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  1. #1
    pup Guest

    Default Concrete slab over stumps

    I have a 24' x40' garage to build which will be of a pole barn type construction project. It is located in a timber area. The site is located where 2 6" tree stumps and a 12" stump are located. The trees are recently cut down for the garage and the stumps are flush with the ground. The customer does not want to have the stumps removed and just wants to pour the slab on the ground and over the stumps. Thier thinking is that the tree is dead since it was cut down. My question is can I do this and not have any future long term problems? I'd like to know the cons of doing this so I can be up front with the customer about future problems if any. The pros of this are obviously quicker construction time and expense in having to have a stump removal crew come in and do a removal. Thanks for any comments on this issue. pup

  2. #2
    Bob Kovacs Guest

    Default Re: Concrete slab over stumps


    As the stumps rot, the ground will settle under the slab, possibly causing it to settle. Given the small size of the stumps, it may never be a problem. Technically, though, the building inspector could shoot you down if he sees the stumps, since you aren't supposed to build over organic materials (roots, stumps, etc).

    Rather than having a separate "stump removal crew" come in, why not just have the excavator yank them when he digs the footings and preps the slab? A 6-12" slab is nothing for a backhoe (usually).


  3. #3
    Justin B. Jensen Guest

    Default Re: Concrete slab over stumps

    Pup -

    Ditto Bob's comments, and I'd add:

    If your client "forces" you to proceed with building over the organic materials, I'd have them assume liability for future failures related to slab cracking, settling and possible "bug" infestations within the building envelope, all of which are possible as the stumps deteriorate over time.

    I do not allow my clients to dictate building practices to me, afer all, it's my reputation to uphold. Our contract gives us complete control over the logistics of the project including materials and methods.


  4. #4
    pup Guest

    Default Re: Concrete slab over stumps

    Thanks guys and I agree with you. I guess I was just looking for some affirmation. Bob made sense with the backhoe/excavator idea but the problem is that there will not be one. The construction process will just be auger drilled holes with a tractor and a concrete base poured for the posts to sit on(pole barn). That seems to be standard proceedure here in the lower part of Illinois. Actually most contractors don't even do that much but just set the posts on the dirt and fill hole with dirt. The building will be in the timber so before pad is poured it will be termite treated so I'm not really worried about "bugs" as Justin stated although that could eventually happen. I mainly do commercial work where everything is dug out and filled with CA6, compacted in 6" lifts, rebar, then concrete. So pouring over the bare ground and stumps kind of threw me for a loop. It's actually a "weekend/spare time" job as the "customer" is relation and doing alot of the work themselves with me helping out when possible. Thanks again pup

  5. #5
    Mike OHandley Guest

    Default Re: Concrete slab over stumps


    I inspected a home a few years ago where the neighbor watched the contractor toss a bunch of stumps into the garage perimeter and then pour a beautiful slab over the top 12 years before. The slab had cracked badly in at least half a dozen places and was settled nearly a foot and a half at one side of the garage. Self-inflicted wound.



  6. #6
    pup Guest

    Default Re: Concrete slab over stumps

    I know what you mean. A friend of mine built a new house and had the basement contractor do all the concrete work while there (winter time). When they poured the garage approach/driveway you can now tell (3 years later) that they didn't compact the over dig in front of the garage door and the over dig has since settled causing cracking in that area of the concrete. It's a shame that not doing a step like that will cause unsightly problems later but it does happen. It just goed to show that you should have all your ducks in a row before completing a job and moving on to the next. pup

  7. #7
    C.S. Guest

    Default Re: Concrete slab over stumps

    This is the type of customer that harms everyone, contractor and consumer alike. I agree, get a release of liability stating why you don't guarantee the foundation if the customer refuses to let you pour the foundation on properly prepared ground. I volunteer for Homeowners Against Deficient Dwellings, and we would never condone doing what this client is asking for. The client must not recognize the false economy of taking such shortcuts. Frankly, I would refuse to do the job--as a painter/artist in the past I did at times refuse to do jobs that I could see were a disaster waiting to happen, and usually shortcuts were the basis of it.

  8. #8
    Doug Guest

    Default Re: Concrete slab over stumps

    Here is something to think about also. This report came to my by third person, so I don't know how accurate it is.

    A paving contractor was hired to pave a parking lot. And when the contractor arrived on site to pave it, they noticed that the sub-grade was too wet. At this point, they were going to leave and come back after the water had drained away, but the owner insisted that they pave it that day. The contractor had the owner sign disclaimers and assume responsibility since they new the asphalt would not last.

    Sure enough, the asphalt did not last and it ended up in court. The judge ruled against the contractor and told them, you were the experts and new better not to pave with the present conditions. So the contractor ended up paying for the removal of the asphalt and re-paving it.

    So much for having the owner assume all liability.

  9. #9
    C.S. Guest

    Default Re: Concrete slab over stumps

    To Doug, if the contractor is determined to take this job the release of liability may be seen differently by a different judge...but as I said, if it were me, I'd turn it down. the job could end up costing the contractor and owner a LOT. ONly ones likely to make any money off such a job are the lawyers.

  10. #10
    George Roberts Guest

    Default Re: Concrete slab over stumps

    I don't know.

    People around here pour floors with sufficient rebar and thickness so they don't break if/when they settle.

    I don't know what the design details of the floor are and I don't know enough about the site to make comments about what should be done.

    I don't even know if you are covered by a code. Most require organic material be removed.

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