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Removing a flash wall

Houghton123 | Posted in Construction Techniques on May 3, 2007 11:02am

At one corner of our house, previous owners (about in the 1950’s) poured a flash wall, intended to keep the foundation from earth contact.  They did it badly, so it’s been something of a water trap, thus leading to one of my “before I can remodel the kitchen, I have to do this” projects, and I’d like to remove it.  It’s 4″ thick, about 6″ high, and about 24″ long.  I have yet to see any steel in the concrete here, so I REALLY don’t want to go at it with a hammer, since I don’t want to re-pour the foundation.

The local rental yard suggests nibbling it off with a diamond saw (score/break/score/break), which was my thought, too.  At $54/3 hours for a gas-powered wet saw, it’s more expensive than a diamond blade for my circular saw ($40); is it more powerful/faster, and, if so, by how much?  And how much will the grit from concrete cutting mess with an older pro-grade circular saw?

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  1. Piffin | May 03, 2007 11:35pm | #1

    I have never heard of a flsh wall before, but the dimensions you give are just a curb piece that I could pick up and walk off with.

    What is missing from this description?

     

     

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  2. Houghton123 | May 03, 2007 11:53pm | #2

    Sorry, Piffin, maybe it's local terminology.  This is a run of concrete poured against the face of the foundation, supposed to be just below the siding, supposed to slope out, and supposed to have some metal flashing between concrete and wood, so that water drains off, used around here when grade is incurably too close to the top of the perimeter foundation.  The trouble with this one is that it fails in all three of the "supposed to" features, so it contributes to, rather than guarding against, rot.  As a result, I've got several bits to replace (interestingly, the mudsill is intact; probably they used good redwood on that).

    This one is either bonded somehow to the foundation, or was poured as part of it.  Either way, I have no desire to go at it with the demo hammer, for reasons explained in my first post.

    Bill

    1. User avater
      ToolFreakBlue | May 04, 2007 01:08am | #3

      is it 4 inches x 6 inches x 24 inches long OR 24 feet long?I use an old worn out circ saw (crapsman) for cuting concrete like that.
      I would not use my worm drive in those conditions.
      TFB (Bill)

  3. sungod | May 04, 2007 01:58am | #4

    Flashwalls are the most useless thing I have ever seen. They usually pull away from the wall, which allows termites and more water go into the house.
    Original use for the flash wall is to keep water from entering the house, but the problem was cause by the adjacent grade being too high against the house.
    Solution is to lower the adjacent grade. You don't have to dig up the whole yard. Just a trench 6" wide, with brick to keep dirt out, running where it will drain to the lower portion of the lot.
    Most flash walls are removed with a wrecking bar.

  4. TheOldHandyman | May 04, 2007 02:40am | #5

    You don't say how deep that flash wall is. If it is less than a foot or so deep and there is no rebar in it, you should be able to break it up with a sledge alone.

  5. Piffin | May 04, 2007 03:12am | #6

    OK, I have re-read the whole thread. I can't see it and 24 inches long seems pretty small still but eeen if 24 feet long, I think a demo hammer or a jackhammer is the way I would do this.

     

     

    Welcome to the
    Taunton University of
    Knowledge FHB Campus at Breaktime.
     where ...
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  6. Houghton123 | May 04, 2007 05:39am | #7

    May I restate the core of my original question?  I'm reluctant to go at this with a sledge or demo hammer, because I'm not sure if the flash wall is part of the foundation, which is unlikely to contain steel, so not itself very strong.  I have NO desire to rebuild the foundation right now, so am planning to score the flash wall with a saw, break off chunks, and repeat until it either reveals that it's an add-on by falling off, or I've cut it back far enough that it's no longer creating problems.

    Should I spend $60 on a rented power diamond saw, or buy a diamond blade for my (old industrial-grade) Craftsman circular saw?  I'm inclined to the former - there must be some reason the rental yards carry them - but am most concerned about getting it done the quicker way.

    1. dovetail97128 | May 04, 2007 05:48am | #8

      Houghton123,
      Reading this thread leads me to offer this . Buy an inexpensive diamond skil saw blade, use your saw for a few cuts and trials at the breaking off. If it works to reduce the potential for damage( in your estimation) to the rest of the foundation but takes too long (in your judgement) then go ahead and rent the saw from a rental yard to finish the job. If the diamond saw in the skil saw works well enough for you then just keep using it.
      "Poor is not the person who has too little, but the person who craves more."...Seneca

    2. sungod | May 04, 2007 06:39am | #9

      Most splash walls are long and skinny. A diamond blade on a skill saw will only knotch it, cause its too close to the wall. A sledge hammer hitting the top will crack it into manageble pieces. A wrecking bar will crack it and pry it away from the wall. No picture?

    3. MikeHennessy | May 04, 2007 01:36pm | #10

      Rent the saw. You'll get twice the depth of cut with a big saw than you will with your circular saw. I think I understand that you'll be scoring perpendicular to the wall and cracking the flash wall off in chunks between the cuts. Sounds like a good place to start. Excavate around it a bit and, if possible, underneath. Giving it some room to move when you whack it helps -- A LOT! Get  yourself a rock bar to pry the pieces out after you crack them.

      Mike HennessyPittsburgh, PA

      1. Piffin | May 04, 2007 02:10pm | #11

        I agree. The way he describes trhis, he will need to cut nearly to the foundation thru this flash piece. But sixty bucks is an awful lot for a twenty four inch long chunk of crete. 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

        1. User avater
          Sphere | May 04, 2007 08:20pm | #12

          But a dang good excuse to get one of them diamond chainsaws!

          Man, I want one. Some of these old logs are as hard as 'crete.Parolee # 40835

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