Here's the situation. I have a stamped concrete patio where
the concrete apparently was not finished off with the proper
consisten pitch so that water will drain. There are two areas
where pools of water remain after the rain. Both of these
happen to be in areas where there are relief cuts in the
concrete. It appears that these cuts only go about half way
through the concrete. Which makes sense I guess, since
for the purpose of relief cuts that is sufficient.
So, my idea is to cut them the rest of the way through in the
area of the puddles so the water can then drain. I'm thinking
about 10 ft or so is all I need in total and I'm thinking about
using a circular saw with either a diamond blade or else one
of those abrasive saw blades that also say they will cut
concrete. The difference is the diamond blade is $40, while
the abrasive ones are $6. I obviously don't care if it takes
a bit longer with the abrasive blade, but I don't want to have
to go through 4 blades and have it take 3 hours either. I think
we can assume the remaining concrete is about 2" thick.
Any thoughts? Anyone do anything similar with one of
the abrasive type blades? Thanks.
On Sat, 30 Jun 2012 12:51:50 -0700 (PDT), " email@example.com"
I cut a number of pavers - all the way through - with an abrasive
blade. You could see it wore down about an inch. Old 6 1/2" saw.
Hard to say, but a guess is you might need 4-6 blades to do 10' by 2".
How about drilling some holes instead?
Why don't you drill a few 1/4" holes through the concrete in the relief
cuts instead ?
Use a long drill so the water will more easily / quickly be absorbed in
the ground under the slab.
Unless there's a lot of water that pools on the slab - or you're
impatient about how long it takes for the water to drain, then one (or a
few) small holes should suffice.
I don't think that's a good idea. If it *does* drain, you'll get
scouring under the slab-- or you could get muddy water coming *up*
when it rains.
Not to mention that all the re-wire or rod, if they used it, is below
that cut and you don't want to cut it--- nor will either the diamond
blades, nor the abrasive ones that I've used, react well to the iron.
I'd be inclined to widen them if they end someplace that can take the
I got 3 wet/dry diamond blades off ebay for about $30 [free shipping]
many years ago. The first one cut a 2" slab for 60' & was looking
good until I tried another slab with a re-rod in it. It stopped and
died at the iron. The second one, I adjusted so it didn't hit iron
and it is still in that old B&D that I abuse with such shenanigans.
I've cut a pile of block, brick, concrete and stones with it.
I trickle water in front of the cut so I'm dealing with mud instead of
dust. I've never even tripped the GFCI.
HF has the blades for $20--
I've never had an abrasive blade that would last 1/20th the amount of
the diamond blades--- and they throw off a whole lot more stink &
dust. Maybe they're better these days. I haven't bought one in
I would ditto Jim's advance & experience,
the diamond blades that I have used that were rated for cutting
reinforced concrete made short work of the occasional piece of rebar.
The same goes for wet cut Hilti diamond core bit.
Somewhere kicking around little chunks of #9 bars that cut partially
severed with a Hilti core bit.
Get the diamond blade.
I bought my first diamond blade (6-1/2") nearly 30 years ago & have
gotten great use out of it.
In those days they were pretty spendy.
SInce then I've picked up various diamond blades for 4-1/2 grinder.
Hilti, Bosch & Dewalt.
My experience with concrete abrasive blades has been disappointing.
The blades wear quickly, cut depth thus varies and I wound up making
multiple passes (with multiple blades) to get a consistent cut depth.
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