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emmachas_gw

desperate for advice on partial basement

I'm having no luck at getting advice on a partial basement in my south Louisiana area. Any help would be appreciated. We are building on a lot that has a natural slope of 10 ft.

The natural fall of the lot from the front to the back of the house will be about 5'. The front of the house will be elevated at least 2' above grade. Rather than have 7 feet of fill dirt in the back, I would like to have a regular slab only in the front part of the house---then have the foundation drop to a partial walk out basement in the rear of the house. Even though it would only have a 6' or 7' clearance, it would be a great place for the water pump and other mechanicals. There is absolutely not a water table problem.

Since elevated terrain is practically unheard of in south Louisiana, 'basement' seems not to be part of our vocabulary. I want something totally walled off, sealed with doors, and a concrete floor--- like a basement. Is a partial basement not practical? Would the foundation not be as strong or secure? Are there any special problems I need to be aware of?---other than finding someone to build it.

Any advice would be appreciated.

Comments (9)

  • bus_driver
    16 years ago

    Reading between the lines, it sounds as if the general contractors are reflexively discounting your idea. Your idea sounds good to me. My suggestion is to ask the GC that you would prefer for the names of his preferred excavating and masonry contractors. Talk with them. If they subscribe to your concept, have them talk with the GC. Once the foundation is in, the work of the framers is the same. Do use a foundation drain system and waterproofing on the below-grade masonry. Good luck.

  • lsst
    16 years ago

    We are on a slope- front to back. The front half of our house is a crawl space and the back half is a walk out basement.

    We have a concrete wall that seperates the two. This wall is a load bearing wall.

    Our foundation is very secure but we have clay soil. I do not know what kind of soil you have though.

  • emmachas_gw Shaffer
    Original Author
    16 years ago

    Bus driver, you read very well between the lines! I keep hearing, "We don't do it that way here." Thanks for the suggestion. Talking directly to the sub is a great idea. If he understands what I want and knows how to construct it, the GC should not object. By foundation drain system, do you mean the perforated drain pipe that is installed outside the foundation? Or is there something else I need to know about. I need a crash course in basements!
    Thanks for responding.

  • bus_driver
    16 years ago

    My suggestion is to plan a higher wall than the desired depth of the basement, at least one block higher if using the standard concrete blocks. Put the perimeter drain outside plus put a perimeter drain inside, both protected from silt intrusion. Use 6" of washed stone fill inside to get the floor level above that of the drain system. Use heavy poly vapor barrier on top of the stone, then concrete. Should groundwater under the floor ever be an issue, this system will carry it off and the floor will remain dry. In this case, you will need all the expertise. The contractors are not going to learn all this for just your one job. You learn, design, and instruct them. That is the only way to get what you want under these circumstances. One of their reasons for reluctance is that they do not presently know how to do any of this. Do lots of Internet research. Design as if water will be around and under your basement. Give the water some easier place to go rather than into your basement.

    Here is a link that might be useful: One link

  • bus_driver
    16 years ago

    Consider this for the interior drain- with the stone raising the floor slab above this system.

    Here is a link that might be useful: Consider this.

  • emmachas_gw Shaffer
    Original Author
    16 years ago

    Bus driver, Thank you! You are wonderful!! I think I've been tutored by a pro! With all of this info, I think all of those heads that have been turning rapidly from side to side may finally, reluctantly, bob up and down a bit.
    A basement is a unique request in south Louisiana. No local GC I've talked to admits to ever building one before. Our small subdivision has bluffs. Most of our neighbors' homes have from 5'to 9' of fill dirt on one side. The deep footings required with that much fill seem to pose a real problem for the contractors. When we built in the same subdivision 12 years ago, I insisted the garage wing be stepped down 30" in the back to avoid so much fill (still needed 3'). After much teeth grinding, it was finally agreed to. But, although it turned out beautifully, you would have thought I committed heresy. So you can imagine what the word 'basement' does!
    Thanks to you who responded I now know what to look for, what to request, and what to expect in the work. You've armed me with knowledge. And, I know what to call it. It IS a basement.
    Extending to 8' is a great idea. The front would probably look better raised a bit more. I do understand the retaining wall description if I need it. And, I love the glass door idea. The natural light will be great to have.
    For the first time, I feel fairly confident I can get this done---as soon as the teeth grinding ends. Thanks to all of you.
    Bus driver, thank you, thank you for the link! This is info I'm sure I will have to provide to the GC. Please, please stay tuned to this forum.

  • lsst
    16 years ago

    emmachas,
    Go for it!
    We, too ,have the french doors for even more light and plan on finishing the basement in the future.
    In our situation having the crawl space in the front half of the house required less digging. That saved us money.

  • mightyanvil
    16 years ago

    Any GC who said "that's not the way we do it here" would not be a very good candidate in my opinion. Keep looking. You'll eventually find someone who respects owners enough to build what they want.