I am very interested in the underground housing mentioned in the current article. The drainage doesn't make sense to me though. I can understand the different roofing styles that would keep it from raining in but what takes care of the fact that you've dug a hole and water fills holes. If you have undamaged plastic you can keep the water from entering but what keeps it from seeping into the hole and then leaking around the poly at the seams and accidental tears?

-- Keri Basham (klbash@hotmail.com), November 07, 1999

Answers

Having lived in a owner-built earth sheltered house for the last 20 years my take on the article is that the only down side is the lack of 'finish' to the walls as presented in the article (not the book, which I intend to buy). Water has to come from somewhere to fill a hole. If the water table is so high that the hole fills without rain, you can't put in any kind of basement without pumping a bunch of water. If it is just rain water and surface run-off that are the concern, landscaping to make the water run away from the structure will keep it dry. The only wall leak I have had in my house despite no functional wall waterproofing is immediately below the point in the rain gutter that regularly overflowed. Surface water did actually flood the house before we moved in, overwhelming the sump pump, before I got the landscaping right.

-- kirby johnson (kirby@selco.lib.mn.us), November 09, 1999.

Your concerns are something that I have been wresting with as well. In an existing building your stuck, but in a new building you should build it up on a hill or create a hill with will dirt. This sounds kind of artifical but bear with me. On a hill top you excavate the crown to the point you need to, when your building the foundations and walls you establish a drainage system under and around the walls using course gravel, some sort of pvc netting to keep the gravel from clogging with silt and perferated pipe at the bottom to channel the water down hill and away from your project. You don't have to be very high to accomplish this but you do have to be high enough to give the water a place to go. When you have your walls and roof done you further water proof by adding water barrier products to the surface of the building and joints (I am assuming your building with concrete). Try to cast your roof in as few pieces as possible and then add as much water shedding products as you can. Eventually it will leak. There is no question about that but you can deal with these things at multiple levels. One product which I have found quite useful in shower bases under the tile and grout is a PVC mat that comes in roles much like plastic sheeting. It is considerably heavier, it can be glued in the same manner as pvc with the same products and seems to be quite stable. Of course you will want to run it in courses like shingles but that is another matter. Another thing you might want to consider is a product that is used in moble homes. It consists of a four in thick panel of something like styrofoam that acts as an insulator and on top of that a linoleum-like product that acts as a rain/water barrier. The linoleum is heat sealed at the seams and has a twenty or so sear warantee. Of course in these circumstances that wouldn't apply but it might be a viable option. It would need some sort of protector over the top of it - a few inches of sand may be adequate and then your final soil layer. I hope this helps.

Jak

-- Jak (goodmich@hotmail.com), December 15, 1999.

My downstairs is earth sheltered, eight feet deep, around three sides. I painted two coats of "thorogh seal" onto the concrete and steel filled concrete blocks. Thorogh seal isn't flexible, and if the wall cracks, the thorough seal cracks. To insure no leaks, I put four layers of 6 mil visqueen from the top of the wall down to the bottom of the footings. I also put about six inches of "round rock" (septic system drainfield rock) outside the footings, then covered it with a single layer of visqueen which I perfed with a garden rake. Filter cloth would be better, but I didn't feel like spending the money, for some reason. Under the round rock is 4" perforated pipe, with a positive slope to daylight down hill from the house.

This amount of earth sheltering makes the lower floor of house stay very cool in the summer, and it helps substantially with heating bills, too. I did insulate inside the buried walls with R 21

Someday I'm going to build more completely earth sheltered vacation cabin, down across the road, right next to Jumpoff Joe Creek. It will be buried on all walls except the one facint the creek, and will be covered with enough soil to grow plants on the roof.

I plan to do the roof similar to my existing walls. Concret first, painted with thorough seal,then four layers of visqueen, but then maybe two or three inches of pea gravel. On top of the pea gravel will be filter cloth, then four or five inches of topsoil.

The main reason I'm interested in the earth sheltered roof is because I believe that keeping a growing, green lid on the house will keep the house very cool in our very sunny summer weather. Plus, I like to experiment.

-- jumpoff joe (jumpoff@echoweb.net), January 25, 2000.

The $50.00&UP UNDERGROUND HOUSE BOOK, by Mike Oehler will answer many of your questions. My copy was printed in 1981, check your library.

-- Patti Morris (pmorris@ecenet.com), January 26, 2000.

Ditto. I encourage everyone to get Mike O's book. I found a copy in my library. Anyone with experience with p/s/p, Please contribute! Bob

-- Bob Blessum (robertblessum@netscap.net), February 02, 2001.