Been there. Worst plumbing job I had was when I replaced cast iron
DWV in a laundromat w/concrete floor. Had to dig a ditch. Hired a
helper and used two jackhammers. Couldn't fool around - had to get
the job done.
A 90 lb hammer is definitely faster, because you ain't taking a 3x3
foot slab out in one piece, anyway. The hammer on the concrete,
and acetylene on the rebar. There is going to be dust. Wet saw will
minimize the airborne dust, but will make much mud. Very messy,
and worse to clean up.
Yes, they should hang dust curtains and use positive ventilation.
This keeps the mess in the work area.
Of course, you could chisel it out by hand... ;->
If this structure was built as a residence then I will bet that the floor is
4 inches max. Last time my plumbing leaked under the floor I got some fiber
and diamond blades for my "crappy" circular saw. I call it crappy cause I
only use it for crappy jobs. Kept the area damp which helped hold down the
dust. Took most of Saturday to get though enough that the 16 pound sledge
could do the rest.
Any way you go there is going to be a mess.
I cut a trench in my house to house an electrical conduit to service an
outlet in the middle of the room. I built a small dust partition using
2x4's and visqueen that covered up the immediate area to be cut. I cut a
slit in the visqueen for my hand and put the circular saw inside this
"house" if you will. It was slow going and needless to say, quite a bit of
dust still escaped. Overall however, I think I did reduce the dust by a
significant amount. I let it all settle and then gave the room a good
clean up. Not sure if you can do the same but rather than dragging an oil
leaking, noisy, heavy jackhammer in, I'd sure consider cutting with a dry
I am exploring cutting a 36"x36" hole through the 8" concrete slab in my
kitchen to access a sewer line for repair.
Called a few concrete contractors and one told me he will use a jackhammer
to punch the hole (cost $300) and the other told me he will use a saw (cost
$500). The jackhammer will probably spray dust in all directions and shake
loose some copper pipes in walls. The saw will make a clean cut according
to the contractor but he told me "imagine starting a motor cycle immersed in
a mud puddle"...this does not sound promising. Is there a way to do this to
minimize dust and mess? I am willing to pay a bit more for a cleaner
Also, if they use a saw, does it mean it is a big mean machine they will
move from my door to the kitchen and along the way it may scratch the tiles
along it's path?
Not saying this is good but it's better than nothin'. When I sanded
my parquet floors, I put an old 21? inch fan in the window, and left
it running all the time, including after I stopped. The goal was to
get the air out before the dust settled. About an hour after I
finished, the fan "sputtered" to a stop, never to work again. Worked
(Another time I was trying to fix a 4HP outboard motor, in the
bathtub. Put a 21? inch fan in the window and a big fan in the
doorway, both blowing in the same direction of course. It still only
took 20 seconds for the room to fill with smoke, but that was better
than the 10 seconds I got otherwise.)
If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.
Neither sounds like a good option. The saw will be a neater cut, but still
a mess. Are you sure it is 8" thick? If it is less, like 3 or 4", you can
score the outside perimeter with a circular saw and abrasive blade and then
break out the center. Heavy hard work though, but a little more
controllable on the dust flying compared tot he big machines. Still a mess.
I had my basement floor sawed. He sprayed the whole damn basement.
WTF? he could have used a drop cloth or somethin. Eventually discovered
the stuff was in the furnace and causing it to not function as well.
What a mess. And even after they use the saw, they will probably have
to jack hammer a bit to get the concrete out anyway. And those clean
cuts don't heal as well, at least in my case.
However, the cleanliness will depend on the quality/self-respect of the
people you hire no doubt.
On Thu, 28 Jul 2005 02:35:10 -0400, meirman
An oxygen - iron "burning bar" torch will melt concrete. This was one
way of cutting marble in a quarry. You can see one in action by
renting the old James Caan Movie "Thief". It probably creates more
problems than mere "dust" however.
Make sure its that thick... If its only 4" you can do it all yourself.
Get a drill and verify the thickness. 8" thick, get someone else to
go at it. 4" will only take a few hours and is a good workout.
I broke up my basement floor to put in sewer lines. Not a bad job.
If you want a real clean cut.....
Use a circular saw with an abrasive blade (get two they are cheap)
Put up plastic liners around all the openings and open the window.
A nice fan will be ok in the window
Score it and cut a little bit in, This will give you a nice clean line.
Use a sledge hammer or something similar to break it up.
If you want to make it even nices, drill holes all the way through in
a sort of grid pattern. When you break it up, the cracks will form
from those lines.
If you want to check the thickness you can drill a hole through the sab
with a masonry bit. A metal detecting stud finder would probably find
rebar. If not rebar, it might have steel mesh (probably not the right
word) maybe #12 wire on 6" centers at 90° with welded crossings.
Sorry, those are in the weapons of mass destruction catagory; i.e.,
dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at
Yes, there is, it is called a plasma torch. About 10 feet long with intense
flames coming out the end. It is used in demolition to slice through
concrete and steel. Not much good for a 3 foot square in the middle of a
finished room though!