Started digging, stopped digging. Water problems.

[Xabia Jim]

Re: Started digging, stopped digging. Water problems.

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....

[jbaker]

Re: Started digging, stopped digging. Water problems.

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.

[jbaker]

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.

[mfiore]

Re: Started digging, stopped digging. Water problems.

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?

[Xabia Jim]

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.

[jbaker]

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?

[Xabia Jim]

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

[jbaker]

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.