Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I
have got a 230mm angle grinder, but that would only go to about 75mm
depth, and is a beast to use anyway (i.e., I'd rather not use it up a
ladder). I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

thanks,

dan.