I want to drill a hole through the external wall backing the loo to install
an extractor fan assembly. The fan will be in the ceiling, and the duct will
go from here in the loft space to the outer vent which will be in the cavity
wall.. I don't like heights and would rather drill the vent hole from
inside the loft, through the cavity wall to the outside. My worry is the the
drill will split the wall on the outside and make a horrible mess on
emerging. The chap from whom I will hire the drill and tool assures me that
the tool will emerge from the outer wall cleanly without chipping it. Has
anyone here had experience of this sort of thing, and reassure me???
On Thu, 14 Sep 2006 12:59:05 +0100, "steve marchant"
If it is a core drill it may emerge cleanly, depending on the
operator. It is better to drill a pilot hole and use from both sides
If any sort of hammer drill, he is lying and it will smash the bricks
off the emerging side if used one way. Again it depends on the
operator how much damage is done.
There is almost bound to be some but I expect that he means not enough
to show when the outer draught-excluder plate is fitted over the hole.
You can stick a small diameter pilot hole through first and see what it
does, by way of reassurance. If that spalls off a big chunk, then the
core drill probably will too..
You can put a marker on the drill at a depth equivalent to the wall
thickness and take the last part very gently.
Me, I would put a pilot drill through from the inside, counter-bore at
least an inch or so (the more, the better - ideally at least 1/2 a
block/brick thickness) from the outside and then bore the remaining
depth from the inside - again going gently for the last bit.
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