and cause the sorts of problems encountered with this dome.

The person who posted the images on Facebook is mostly focusing on failures due to fundamental stresses within the design, but I think the main problem is the lack of having a waterproof skin, which allows all of these other problems to occur.

My recommendation to save the building is to make a permanent separate roof over the entire structure, with eaves to keep the rain off the lower parts of the walls as well. There is a diagram of one such roof shown at the beginning of this project. First build the roof, then wait until the entire structure has a chance to dry out completely, then repair and replaster the walls where necessary.

I hope they can save the building; so much work and love into building it obviously.

Muy buena suerte con todo!”

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Comments

Don’t Build Domes in Wet Climates Without Roofs — 22 Comments

  1. Dear Owen

    I send this picture to Kelly explain exactly what happen on this dome, the owner is a close friend, Nohra. The main problem is not the rain, it was that the walls were to humid the earth inside them and then the rain because a plaster were made with lime didnt protect enough the dome.

    Here you can see a picture of how we repair this dome fater let it dry almost a year :

    https://www.facebook.com/media/set/?set=a.783493581708278.1073741896.100001429309035&type=1&l=512fa2990e

    Of course you can build a dome in wet climates, you just need to stabilize better the earth with a better selection (more sandy ) and covering with a cement fortified plaster for exterior.

    • Great job. It turned out beautiful. This would make a good blog post, okay? Maybe you could answer reader’s questions and explain more when I publish the story.

      • Of course you can use these pictures to give more information about this dome en Cachipay (Cundinamarca – Colombia)

        It still a lot of peoplo doing domes as they were born: in the desert or dry weather, so they still traying to use a lot of clay and natural finishes.

        But building with some coherency and common sense can help to build safe and secure: stabilized with cement one more sandy soil, doing better foundations (ciclopeo) and using cement plaster (this cement is added diluted asphalt emulsion which improves its resistance, waterproofing and elasticity)

        Of course and thanks for the invitation to answer questions once you publish more pictures about this restauration.

        Always a pleasure to read your blog and share practical information , the only way to improve !

  2. Owen suggested using something to me to use that “IF” it can be purchased and utilized in this or other like locations would be an excellent choice. That’s a pool liner. I’m going to use it and I think for my build at least, will do wonders. I loved the idea for my place. I can hope that it is available there and is in their price range. In my build, it’s a great idea and makes so much sense. I believe that it would work there and really get great results with a good roof overhang and NO loss of the roof OR WALLS.

  3. Another great way to avoid the analysis paralysis, after building a shed or other small structure, is to build in stages.

    If there is a portion of the plan that one is confident of the design, build just that section, or just even one room. Once that portion is completed, and you have learned more about how it all comes together, one can add on and build more.

    Sometimes when people find themselves planning for several years, the project just seems so large and overwhelming. It’s difficult to get started.

    That’s the perfect time to break the project up into smaller sub-projects.

    Get something done.

    Even if you make a few mistakes, it’s worth it. The satisfaction of actually getting something up, even if it is small, is very exciting and empowering. The insights gained from completing a small portion of the overall project also makes it a LOT easier to finalize the design details of the rest of the plan that may have stagnated before.

    Just find or create bite sized chunks that you can manage. Do one of them, and move on to the next. Patience and Determination will then become your biggest virtues.

    Nothing like some good muscle aches and sweat to lubricate the brain either.

    • That’s a good approach. Even rich people around here build in stages to minimize need to borrow money. It makes sense in so many ways as you mention, not just to save interest to the bank. It’s very hard to envision every detail of the project when it’s just drawings. Ideas and improvements will come to you as you build. Be open to suggestions and new ideas that come to mind and the end result can be a much improved design.

  4. Planning is important, but it’s also important to avoid “Paralysis by Analysis.”

    As with most things in Nature, there is an equilibrium to be reached between planning, and obsessing over details.

    Here is yet one more excellent reason to BUILD A SHED FIRST.

    When someone finds themselves planning for several years, I suggest that they set those plans aside and build a small structure, using the same techniques they hope to use on the building they have been planning for so long.

    It’s a great way to break the inertia, but also a great way to learn. You’ll probably learn the details you need to break your analysis paralysis.

    Eventually you’ll need to take the big leap and give it a try. Accept that you’ll make some mistakes. Accept that you’ll need to adjust your plan accordingly. Accept that even the best laid plans are imperfect.

    Balance.

    It’s not just for high-wire acts. It’s for everyone.

    Planning is very important. Take your time and do your best.

    The intersection of Planning and Courage is where things get done, and done well.

    Use both.

    • I agree. In Zafra’s case though they’re developing an innovative design for earthquake resistance. We’ve had extensive email discussions over this. It would be good if they did a shed first to test out the system.

  5. I guess what you said about doing the research first and, that building a home is a serious endeavor really does apply here. It looks good on a blog site but, it also can have a down side on a blog site. Both of those examples have been displayed here. Myself, I see this as a plus for me because it’s a true teaching of what NOT to do and, a definite what TO do.

    • Water is the number one enemy of buildings. Fire is a close second. I couldn’t fathom building a structure without a good roof or rainscreen anywhere except a desert.

    • It’s far better to spend 3 years planning than have to make major repairs or even lose the biggest investment of a lifetime.

  6. This is happening a lot in South America, I’m afraid. We know some people here in Venezuela who built themselves a dome. I just kept shakin my head – that thing is going to leak sooner or later, just wait…
    Owen did you or Kelly actually give the poster of those photos your advice somehow? I don’t see comments about needing a roof there and I think it’s badly needed info for those people!

    • Yes we replied to them. That’s Kelly’s email.

      This is a serious issue. If 2-3 people have failed earthbag domes then that could completely stop earthbag building in that area. The lesson here is to do adequate research. Building a home is a big job. It’s not something you just do on a whim after reading about it for a while.

  7. Thanks for posting this. It’s very informative and definitely a thing we all must remember when building. Making the right decisions before the build is better than the consequences if things aren’t considered. I see this as nothing but a “positive plus help” Thanks very much again………..

  8. Owen, you make an outstanding point about the key feature of a rainscreen. If water penetrates the outermost primary weather proof cladding, the inner secondary layer is there to protect the building. The water can still just drain down the wall and out the lower screened opening at the bottom of the wall.

    I even encourage taking advantage of this feature as a out cladding leak detection system.

    Imagine installing a very small gutter system at the bottom of the wall underneath the lower rainscreen airgap. Then pitch that small gutter to a single collection point. Perhaps a glass jar.

    That glass jar will collect all the water that runs down the wall inside the rainscreen airgap. As long as the outer cladding is doing its job well, the jar will remain empty. However, if you ever find water inside that jar after a rain, you know you have a leak in the outer cladding, and it is time to perform maintenance and repairs before the inner plaster and dome become damaged.

  9. Owen’s and Kelly’s advice is on target.

    There is another alternative to a standard roof over a dome.

    Rainscreen.

    As the dome is constructed, leave loops of twine between each layer of bags, looped around the bag on the inside of the dome, and looped back outside the dome on top of the next layer. Let the ends run long to the outside of the structure, say a foot or so. Do NOT embed these twines into plaster layers. Plaster around them.

    Apply a secondary protection layer of plaster. Earthen plaster is sufficient for this layer. Smooth it out. A limewash over that earthen plaster wouldn’t hurt to help waterproof it, but is not mandatory.

    Make furring strips out of saplings, pallet wood, bamboo, or whatever you can find locally for free or very cheap.

    Attach the furring strips to the exterior dome wall by tying then on using the twines looped around the bags as the bags were laid.

    If attempting a retrofitting of a rainscreen on an already existing dome, Try using a “bale needle drill bit.” This is a strong shaft of steel with a sharp cutting point with a hole like a sewing needle in the end. Use a drill to drill the steel shaft through the bag wall, from outside to inside. Have a helper thread the needle with twine, and then pull the needle out pulling the twine through the wall with it.

    Note: The twines need to be installed in vertical alignment so that the furring strips can run vertically up the walls, and curving up over the dome.

    Once the furring strips are installed securely, install sapling, pallet wood, or bamboo strapping across the furring strips.

    Then attach wall cladding of your choice over the strapping.

    Wall cladding options are numerous. Choices include, but are NOT limited to the following:
    Plasters/Stuccos of various types
    Shingles
    Clapboards
    Board and batten
    Fired Clay tiles
    Ferrocement
    even Thatching is a possibility.

    It is best to think of the top of the dome as a FLAT roof and use a membrane for the uppermost areas that don’t have much slope. Then you can cover that membrane with other materials as you deem appropriate. This flatish top can even be a living roof.

    There is even the possibility of mixing and matching multiple types of cladding for practical as well as artistic effects.

    Perhaps a living roof on the top of the dome and lime plaster for the more vertical walls?

    Let your imagination go wild.

    The very top of the dome should have a cupola to vent the air gap of the rain screen, and the very bottom edge of the dome should have a screened air gap for air intake.

    With a reasonable amount of ingenuity and effort, a rainscreened dome should be just as water tight, or perhaps even more watertight as a roofed dome. It also can be cheaper, depending upon what materials are used and how they are acquired and installed.

    In many ways, a rainscreen is a roof. It’s just a curving form fitting roof that’s just an inch or so away from the dome wall everywhere that need not require any expensive roof structure or roofing panels.

    Keep in mind that the plaster secondary barrier if it is a plaster layer need not be completely dry before the furring strips are attached. It only needs be firm enough to support the strips and workers climbing up attaching the primary drainage cladding.

    Rainscreens have been around for centuries. There are STILL the Rolls Royce of building protection systems. Nothing has been found that is a better option. It is sad that they don’t get enough consideration in the Natural Building community.

    Don’t get turned off by commercial sales pitches for rainscreen products on the internet.

    There is no reason why a rainscreen cannot be built out of salvaged, cheap, and/or Natural materials.

    Don’t be afraid of learning more about how rainscreens work from the expensive products out there, but once you understand how the concept works, it’s easy to build a rainscreen out of materials of your choice. The method I described above is just ONE way to do it. Once you understand how a rainscreen works, feel free to come up with your own system.

    Rainscreens can be applied to any structure, not just domes or commercial buildings.

    Check them out.

    In my humble opinion, this is the smartest option in any rainy climate. Regardless of architectural style.

    • Thanks, Jay. This topic needs to be emphasized more. Dome builders will probably be more inclined to use this method rather than a regular roof because they won’t lose the beautiful dome shape. In fact, it will be virtually undetectable. Like you say it doesn’t have to cost much extra money. Rainscreens also provide an added buffer against overheating. And any water that finds it’s way through the rainscreen will quickly drain out the bottom and/or evaporate out the top. Cupolas are great for passively venting your structure.

      Who wants to see a detail drawing of this?

  10. Here’s another dome with failed plaster.
    http://www.naturalbuildingblog.com/a-sad-but-educational-footnote/

    Some would say we shouldn’t post these images because it might give earthbag building a bad image. But it’s important to warn people and know how to build correctly so this sort of thing doesn’t happen. Every type of building has it’s pros and cons, and we’re confident that earthbag structures compare very favorably to other building methods.

    Structures built with other building methods might be destroyed once the plaster fails. Actually, these folks could build a roof, peel off the failed plaster, allow ample drying time, apply new plaster and they should be fine. Welcome to the school of hard knocks.

  11. this is why a roof has always been part of our plan even then our design has changed like 6 times. I also hope once they get a roof up they can save the structure.

  12. What a shame. It’s such a nice building. But the main reason I published this is because this problem is not uncommon. Domes evolved in deserts. It’s very risky building unroofed domes in rainy climates.

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