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Rock Breaking
How to get rid of a very large rock that is in an inconvenient place
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The problem
When digging the foundations for the main house a rock was found that was way too big for the excavator to move.
Various methods
There are various method such as...
Wedge and feathers
You drill 3/4" holes and then hammer them in in sequence. The picture shows my attempt at using 3/4" wedge and feathers but it did not cause any rock splitting. Each wedge with its two feathers costs about $12 and they are rarely reusable. You would need hundreds of sets for a large rock.
Wedges and chisels in sawn slot
Use a diamond cutting saw to make a 3" deep groove and then hammer masonry chisels into the groove to hopefully get the rock to crack. The technique has some potential but in my case the rock was just too big.
Jack hammer
A jack hammer is a useful tool for dealing with very hard ground and for concrete, but is no match for a large rock.
Expanding resin
The technique was not tried. It requires drilling a large number of 1.5" holes and filling them with expanding resin. The resin is fairly expensive and so is a 1.5" masonry drill bit. With the right equipment it is ok drill a hole, but it takes a long time to drill the large number of holes.
Dynamite
This was not tried because of the large number of regulations and restrictions.
Fire
This was found to be by far the most effective method. You build a very hot wood fire to thermally stress the rock to cause it to crack.
Fire is best method
Once the rock is reduced in height and width such that it is no longer in the way it can be covered with soil.
The broken off bits of rock can be used to make a rock wall or rock garden or whatever.
