drill hole on insulated wall

I would like to install an extractor fan on the bathroom wall. The wall has been insulated with kind of black beads.
I have some worries.
Is there any good idea to stop the bead within the cavity flowing out when I
dig a big hole through the wall? Will the beads catch fire when drilling?
Could you recommend a proper tool for drilling
thanks

There is no way of preventing the loss of insulation whilst drilling but you can sleeve the hole with a length of drain pipe once you are through.

Or, you can reach in and pack the cavity with some glass fibre (cavity batt) insulation to prevent loss.

I doubt you will create the conditions needed to ignite the insulation.

Thanks.
Does it make any difference when drilling a wall from outside or from inside?
I drilled a wall to install a washing discharge pipe before.
I assume the hole for an extractor fan is much bigger.
Could anyone suggest a better powerful tool enable to do the job quickly and easily.

noseall said:

There is no way of preventing the loss of insulation whilst drilling but you can sleeve the hole with a length of drain pipe once you are through.

Or, you can reach in and pack the cavity with some glass fibre (cavity batt) insulation to prevent loss.

I doubt you will create the conditions needed to ignite the insulation.

Click to expand...

davidps said:

Does it make any difference when drilling a wall from outside or from inside?
I drilled a wall to install a washing discharge pipe before.
I assume the hole for an extractor fan is much bigger.
Could anyone suggest a better powerful tool enable to do the job quickly and easily.

Click to expand...

Often when the drill gets to the last inch or so it knocks the face off the brick/roughcast/plaster untidily. To prevent this ideally you drill a smaller pilot hole right through, then use a core drill from both sides through to the cavity, thus any untidy bits are inside the wall. Obviously you need a long drill for your pilot hole, since it needs to go through two thicknesses of bricks plus a cavity.

This type of thing will make the job easy...
http://www.hss.com/g/1121/Light-Duty-Diamond-Driller-Kit.html
Our local hire shop hires them cheaper, so maybe shop around a bit.

Also our cavity insulation has a "glue" mixed into it, so you might find there'll be minimal loss once some loose stuff falls out.

Or the glue may have failed (as its not that uncommon) and the balls will spill out until there’s none left above the hole!

Be sure to capture the moment it on video for Youtube.