# Excavating limestone.



## Equitas (May 18, 2004)

Next year I am hoping to excavate to start building.The thing is I am stuck as to which would be better way.

The land we have is 8 inches of dirt covering limestone layers.I am thinking of using a walk behind stone saw to cut the layers into workable sized blocks to use in some aspects of building.Other option is breaker attachment on excavator.

If anyone has any thoughts and ideas I would appreciate them.

Thank You.

Rolf


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## Beeman (Dec 29, 2002)

We've got a lot of limestone around here. I've never seen anyone cut them or use them for anything when excavating. In most cases they have had to drill and blast even for a basement. Other problem is the limestone tends to move around. My garage has moved quite a bit in the last 8 yrs. Limestone areas also tend to have sinkholes and underground caverns.


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## Darren (May 10, 2002)

Beeman is correct. Find out if you're in a karst (underground caves created when the limestone is dissolved) area. The local county NRCS office should be able to help you. The other option is to build your house on a slab and forgo the basement. If you do rip out the rock make sure you don't end up with a wet hole in the ground. I'd look at ways of draining the hole before I excavated. Can you run a ditch to a lower elevation to provide a perimeter drain if necessary, etc.


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## Beeman (Dec 29, 2002)

Poured concrete slabs always tend to crack around here due to movement of the rock underground. I have seen sites completely excavated and then refilled and packed properly with material to build a good base for a commercial building slab.


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## Equitas (May 18, 2004)

Beeman said:


> We've got a lot of limestone around here. I've never seen anyone cut them or use them for anything when excavating. In most cases they have had to drill and blast even for a basement. Other problem is the limestone tends to move around. My garage has moved quite a bit in the last 8 yrs. Limestone areas also tend to have sinkholes and underground caverns.


Hello Beeman,

What do you mean moves around  Moved as in sinks, rises, side to side? I was figuring the limestone would make a good foundation. I am not excavating a basement really lower level into a hill side.Would you have any good websites or books I could read.Thanks.

Rolf


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## Equitas (May 18, 2004)

Darren said:


> Beeman is correct. Find out if you're in a karst (underground caves created when the limestone is dissolved) area. The local county NRCS office should be able to help you. The other option is to build your house on a slab and forgo the basement. If you do rip out the rock make sure you don't end up with a wet hole in the ground. I'd look at ways of draining the hole before I excavated. Can you run a ditch to a lower elevation to provide a perimeter drain if necessary, etc.


Hello Darren,
I was going into a hillside so drainage would be no problem. Thanks for the info.Do you have any good websites or books I could read.

Rolf


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## Beeman (Dec 29, 2002)

I have no websites or books but would recommend you talk to your county ag agent or highway dept., also soil conservation. I am sure they will have a lot of knowledge about limestone. I know from contaractors and my own experience with limestone in our area. When a road is built many times they excavate all of the limestone and then re-fill and pack the road bed to create a solid base. When they built a commercial building here in town I questioned the engineer why they were digging a basement. He explained that they weren't digging a basement, they had to dig deep enough and remove limestone to gain a stable base for the slab. They then refilled the hole in layers and packed each layer. The limestone around here actually pops out of the ground like I'm growing rocks. Last year I found a man in my driveway taking notes. He was a geologist studying the limestone ledges and mapping them in my area.


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## Lt. Wombat (Jul 3, 2003)

In the Black hills the limestone "decomposes" once exposed to air. All I know from personal experience is we have the dig out piles from when the house was built in 1997. Even the bigger chunks can be crumbled by the goats climbing on it. Super flimsy stuff.


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## Equitas (May 18, 2004)

Sorry it took so long to get back to you guys.Almost forgot about this thread.Thanks for the responses.


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## MELOC (Sep 26, 2005)

my brother had a rancher he wanted to excavated under to install a wood stove/furnace. at the very end of the house was a large outcrop of limestone. we rented air hammers and drills. it was good so far into it and like someone said, the outer layers are brittle but the inner limestone is super hard. we were never able to remove what we needed and decided on just a small 3 foot tall area to duck through. that is the best we could do without having someone blast (which was not even an option as the limestone was right under the house).

if you have a few years, let the limestone "weather". the outside will get brittle as it oxidizes.
ever seen a large piece of machinery pounding away at the earth at a construction site? chances are it was limestone.


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## Beeman (Dec 29, 2002)

Equitas said:


> Sorry it took so long to get back to you guys.Almost forgot about this thread.Thanks for the responses.


 Well? What did you do?


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## Oilpatch197 (Apr 18, 2004)

I thought the Limestone gets brittle from Freezing water on it, and eventually cracks it, I guess not.


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## solidwoods (Dec 23, 2005)

The surface stone does (below frost line)
Holes filled with water to freeze is what old timers used to do.
You can't economically cut a usable product, get the caps and mats.
(that's the dynimite man)
Eventhough I would'nt rec. blasting (last resort, you have to have it, and site survey done by a Geo. pro.. blasting can cause side effects that you don't want, and may not be able to fix)
jim


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