Core drill bit recommendations

[Milleniumaire]

I recently replaced an extractor fan in a bathroom when it failed after 13 years - installed when the house was built. To my surprise, I noticed it was only vented to the loft space above the bathroom, so I decided this needed to be resolved, by venting it through an outside wall.

The ducting for the extractor is 100mm and I need to purchase (or hire?) a 100mm+ core drill bit, but they all seem to mention use with brick or masonary, whereas my house is built from stone.

Now, I know from experience that drilling through stone is a lot harder than drilling through brick or masonry and for a large hole this will be made worse due to the random nature of the stone i.e. an uneven surface and multiple pieces of stone to be affected by the hole.

Whenever I've drilled into stone before I have ALWAYS used the hammer action function on my drill, but I notice with the core drill bits I've seen they state not to use the hammer setting. I've no idea how these things would expect to drill through a stone block without using hammer action!

Now obviously there are some very expensive, quality, diamond tipped core drill bits out there, but for the price I would pay for one of those, it would be cheaper to pay a tradesman to do the job as he's more likely to have the required tools.

I would appreciate any recommendations of what 100mm+ core drill bit to purchase for this job.

 

[bernardgreen]

It is a stone wall or a rubble and mortar wall ? ( Stone being rectangular shaped pieces of stone. )

If rubble and mortar then it may be better to excavate a hole through the wall by removing stone by stone. I had to do this through 2 feet of rubble and mortar and it took less than an hour. Then fill any voids with lime mortar and small rubble.

 

[Milleniumaire]

It's a random stone wall. I wouldn't describe it as rubble and mortar as most of the stone pieces are a decent size, but obviously they are all different. I have tried to find an area close to the extractor that would just require maybe one piece of stone to be removed, but this isn't possible due to the size of the stone.