Drilling through granite

2 Aug 2010
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United Kingdom
I have just removed a bathroom suite from a 160 year old granite cottage and the toilet used a massorator. I want to now put in a soild pipe on the external wall and a have it come into the building in the location of the new toilet.

How to a drill a large enough hole in a solid granite wall to accomodate the waste? Does anyone know what tool might do the job?

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How thick is the wall ?

Is it cut granite-blocks or random granite "stones"?
You would need a high-speed drill and a good grade diamond holesaw. Granite fabricators use a bit called a DRB01375, made by Alpha but I don't know if this is available in your area. This is a bit that you can use either wet or dry and will cut through a 3/4 slab in less than 30 seconds but would take longer on your wall depending on thickness. The largest size is 2", I'm not sure if this is big enough for your requirements.
The wall is about 3 foot thick and of random granite. I'll post some pictures tomorrow.
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My opinion , forget about drilling it.

Just use an SDS with broad or pointed chisel and start removing the stones by cutting out the mortar.

This WILL end up with a damn big hole but the best method.
its not the news you wanted to hear but if your doing it yourself then mointainwalker is right.
mointainwalker - thanks. I think your idea might be the cheaper option for me as hiring kit is going to be really expensive.

The wall I'm planning on placing the soil pipe through a wall that is on a gable end and cant bee seen from the outside recreational space. So having a big hole that I have to make good wont be too much of a headache.
View media item 24811Here is a photo of one of the walls. I'm no expert but I think they are in quite good condition and at fairly even.

I think Ill carefully use a hammer and chisel to make a hole in the wall for a soil pipe and then i'll in after.

I'm going to lime render the walls, leaving some of the quoins exposed.
Looks very nice, but as someone said, if you expose the quoins, condensation is guaranteed
assuming you have an sds drill it may serve you well to get a 3ft long 15mm or so drill bit at the very least to drill through so your holes don't end up not quite meeting eachother as you will have to attack it from both sides.

Also time spent stitch drilling around the perimeter from both sides will be well spent. This is of course assuming that a normal masonary sds bit will make a dent in the granite, which it may not.

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