I am looking at renting a handheld coring drill and 4 " coring bit to
drill some ( about 12 ) weep holes in a 8" poured retaining wall (
all easy access) . The wall is also face with brick where I want to
to drill about 3 more holes . How long would this take with a hand
held wet coring drill per hole ? .
As far at as the economics - A local concrete cutting contract wants
about $5/inch of depth for a 4 inch diameter hole - t $40/hole for the
unfaced portion, $60/hole for the brick faced portion . I can rent the
rig for about $135 /day ( includes at Hilti handheld wet drill with a
4" X 12" coring bit
w/unlimited wear included .
Can I save any substantial $ by doing the job myself and is it
Recommendations and tips are appreciated . -thanks
With a larger frame mounted wet core drill, I would budget 30
minutes per hole. Much of this time is for bolting up the frame
work; the actual drilling, if the bit does not get hung up, would
take 5-10 minutes, and additional time to remove the core and take
down the frame. The frame functions like a drill press and allows
you to keep steady controlled pressure on the bit. With the hand
held in the horizontal, you will have to be the drill press. The
bit needs a fair amount of pressure to maximize the cutting speed
of the drill and a generous amount of water to cool and clear the
bit. You will probably be wet, muddy, and tired.
The bits are expensive and a 4" bit is close to the maximum
capability of a hand held drill. The core bit can get in a bind
if the drill does not keep running straight. There is the
potential to lose the bit and the hole if a sliver of reinforcing
steel wedges the core drill in the hole. I am not trying to scare
you away from the project, but rather give you as much information
as possible before making your decision.
Keep the whole world singing . . . .
DanG (remove the sevens)
4" diameter seems over kill for weep holes. Smaller holes would be a
lot easier - say a 1" masonry bit & a hammer drill. I assume you have
some sort of filtering medium behind the wall (i.e. landscape cloth), &
gravel, which may try to ooze through. 4" holes may also be inviting to
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