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swiss_chard_fanatic

Earth berm house in Alabama? Tell me why I should or shouldn't.

I have been dreaming about earth bermed home building for about 2 years, but I only just today read that clay soils and humid climates are not ideal (or are perhaps even completely out of the question) for earth bermed houses. I read that dry climates with huge temperature swings are ideal.


You have no idea how disappointed I am after reading that, and I'm just wondering if I need to bury this dream, or if it's still an option. We do get extreme temperatures here throughout the year, with extreme heat in summer but also below freezing temperatures a few times in the winter. We also frequently experience wild (IMO) temperature fluctuations between night and daytime, and within a 12-hour cycle. I am defining "wild" to mean that in the same 12-hour cycle, we will need to run both the heater and the air conditioner. To me, this is nuts. And it creates discomfort and high heating and cooling costs.


We get a lot of humidity as well. I live in southern Alabama. I'm above the water table though. The soil is mostly clay.


I would love to build an above-grade home that had berms on two sides, with the landscaping sloped away from the home on all four sides of the home. But I'm wondering if this is wise considering all the above. Bermed homes are prone to moisture issues, and clay soils are prone to moisture retention and expansion and contraction, which would increase the chances of cracks forming in the concrete, which could lead to water leakage/moisture problems.


So, should I move on and bury this dream? Or are there things I can do in the design to mitigate the humidity and clay soil factors? If I need to move on from this, what can I do instead? I'm not fond of the usual forced air systems, window units, etc because these things will still cost me a lot of money in heating and cooling in this climate. What comfortable / economical alternatives are there for this climate?




Comments (24)

  • PRO
    4 years ago
    last modified: 4 years ago

    First thing is to contact a design professional who is familiar with that type of construction. It would be a lot to handle by yourself if you don't have the experience and construction background.

    I think as long as you are above the water table you should be OK as long as you waterproof the below grade walls. There are several options to accomplish this.....a waterproof mat and drain assembly that is installed adjacent to the wall that allows water to move down the wall to a pipe drain at the footing level. Check out Inka-Drain products.

    There are waterproofing chemicals that can be added to the concrete mix in the truck just before pouring. The old school way was a bituminous coating painted onto the wall, then the full height of the wall protected with a mat. Gravel or pervious rock was then installed adjacent to the full height of the wall/mat assembly.

    Siting of the home on the site will be important as you want to shade in the summer and let sun into the home in the winter. Windows, overhangs, insulation materials, deciduous trees can make a big impact on the cooling/heating loads. There are lots of things to consider. It won't be like building a standard stick frame house on a slab, that's for sure.

    swiss_chard_fanatic thanked Walsh Krowka & Associates, Inc
  • swiss_chard_fanatic thanked beckysharp Reinstate SW Unconditionally
  • 4 years ago
    last modified: 4 years ago

    This would be a cash build, no loan, and it will cost significantly more than a standard stick built house built with better insulation than code required. Do you want a better built and more energy efficient house, or just something outside the norm that has bragging rights for being outside the norm?

    Research siting homes for passive solar. Research double staggered 2x4 walls with a built in thermal break. Research humidity issues with oversized AC and low AC usage. You’ll have a lot more issues dealing with climate control than you think, just because of the humidity. Mold is rampant in berm houses. Most of those houses are self built by people in rural areas, no codes, and with with big equipment in the family, and low dollar amounts to spend.

    They have mildew and mold issues from day 1, because no one waterproofed them properly. Building one properly, costs money. I’ve been in 2 berm houses and 1 cave house. The AR cave house spent a huge amount of money. And it was cool looking. It just always smelled like mildew and had odd drips here and there. Indoor springs do not make for a dry house, even if it’s mostly 60 degrees year round. 60 degrees and 90% humidity is clammy and uncomfortable.

    The TN berm was geodesic dome above and bermed 8’ into the ground on 2/3 of it. It was at least quite light inside, which was a problem with the others. It still smelled like grammas attic with a leak. The 1 in AL “hills” north of Birmingham that I was in must have been modeled on a hobbit house. It might have been a buried Quonset but with dormers. That would have suited his scrounging ways. The “roof” leaked even when it wasn’t raining. No AC, meant mold on the walls. It was just gross. It didn’t help that it had septic issues too.

    Thees no way that I would ever entertain a berm house. Anywhere.

  • 4 years ago

    It may not be impossible, but it is undoubtedly risky. I wouldn't even do adobe out here where it's been done for 100s of years because of the risks (and almost no one will insure it). There are people who specialize in this throughout the country. I'd reach out to them to get a better idea of whether it is realistic in your climate. You could always build a cob structure to experiment with.

    What do you like so much about this style of construction? There are may be alternatives that will work better in your area.

  • 4 years ago
    last modified: 4 years ago

    jslazart, what I like so much is that it would provide a more stable indoor temperature throughout the day and throughout the year in general, and would save on heating on cooling big-time. We spend a lot of money on heating and cooling right now and we feel like it's money being thrown away.

    I'm not looking to do anything overly-radical. I wouldn't consider roof-under-ground in this climate. I was thinking like a normal above-ground house on a slab foundation, with the berms being only on two sides or just on one side (such as the longest side of the structure), and those two sides or one side would be concrete but perhaps the rest of the house would be stick built. I am hoping that a design like that would lower our heating/cooling bills by at least 50%, and provide more stable indoor temps.

    We know a builder who says he's only willing to do stick-built, and he won't even consider doing ICF or concrete or block walls because he says it's more complicated to do the wiring and plumbing and stuff like that, and he says it costs more that way too. I think the issue is that he doesn't have people in his crew who are familiar with working with concrete walls.

  • 4 years ago

    I know it’s not a consideration now, but circumstances change. How salable will that be in the area? Will you ever get your money back? Could you sell it quickly if you need to move? Would you be looking for that one in a hundred buyer or the one in a thousand buyer?

  • 4 years ago

    I have no idea if high thermal mass is the right strategy for energy efficiency in your climate. There's even a lot of debate about whether it's right here in the desert--which has been using it forever. Building a heavily insulated house might be better. If high thermal mass really is desirable, you can make sure there are some high thermal mass elements inside your house that will get a lot of light in the winter (like concrete floors or a brick wall), rather than going full earthship. I question whether just having 1 or 2 concrete walls will really give you the energy savings you are looking for anyway. High R values, a small footprint, passive solar, and the best windows you can afford will probably do more for you.

  • 4 years ago

    The money you would add for a bermed house could go to a solar pv system, insulation and efficient HVAC system. You could cut your energy bill to zero.

  • 4 years ago

    The idea of researching more efficient building techniques is a good one. For example, building a basement may be more energy efficient than building on a slab, or maybe you could build a geothermal heat pump.


    We built a lake house in New England, and it has been very energy efficient. It is small, well insulated and has Marvin wood windows.


    If your current home is average builder grade construction, it probably wasn't spec'd for optimum efficiency. With the right architect and budget, you could build something more efficient, without resorting to a berm home.

  • 4 years ago

    Massive snowfall reported in Alabama last week!



  • 4 years ago
    last modified: 4 years ago

    Yeah if there are other options out there besides berm that could achieve the same results in my climate (more stable indoor temperatures throughout the day and night, and the year as well, plus lowering utility bills) I would be very interested.

    I had initially made the assumption that upgrading the insulation would not be enough, by itself, to achieve those results.

    jslazart, we are already sold on the idea of concrete floors/slab. I hadn't thought about that by itself being a good thermal mass that could help with stabilizing temperatures, but it makes sense.

    Perhaps I should go with the following setup and hope to achieve 50% reduction in utility bills: concrete slab + upgraded insulation + best windows + efficient HVAC + a large deciduous tree.


    Seabornman, Cut my energy bill to zero? At that point wouldn't I have to be producing energy and selling it?

  • 4 years ago

    worthy, yeah for some reason, the few times it gets to freezing, it seems to not want to precipitate, lol. But we deal with some wild swings; I recall recently it seemed that I left for work and had to have the AC on, and then when I got home I turned the heater on. It seems so wasteful to have to do that. Whenever that happens I immediately think "gosh thermal mass would be so nice right now." When you have to run both the heat and the AC in the same 8 to 12 hour period it's just crazy.

  • 4 years ago
    last modified: 4 years ago

    Building America of the US Department of Energy has published scads of detailed research and guidance for energy efficiency homebuilding and retrofits in all US climates.

    For instance, this guide to hot humid climates, such as southern Alabama, shows that just a 40% savings over conventional building can provide a relatively fast payback period.



    Exotic phantasies are best left to the truly dedicated!

    ****


  • 4 years ago

    Our utility company won't buy your excess energy. You just build up credit towards future bills.

  • 4 years ago

    We did 2x6 construction for our shop, and it has probably R-60 in the attic. Exterior foam R-8 sheathing thermal break, and R-21 in the walls. Although we put in PEX to do radiant heated floors, we’ve never hooked it up. 2 1500 watt electric space heaters are enough to keep it warm. We don’t run them at night, or unmonitored. The lowest temperature that it’s ever gotten inside was 50, and that was over an extended period of below 10 degree outside.


    Building energy efficient need not be a mole burrow.

    swiss_chard_fanatic thanked User
  • PRO
    4 years ago
    last modified: 4 years ago

    There are many ways to get energy effiecient homes as for financing it depends on where you live we have friends who did a straw bale house with regular financing . I like thermal envelope homes for many reasons and my favorite part is the amount of windows you can have just not on the north side. I do agree you need to find a company that does earth berm homes to see if it is feasible where you live and of course the money will be needed too. This is the exact same house our friends built 40 YRs ago the design was from Mother Earth magazine it was amazing western Canada was warm all winter and cool in the summer with no mechanical heating or cooling.


  • PRO
    4 years ago

    Some areas of Alabama have such a high clay content in the soil that even conventional building can pose a problem especially the Blackbelt region that stretches west to east across the entire state. This area includes Lowndes, Montgomery and Macon counties. It is the remnant of an ancient prairie and the soil when wet will shift. Areas of the state below that have a much sandier soil that will drink water up. Of course, if you go too far south you might have to contend with a higher water table. Also, the southern half (and much of the rest) have high humidity through much of the year. So, if you have a cooler earthbermed house you might have to install extra air conditioning to keep your home dryer.

    swiss_chard_fanatic thanked Norwood Architects
  • PRO
    4 years ago
    last modified: 4 years ago

    There are a lot of conventional building techniques that will yield a very energy efficient home for less cost than earth bermed. And those would allow a homeowner to obtain a conventional construction mortgage too.

    A backhoe buried school bus tornado shelter was the stuff of childhood nightmares when I’d visit my great aunt. Dark, damp, and with visible rodent tunnels through the glass. The mice lived in the seat cushions too. I’m having a shuddery flashbacks just writing that!

  • 4 years ago

    Definitely look into passive solar, which is more than one large deciduous tree : ) . Those and very good insulation have helped us considerably in Alberta, where the winters are cold and summer are quite warm and getting warmer, and it's getting more humid throughout the year (we can't really say, "but it's a dry cold" any more).

    swiss_chard_fanatic thanked beckysharp Reinstate SW Unconditionally
  • 4 years ago

    I don't understand why a netZero home won't meet your specifications for low energy costs. Don't you have netZero homes in Alabama? We have them in northern Vermont, even with our crazy weather. They mostly use solar, and are super high-efficiency. We even have low income netZero homes, Habitat for Humanity netZero homes, trailer home park netZero homes, and not just expensive palatial numbers.....


    I don't get the "earth" thing. One way these netZero homes are built here is super-thick walls, roofs and flooring. Won't super-thick outer construction and super-efficient heat pumps and a CERV substitute for earth?


    If you really want one one of those homes—regardless of the other options to meet your goals—I suggest re-locating to another state, because in that case your wish is about the house style and not low running costs.

  • PRO
    4 years ago

    Can ;you pay cash or will you need a mortgage? Getting one for a berm house could be a huge impediment. Bankers love to say no. They don't want to get stuck with property they can't resell.

  • 4 years ago

    beckysharp Reinstate SW Unconditionally,


    When you recommended I look up "passive solar," I began digging into the topic, and then from there I looked into passive cooling. Wow! Thanks for that--I've learned a lot but still have tons more questions.


    tangerinedoor,


    I have not yet seen any examples of netZero homes in Alabama, but would love to look into that. Very interesting. But probably a lot harder to do in Alabama compared to Vermont. The problem with thermal mass in the south is--you gotta keep it out of the sun or it'll make the house too hot all the time. And even if you keep the most sun-exposed parts of the home out of the sun via huge trees, reflective coatings, roof overhangs, etc, I believe you'd still need air conditioning.


    Here's an example of a netZero home in Alabama I would not be interested in: uses a lot of energy keeping cool, thus has $50,000 of solar panels on roof to produce all energy needed.

  • 2 years ago

    I live in Central Alabama. I'm considering a Magic Green home. Anyone familiar with a builder that is interested in being trained to build this type of house for me? If so contact me @sw33thomealabama@gmail.

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