Is there a way to cut through concrete slab without making a mess?

[~^Johnny^~]

[meirman]

In alt.home.repair on 28 Jul 2005 09:18:35 -0700 [e-mail] posted:

Don't worry about the ceiling and the roof. They can go right through that. (You can patch it later.)

Meirman

-- If emailing, please let me know whether or not you are posting the same letter. Change domain to erols.com, if necessary.

[miamicuse]

Well, initially I was going to tunnel, but then many suggested tunneling may compromise the foundation and footing, so now I am thinking fixing it from above, but if it will create a mud pond and damage my cabinets, I did not consider the issue of settling, are you saying the weight will crack the new PVC pipe? Can I not put sand and compact it before I pour concrete? I don't know how deep the pipe is though... is this a real concern?

MC

[anoldfart2]

Heck, if that's the case, just contact Osama and tell him to drop a bomb in your kitchen :)

[RicodJour]

If you're in FL (likely with that monniker) and you have an 8" thick slab, you may have a post-tensioned slab. You do NOT want to go cutting into that slab willy-nilly.

This from a post a few years ago by DanC:

Dan Jul 2 2003, 2:13 pm show options Newsgroups: alt.building.construction From: "Dan" - Find messages by this author Date: Wed, 2 Jul 2003 11:27:07 -0700

You damn well better believe there's a reason NOT TO CUT OR DRILL! Depending on the design specs, PT cables can have as little as a few hundred pounds of tension on them or as much as hundreds of thousands of pounds of tension on them. PT cables are as inherent to the structural strength of the slab as is the concrete. While you 'MAY' not see a catastrophic failure by accidentally cutting a single cable, you will suffer some design deficiency that may eventually lead to catastrophic failure. Think of that cable as a big rubber band that's stretched to about maximum and then cut. What happens to the rubber band, other then it's cut? Uncontrolled release of energy! If you've ever seen those 40~ 80 foot post tensioned concrete beams being transported down the highways, you'll notice they usually have camber in them. (Humped up) Your slab is much the same way. It's a somewhat common practice in multi storied structural steel framed buildings utilizing pan slabs.

Were this my house, those doing the work would get & have an engineered design drawing detailing EXACTLY the procedures required to undertake this. None of that freelance BS and shoot from the hip. You haven't lived till you've seen a slab or beam blow apart while undergoing PT. Can you say concrete missiles? (although it is rare)

[miamicuse]

Jez you guys are brutal...

MC

[anoldfart2]

You never yet said what is wrong with the sewer????

[wayne]

here is information on different type of sawing

The Wire cutting is something that COULD be really good for your application if they can drill a hole in 2 places and get the wire threaded it will be cutting from the bottom this will meal all the dust and mess will be in the hole rather than the kitchen.

Normally when cutting concrete the "wet" method is used where there is a steady stream of water on the blade this provides cooling lubrication and debris removal. You should be able to have plastic put down on all of the surfaces and the doorways were well as above depending on the working room they may be able to tent the work area one of the big things 2 is air pressure.if they reduce the air pressure with a fan running outside in the work area the dust will not be able to get very far.

Ask to speak to people who have had the company make holes in their houses to get an idea of the mess

CTI pioneered the use of the diamond cutting techniques shown below. While each has its own unique advantages, all share an ability to provide fast, clean and non-destructive removal of virtually any construction material. If your project requires surgical precision, a cost-effective alternative, or innovative engineering in sensitive environments, CTI's cutting and coring techniques are your only choice.

DIAMOND WIRE SAWING

A motorized system of drive and guide wheels pulls a diamond-encrusted wire around - and ultimately through - the object being cut. To cut voids from a larger structure, pilot holes are first drilled into the structure at the ends of each cutting plane. The wire is then fed through the holes to create the loop that will sever the spoils from the remaining form.

Typical Materials Cut:

Heavily-reinforced concrete, solid stainless steel and rock.

Cut Sizes:

Limitless dimensions and volume.

Typical Cutting Applications:

Crossovers in extremely thick structures.

Demolition of mass-concrete forms such as dams, towers, piers and nuclear facilities.

Cutting of structures under water or otherwise inaccessible.

Cutting of fixtures with complex, irregular shapes.

Advantages:

Precise cuts with no over-cutting at corners and smooth finished surfaces.

Lack of vibration, noise, dust and flying debris enables "clean" demolition in sensitive and occupied areas.

Controlled cutting leaves remaining structures safely intact.

Quick, versatile, safe and economical alternative to conventional demolition.

BLADE SAWING

Depending on the need, circular, diamond-tipped blades are mounted onto a range of power units - from walk-behind slab saws for cutting level surfaces, to track-mounted wall saws for cutting steep or vertical inclines, or even handheld units for smaller cuts.

Typical Materials Cut:

Steel-reinforced concrete, pre-cast concrete, asphalt, stone walls and cobblestone street beds.

Cut Sizes:

Up to 30" deep

Typical Cutting Applications:

Paved surfaces such as roads, runways and bridge decks.

Walls and suspended slabs such as floors and roofs.

Access-way breakthroughs for stairways, elevators, windows and doors.

Trenching and crossovers for mechanical services and cabling.

Advantages:

Precise cuts with smooth finished surfaces

Quick setup and sawing minimizes down time and traffic disruptions.

Variety of power sources to accommodate all available power and exhaust requirements.

Cutting in confined spaces.

snipped-for-privacy@> >

[miamicuse]

Is there a way to make sure it's not PT slab? It's a single story single family residence, probably unlikely to be PT?

MC

[miamicuse]

Wayne:

Thanks, I called about ten concrete contractors and most use the wet saw. Cannot find anyone who will do the wire cutting, and someone else suggested drilling holes at short interval then chisel out by hand may also minimize dust, can't find anyone to do that either. May be this is a too specialized and require some high tech contractors? Can't seem to find them if you know of a link to find such contractors please let me know. Thanks in advance,

MC

[Dennis Turner]

I had a couple of leaks under the slab repaired in my previous home. My plumber brought a jackhammer and chopped out the hole needed himself in just a few minutes time. Of course, we're talking about holes that are somewhat smaller than your 36x36. I replaced the dirt, compacted it to the best of my ability, and poured ready mix in to patch up the holes. Then I replaced the broken ceramic tiles and grouted them. No problems at all after several years. One leak was in the kitchen and the other in the downstairs half bath.

[CL (dnoyeB) Gilbert]

i had plumbers in my house yesterday. They used jackhammer. Again the jackhammer proves much cleaner than the saw.

[smart guy]

Ok, this worked for me, no dust whatsoever. First step was to drill lots of holes all the way down the slab to the size I needed to dig out while using a bag vacuum cleaner to suck up the dust from each hole. Then I strongly and securely gaffa taped a piece of MDF board to the ground with a square opening 3 inches bigger on each side than the hole I had to dig out. I only put the gaffa tape around the MDF cut out to make sure it would be easy to take off. Then with good double sided tape I stuck strong clear plastic on the board, 4 inches bigger than the board. Then I made a square bag out of strong clear plastic by double taping it strongly on the one side. I stuck the bottom piece of plastic to the square bag I made making sure there were no air leaks for dust to escape (I used a lot of tape). I put the jack hammer inside my bag and gaffa taped the top plastic all around the jack hammer making sure the vents weren't covered so it wouldn't overheat. I was very careful not to drop it and make holes in the plastic. I then made a hole in the plastic, closer to the bottom, not too high and gaffa taped a rubber kitchen washing glove to the hole so I could use it to take out the rubble from the hole. I had enough space around the bag to dump the rubble. The plastic is clear so for a while you will see clearly through it enough to make an impact on the cement already weakened by the drilled holes. Eventually you can't see through the plastic anymore because of the dust so you need to make every second count. If there is too much dust, let it rest and start again. It worked for me. All I did after was pull all the rubble away from the opening of the hole, let the dust settle, and slowly peel the MDF off the floor by turning the MDF board clockwise, being very carefull not to drop to many particles on the floor. If you do it slowly and patiently you will have no problems. Forgot to mention, once the MDF is no longer stuck to the floor slide another piece of MDF board under it to prevent anything falling out when carrying the whole lot out side. the only thing I would do differently is take the Jackhammer out before picking the whole lot up onto a wheel barrow. Two of us picked it up anyway but it was heavy. I would also add another bag to the side of the main bag to put all the rubble in. Would have made things easier.