Slab question...

[NYC]

I live in NY and wondering how deep of a foundation to pour for a Pompeii. I will be leaving my current oven alone and build the new one in another area. We generally pour a 6" slab for driveways to handle the weight of cars reinforced with steel mesh. How deep should I go for the oven footing?

[Les]

Re: Slab question...

Depends on the soil but a good rule of thumb is below the frost line.

EDIT... I should have said the footings should be below the frost line

[NYC]

Re: Slab question...

Our frostnline is 36" deep. I can see dropping a sonotube in the center but not anfull slab 3 feet thick. Any thoughts?

[Les]

Re: Slab question...

Correct - that's why I added the edit. A three foot slab would be insane.

[NYC]

Re: Slab question...

So then use a post digger on the corners and center down to 36" at about a 6" diameter and then pour it with a reinforced 6" slab for the foundation? What you think?

[Les]

Re: Slab question...

Sounds like it will work. I'd drop some steel in the holes as well. Do you know what type of soil you have?

[NYC]

Re: Slab question...

We have mostly clay here with maybe 12" of top soil on top.

[Les]

Re: Slab question...

Bummer - go deep.

[Neil2]

Re: Slab question...

Many have just used a floating 5-6 inch reinforced slab (rebar not WWF) regardless of the soil conditions.

Put a 3-4 inch layer of crushed ruck under the concrete slab and make sure this layer has positive drainage.

Frost heaving, if severe, may move your slab and oven around a bit, but if it is well reinforced it will take it OK.

To my knowledge, no one has on this site ever reported a failure in a properly reinforced slab due to frost action. (Underlined properly since a lot of the slabs I have seen here are clearly not done very well with respect to rebar placement.)

[NYC]

Re: Slab question...

After speaking to the mason who poured 3,000 sq ft for me last summer around the pool he said to go 30 inches down with 8" ID tubes in the 4 corners and center and then 8" reinforced slab on top of the stone base. I want to brick the cinder block base and top enclosure so it will bear alot of weight on this slab and also I do not want too much cracking in the mortar of the brick due to movement. Biggest hassle is getting this pour done fast enough with a mixer before it sets as I cannot fit a truck back there for delivery of ready to pour stuff like we did for the pool. That was before the brick wall and gate were built.

[RTflorida]

Re: Slab question...

What about a concrete pumper truck? My entire pool and surrounding patio was all done by a pumper from the street, I too, didn't have room for any heavy equipment to get to the back. The entire pool and all grading done with a bobcat. The cost is only slightly more than a standard concrete truck, you have to pay the labor of the 2nd man operating the end of the hose.
I have been down the road of mixing all of the concrete by hand for an oven, I won't ever make such a huge mistake to save a few bucks. 55 bags in 3 hrs damn near killed me, seriously.

I'm an original NE Ohio boy so I know your soil conditions well. Your latest idea seems to be spot on, just enough overkill with the extra slab thickness that you should have NO worries. I have never been a fan of the floating slabs in areas of heavy compacted clay soil. Frost heave can jack up an oven several inches, who knows what kind of cracking it will cause to a dome oven.

RT

RT

[NYC]

Re: Slab question...

I don't want to run a hose 100+ feet across my new pacers and pool area.