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.
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.
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