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Tan
Joined: 23 Jul 2007
Posts: 1
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 Posted: Tue Jul 24, 2007 6:34 am Post subject: walkout on a flat lot |
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I am asking experts' opinion on building a walout basement on a flat lot. I bought a flat lot of 1.8 acre with the footing of 110' to 120'. The builder told me that it is possible to build a walkout basement by backfill the front yard (they have a lot of dirt on the lot for this purpose from a pond digging in the community). The questions are:
1. Is this doable? How common is this technique to build a walkout basement on a flat lot?
2. They did not do any dig on the lot for footing foundation, and they said that the footing foundation will be built on the grade level and then back fill. Is it safe for the house?
I feel puzzled on Question 1 and terrified on Question 2.
Thanks. |
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phansford
Joined: 18 Apr 2004
Posts: 500
Location: SW Ohio
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| Posted: Thu Jul 26, 2007 5:56 am Post subject: |
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Tan,
I am not a fan of trying to force a walk-out on a flat lot. And I wouldn't let the contractor just place the footings at the present grade without removing topsoils and consulting a structural engineer (easy quick phone call)
But we just had this conversation recently .... maybe it might hold some answers for you.
Good luck. |
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JWmHarmon
Joined: 15 Apr 2004
Posts: 109
Location: Ohio
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| Posted: Thu Jul 26, 2007 6:33 am Post subject: Earth berm house |
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Your builder is talking about an earth bermed house design. There is really no difference between a traditional dug basement house and an earth bermed house except for the fact that with the earth berm you don't have to dig out the earth first.
When digging a basement some of the earth that is removed is used to backfill around the foundation. The rest is either spread around the lot or trucked away. The footer for the foundation is built on virgin earth or on properly compacted fill below the frost line.
With an earth bermed house there is no need for excavation other than to assure that the footing is on virgin earth or properly compacted fill. Earth is then used to surround as much of the foundation as desired creating a berm around the house. This berm can be a few inches or a few feet high or may extend up to nearly the top of the foundation. If this berm is extended over a properly constructed roof then the house is called an earth sheltered house. The berm must be high enough to protect from frost heave of the footers.
Earth bermed houses are as old as the hills, though not common in housing developments. You may have read in your history book about the sod houses on the American plains in the 1800's. You can find examples of earth berm and earth sheltered house in Iceland among other places.
There was a lot of interest in earth bermed houses during the "energy crisis" days of the 1970's in the U.S.A.
This web site shows a house that uses earth berming with a walkout lower level on a hillside lot. The same principle could be used on a flat lot. Scroll down to the last picture. http://www.marcoplosconstruction.com/Projects%20&%20Photos.html
Sometimes tubing is placed on the ground before the berm is built up. These tubes could be used in conjunction with a heat pump to take advantage of the constant 55 degree temperature of the earth several feet below grade. The tubes could also be used to provide fresh air year round. http://www.earthshelters.com/Other_const.html
An earth bermed house requires special attention to drainage and waterproofing details. This is no more or less important in a dug basement house or in a bermed house.
Frank Lloyd Wright designed earth berm houses for workers near Detroit, Michigan around 1940. These were to be made of rammed earth and to be sheltered by earth berms. See the third picture down at this site. http://www.eartharchitecture.org/
Wright also designed the Herbert and Katherine Jacobs House II also called the Solar Hemicycle House. At this site you can see the earth berm wrapping around the right side of the house. The earth berm in back was constructed from the earth taken from the front of the house. http://www.news.wisc.edu/11192
Here is a site that gives details of the heating and cooling systems and the advantages of the earth sheltering berm at the Jacobs house.
http://digicoll.library.wisc.edu/cgi-bin/WI/WI-idx?type=HTML&rgn=DIV1&byte=1581194
We recently constructed a three Habitat for Humanity houses on hillsides. The basements had to be built into the hillside. One of them required extensive fill in front of the house. The lower side of each house was built on grade level and had to have a berm built up to give the required depth for frost protection of the footer. We were fortunate to have the necessary fill donated.
Earth berm houses can be built with sloping berms or terraced berms. Terraced berms can have sloped transitions from one level to the next or can have walled terraces of stone or brick with flower gardens or lawn areas.
_________________
When building or manufacturing always ask, "How will we recycle that?" - JWmHarmon |
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phansford
Joined: 18 Apr 2004
Posts: 500
Location: SW Ohio
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| Posted: Wed Aug 01, 2007 4:50 am Post subject: |
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JW - Good information, but I'm not sure the original poster wwould think a berm house would solve his problem. The issue typically is one of style. There are too many "Colonial" berm houses  |
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