How to cut a concrete basement floor?

[Jeff396]

Hi all,

I'm in the process of finishing my basement. I need to cut a trench in the concrete to plumb in a sewage pump and to put in the actual basin. I had though I would rent a concrete saw but all I can find are gas units which would put out too much exhaust. Any other suggestions on how to cut through the floor fairly neatly? I had also thought about a jack hammer but I sure would think scoring the outline first would make a nicer job of it.

Jeff

 

[kenmac]

You can buy a concrete blade for your circular saw. It has worked well for me. Use a mask though, makes alot of dust. For the basin you could use a 1/2" hammer drill with a contrete bit & drill holes around your mark for the basin & break it out with a sledge hammer.

 

[beenthere]

Jeff
I'd be more concerned about the fine dust that gets everywhere, than the fumes (can open windows to get rid of them).

One cheap way I remove dust is to put 20"x20" furnace filters on the intake side of 20" window fans setting near the area being sawn. Draping the area in plastic helps too, but that dust will find ways to get through most anything.

The last one I did when putting a basement toilet in, was just using a maul to break up the concrete. Could get a pretty good edge to concrete against when finishing it up. Some dust and chips of concrete around, but not as bad as a saw will make.

Also, you may get a saw that uses water to keep the dust down, but then getting rid of water may be the reason you are doing this in the first place. /forums/images/graemlins/wink.gif

 

[_RaT_]

If you can do a good job of ventalating the room then a concrete saw would be cheap and fast. You of course would need a wet vac to continually pull out the water. Some concrete sawing companies use hydraulic powered saws on walls, perhaps a call to them might get you some answers.

 

[Deerlope]

Is this an actual sewage pump or a sump pump to get rid of water only. Either way you can rent an electric diamond core drill. There are 12" and bigger core for them. If you buy a diamond blade for you skill saw and just wet the floor that will keep a lot of dust down. Beleive me I have cut a lot of concrete.

 

[Jeff396]

It's an actual sewage pump for a complete bathroom. Not only do I need to make a 20 or so inch hole for the basin but I need about 12 foot of trench to get the plumbing over to the basin.

Jeff

 

[Farmwithjunk]

I'm an estimator for a general contractor. My background prior to moving in to the office was as a carpenter. We do a lot of concrete construction. (parking garages, ect.) I've been on site while concrete sawing was taking place, so I know a little about what makes the most "live-able" conditions.

First off, we can't own the right equipment to saw concrete for what we can rent or sub out the work for. The company we contract cutting and coring with has hydraulic saws with diamond blades. The power unit stays outdoors. The blades are water cooled to also aid in keeping the dust to a minimum.

Their rates are based on thickness of the slab X the legnth of cut.

Sometimes the effort to "do-it-yourself" will lead you to spend too much or make things more difficult than need be. I'd at least call a concrete sawing contractor for a price. You might be suprised.

 

[jim_wilson]

I used an 8.5 inch Skilsaw with a diamond blade in it to cut thru my foundation wall when I wanted to add a wider door into my basement. It DOES make a lot of dust though. The hardest part of getting thru the concrete in the floor is getting started. A couple of years ago I also had to do a similar thing to what you are talking about - except I needed a trench across the basement from front to back to put a sewer hookup in. I ended up just using a sledghammer to break thru the concrete as I dug the trench across the floor. The concrete on my floor was only about 3-4 inches thick though - if your floor is 5-6 inches thick this probably would not work for you. You can rent core drills at Taylor Rental centers - or you can use a rotating combination hammerdrill to put some holes into the slab then use a sledge to break a piece out to get started on your trench. Just pounding on the slab will not do a good job of breaking thru - if you can get started however and then dig the dirt out underneath the slab some you might be surprised how easily a sledgehammer will break up the concrete.

 

[Jeff396]

Thanks all! I'm going to give a couple of these suggestions a try tomorrow. The slab is about 4" thick as I drilled a couple of 3/4" holes thinking I would try outlining with the hammer drill and then break it up. That wasn't practical as it took soooooooo long to get just one hole made. Will report back on how it goes.

Jeff

 

[gotrocks]

Jeff,
I have used a DRY CUT Diamond blade on my portable hand saw.
To keep dust down I have turned on the hose to a slow trickle and let it flow into the cut. The last trough I cut was kept straight by laying a 2x4 down as a guide,
that way you don't have to worry about loosing your chalk line mark.

Yes I know and hope you do know the <font color="red"> danger of electrical shock </font> . /forums/images/graemlins/blush.gif
I,ve done this a few times without a problem. As far as shock, I have had more problems while working outside after a hard rain and having the plug fall into a wet spot.
If you don't like the wet version, then get a good shop vac and have someone move the hose along in front of your cut, that will get the majority of the dust.
Good luck and Happy Holidays!