I'm planning to install an air-conditioner so will have to drill a 90mm hole through a cavity wall (brick & concrete block). I have done lots of DIY but not this job. Based on a bit of research I think that I'll buy a diamond edged core bit rather than TCT because even though it's only the one hole I'll pay the extra for less effort. I already have a 1.25KW SDS drill with clutch (yes I know I must use it with hammer off) so I think I'm good to go. Except for one thing - the air conditioner is to be fitted to an upstairs room.
I have read advice that it is a good idea to drill from both sides, however even if that is not essential I assume I would get a cleaner hole by drilling at least a little from the outside. But that means using a ladder (I am certainly not hiring scaffolding just for this job!). The instructions on my drill state that it has a clutch but that it still needs to be held firmly for it to operate and that I should never drill from a ladder. Is this 'over-cautious' advice or should I definitely rule out doing any drilling from the outside?
I have done lots of chasing on the inside so I'm OK about screening off the wall to contain the dust, and I guess I'm not too bothered about the outside hole being a bit ragged when I cut through as the air conditioner umbilical and condenser unit are hardly attractive.
Also the instructions say that the hole should be at a slight angle downwards. Presumably I just need to start the drilling slowly and carefully whilst only one side of the cutter has any contact?
I have read advice that it is a good idea to drill from both sides, however even if that is not essential I assume I would get a cleaner hole by drilling at least a little from the outside. But that means using a ladder (I am certainly not hiring scaffolding just for this job!). The instructions on my drill state that it has a clutch but that it still needs to be held firmly for it to operate and that I should never drill from a ladder. Is this 'over-cautious' advice or should I definitely rule out doing any drilling from the outside?
I have done lots of chasing on the inside so I'm OK about screening off the wall to contain the dust, and I guess I'm not too bothered about the outside hole being a bit ragged when I cut through as the air conditioner umbilical and condenser unit are hardly attractive.
Also the instructions say that the hole should be at a slight angle downwards. Presumably I just need to start the drilling slowly and carefully whilst only one side of the cutter has any contact?