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  • Started digging, stopped digging. Water problems.

    Greetings all.

    I've been lurking here for some time now, and only recently joining the site. I've looked at the various builds, downloaded the available plans and guides, have found local suppliers for needed goods.

    I've been doing all of this for a friend with a big backyard that wants to build an oven. Here's the view from the back door of the house:



    The idea is to put the oven in the far corner of the lot, just to the left of the yellow machine.

    He's decided on the 42" Pompeii. From the guide it recommends an 80"x96" concrete slab. He spent some time staking it out, then started in with the auger. We're in the northeast, most footings are at 48" to get below the frost line. The plan was to sink four 8" Sonotube footings into the ground.



    $75 for the day for the machine. Makes very short work of the hole. Looks like about 4" of topsoil, another 5" of sand/clay mixture, then it appears to be all clay.

    We got down to 40" pretty quick on the first hole, auger spinning very nicely. We noticed though that the spinout was turning a little muddy, looking a little wetter the further down we went. Pulled the auger up and out, and found this:



    After watching it a minute or so it became this:



    The water was almost spurting from the side of the hole about 12" down or so, filled up pretty quick. Sides collapsing in. Reminded me of digging in the sand at the beach.

    We then drilled in another about 40' away, in a slightly higher area of the yard. Same thing.

    So here's the question: Do we need the footings? I remember reading in another thread on this forum that with enough trap rock as a base, allowing for drainage, it's possible to "float" a slab. Excavate the area, at least 6" of trap rock, then pour the slab on that? Quite often done up in Canada for detached garages. Could anybody give any insight into this method?

    Or, if we need to have the footings, we'll have to wait until summer to do the digging, when the water table is a little lower.

    All help will be most appreciated.

  • #2
    Re: Started digging, stopped digging. Water problems.

    If it's really "all clay" down below, your water is running on the top of the clay. Clay does not give up water that fast unless it has sand stringers in it. A pure clay is quite "tight". How thick was the clay (how deep could you go?)

    Bail out the hole a few times and see how fast it recharges. It could just be local drainage from the sand/gravel interface on top of the clay layer.

    If you have slope to the property, you could put in some draingage pipe and let gravity do the work.

    do you know any friendly builders in the area...you could find out what types of foundations are put it there.

    Jim
    sigpicTiempo para guzarlos..... ...enjoy every sandwich!

    Comment


    • #3
      Re: Started digging, stopped digging. Water problems.

      Jim, thanks for all the replies.

      I know that the soil does dry out over the course of the year, every 4th of July there's a hole dug (near where we dug hole #2) for a bean pot cook to happen, it's dug at least 36" down, no water is seen at that time.

      Here's the thread I was referring to for doing a foundation pour without footings:

      http://www.fornobravo.com/forum/27356-post7.html

      I think it will work just fine, but I'm having a hard time convincing the owner (and $$$ provider). Anybody with horrendous results that wants to add in?

      Comment


      • #4
        Re: Started digging, stopped digging. Water problems.

        The key thing on that foundation comment by David is the drainage. You want to keep that coarse material drained to avoid the freezing/ frost heave issues.

        I doubt that you're going to have damage the oven if the hearth slab is well reinforced. Consider the hearth and oven as a monolithic unit on your separate floating foundation unit.
        sigpicTiempo para guzarlos..... ...enjoy every sandwich!

        Comment


        • #5
          Re: Started digging, stopped digging. Water problems.

          Originally posted by jbaker View Post
          From the guide it recommends an 80"x96" concrete slab.
          My plans say 77" x 86" foundation for a 42" oven. Am I looking at the wrong spot?
          Mike - Saginaw, MI

          Picasa Web Album
          My oven build thread

          Comment


          • #6
            Re: Started digging, stopped digging. Water problems.

            I've been going by the plans I downloaded off this site. Here's a cut and paste of the materials list for the Pompeii:

            Material List 42" Oven
            80" x 94" Foundation

            (46) 80lb bags of Ready-Mix concrete
            (8) 10' lengths of 1/2" rebar, (4) cut to 80";(4) cut to 94"
            (4) 2"x6"x8' studs for framing, (2) cut to 83";(2) cut to 94"
            (48) sq ft of wire mesh
            (12) rebar stand-offs
            (104) sq ft of 6 mil plastic sheeting
            Handful of plastic zip-ties, or ball of tie wire
            1/2 cu yd of gravel
            (1) box 2 1/2" framing nails


            etc.....

            From this link to the Forno Bravo storefront:

            Instruction Manuals & e-Books :: Forno Bravo Store

            Look on page 58

            And I just found this while going way back in the forums:

            http://www.fornobravo.com/forum/f6/p...lans-2265.html

            Now I see where your question lies.
            Last edited by jbaker; 04-06-2008, 06:00 PM.

            Comment


            • #7
              Re: Started digging, stopped digging. Water problems.

              Originally posted by Xabia Jim View Post
              I doubt that you're going to have damage the oven if the hearth slab is well reinforced. Consider the hearth and oven as a monolithic unit on your separate floating foundation unit.
              So you're saying (and I promise I won't hold you to this) the idea of a 6.5" well reinforced slab of concrete over a foot (or better) of well drained compacted trap rock will provide a stable foundation for the rest of the build?

              I guess our biggest concern is whether we're going to have a slab that will go off level in a big way. A slight adjustment off of level is certainly not a major problem.

              I've been hitting out to some of other builder forums, seeing what I can find. Too much info sometimes is not a good thing. Makes one's head hurt.

              Comment


              • #8
                Re: Started digging, stopped digging. Water problems.

                Originally posted by jbaker View Post

                well drained compacted

                Too much info sometimes is not a good thing. Makes one's head hurt.
                well compacted and well drained.....

                Let me mention a worst case scenario....a good friend of ours has a house built on sand along Lake Michigan. Over a few years we noticed his porch was sagging. Slab on the ground, column up to porch, column up to roof.

                We could sit on the beach and look back at his house and it had a remarkable tilt to the roof for 1/3 of his porch due to the settling of the concrete slab. (even before the wine ) The slab was cracked and pulling away from the house,

                Okay, that long story followed by a contractor who came in and pumped concrete under that slab and raised the whole shebang back into place, nice and level.

                Now I don't believe you will ever experience that kind of problem and do believe that the foundation reference by David will work in your case....again, talking to you local contractors never hurts either.

                That last comment of yours is so true....but it's also how you get a comfort level to go ahead....

                Do let us know what is decided....
                sigpicTiempo para guzarlos..... ...enjoy every sandwich!

                Comment


                • #9
                  Re: Started digging, stopped digging. Water problems.

                  Somewhere I've got pictures from when they straightened the Leaning Tower of Pizza ....er, no, that's near Detroit at Dominoes Farm.....yeah, the Leaning Tower of Pisa in Italy...right!

                  They dug down, put a collar on the tower and stacked lead weights on the upslope side.....actually brought it back from leaning too far over. (there is surely more to that but it was quite an engineering job)

                  Good old Wikipedia Leaning Tower of Pisa - Wikipedia, the free encyclopedia

                  On 7 January 1990, after over two decades of work on the subject, the tower was closed to the public. While the tower was closed, the bells were removed to relieve some weight, and cables were cinched around the third level and anchored several hundred meters away. Apartments and houses in the path of the tower were vacated for safety. The final solution to prevent the collapse of the tower was to slightly straighten the tower to a safer angle, by removing 38 m3 of soil from underneath the raised end. Through this, the tower was straightened by 18 inches (45 centimeters), returning to the exact position that it occupied in 1838. After a decade of corrective reconstruction and stabilization efforts, the tower was reopened to the public on December 15, 2001, and has been declared stable for at least another 300 years
                  sigpicTiempo para guzarlos..... ...enjoy every sandwich!

                  Comment


                  • #10
                    Re: Started digging, stopped digging. Water problems.

                    Originally posted by Xabia Jim View Post
                    While the tower was closed, the bells were removed to relieve some weight, and cables were cinched around the third level and anchored several hundred meters away.
                    Yikes. I'm thinking we should wait until the groundwater subsides, then dig the holes and sonotube it. Quite a bit cheaper than the cost of 300 meters of cable, and less stress on the neighbors.

                    I think I'm going to recommend we start stockpiling the needed materials, wait until the water drops, maybe do the holes around July 4th (the owner of the land where this is going wanted to have it in by then. Insert another smiley face <here>). He usually has lots of family visit over that week, extra hands mixing the concrete wouldn't be a bad thing.

                    Comment


                    • #11
                      Re: Started digging, stopped digging. Water problems.

                      Originally posted by jbaker View Post
                      I've been going by the plans I downloaded off this site. Here's a cut and paste of the materials list for the Pompeii:
                      I see what you are referring too. On page 13, the foundation size is listed as 77" x 86". There seems to be a discrepancy. James?
                      Mike - Saginaw, MI

                      Picasa Web Album
                      My oven build thread

                      Comment


                      • #12
                        Re: Started digging, stopped digging. Water problems.

                        Don't sweat the little stuff. There's a few procedural errors and typos in the plans. Adjust and modify for your needs. Read them, then re-read them. They make sense and you will find the errors. This is not rocket science. Simple math will get you through. If you have a serious question that worries you, ask and you will be answered.
                        GJBingham
                        -----------------------------------
                        Everyone makes mistakes. The trick is to make mistakes when nobody is looking.

                        -

                        Comment


                        • #13
                          Re: Started digging, stopped digging. Water problems.

                          Why do they want the oven so far from the house? That is a lot of steps to take pizza fixins, meat or bread back and forth from the prep site. I just want to make sure you think of that.....I know nothing about foundations, etc.

                          Comment


                          • #14
                            Re: Started digging, stopped digging. Water problems.

                            Originally posted by krosskraft View Post
                            Why do they want the oven so far from the house? That is a lot of steps to take pizza fixins, meat or bread back and forth from the prep site. I just want to make sure you think of that...
                            I must agree.... Closer is
                            better.
                            My thread:
                            http://www.fornobravo.com/forum/f8/d...ress-2476.html
                            My costs:
                            http://spreadsheets.google.com/pub?k...Xr0fvgxuh4s7Hw
                            My pics:
                            http://picasaweb.google.com/dawatsonator

                            Comment


                            • #15
                              Re: Started digging, stopped digging. Water problems.

                              I would agree with the distance, this isn't a firepit where all will be sitting around chit chatting for hours - long way to haul good eats.
                              Sorry I can't help with the foundation. In FL we can pour a slab right on the ground (over a few inches of gravel or course). I grew up in northern Ohio with a 36" frostline but never experienced water problems nearly as bad as yours; just a minor basement leak or two and never any water issues in building many decks and fences where we had to dig down the 36".

                              What happened to UNO, our resident concrete/foundation expert? He would certainly have a viable answer.

                              RT

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