RFC: Breaking up concrete floor

You can chain drill with a masonry drillbit, and then break out the remains with a chisel.

Don't let the dust keep you away from POWER tools...A simple sheet plastic enclosure and a good shop vac can take care of it. Just suck up as much as possible AS it is being created with saw, drill, or whatever.

Your slab is most likely 4" or a bit less...A circular saw and Diamond blade would do 90% of the work cutting a nice hole with good edges, then bash the rest out with whatever you have.....

In my house (built 1927), the floor is less than a couple inches thick.

Well, not for all of it anyway. I'd use a diamond blade in a circular saw that you don't mind discarding. One of the best discoveries I made last summer while doing a bunch of granite and concrete work on my house was the $15.00 diamond blade made by DeWalt for 7 1/4" circular saws (found at Home Depot in the power tool department, but located a long way from the Hilti $80 blades). Cuts granite and concrete like butter.

I don't see any way around the dust unless you're willing to use a wet saw and flood the basement with water. Back to square one, I guess.

Good luck on this. The first project I did last spring was to trench around my house (more of a covered moat, really) and run drainpipe from that and the downspouts to the alley. Since then I've been hoping for really good rain and snow, but we haven't gotten that much moisture yet (St. Paul, MN).

Pete

Core drill the corners and score the concrete in between with a diamond blade.

Whilst doing anything that creates concreate dust in computer rooms or telephone offices its standard practice to have someone poking the buisness end of a shop vac equiped with a HEPA filter right next to the saw blade/drill bit/whatever. It works perfectly, ALL the dust ends up in the vac,

-Howard.

Be careful not to get too close to the wall, otherwise you're likely to run into the poured concrete footings. Six or eight inches is about right, and this should give you clearance to make outline cuts using a wetsaw, then hack it out with a hammer and chisel or a jackhammer (keep everything wet and you won't create any dust).

Have you considered how water is going to enter the sump, and how you're going to line the sump?

Harry C.

Is the belief that you _need_ to do it based on previous springs being wet in the basement, or just "omygodtheresfivefeetofsnowintheyard!"??

If you have not needed a sump before, I doubt you need one now, just because there's a lot of snow out there...it has a lot more to do with the drainage around the house than the snow depth.

Stay 8 inches away from the walls, at least, and beware of undermining the footings. A hammer drill can make a lot of connect-the-dot holes in very short order, unless you have a grade of concrete I'd be surprised to find in a residential basement from 1959. With the holes closely spaced, a chisel will connect the dots nicely.

I have done this without the chisel. Drill the holes, and provide one whack of a sledge in the center of the circle. Pick out the pieces.

Kevin Gallimore

Do you have access to several pounds of powered iron and powdered aluminum?

How about 500 lbs of sandbags and hummmmm....2 lbs of PETN?

The only other feasable way that I can think of at the moment, is a decent SDI hammer drill, a couple 5/8" bits and a good cold chisel.

drill a series of holes, 1" apart around the periphery of the hole you want, then hit the inbetween sections with your cold chisel...or drill more holes at a diagnel and wallop the snot out of it with a sledge hammer. This usuall breaks the 'crete along the lines of the holes.

Gunner

The two highest achievements of the human mind are the twin concepts of "loyalty" and "duty." Whenever these twin concepts fall into disrepute -- get out of there fast! You may possibly save yourself, but it is too late to save that society. It is doomed. " Lazarus Long

BFH Gerry :-)} London, Canada

I have made several holes in concrete using an air hammer. One was through 12 inches of wall and another was in a floor to install a pipe for coating fishing rod blanks. The dust is not too bad with a relatively puny air hammer, but you could install polyethylene to contain the dust as they do when removing asbestos. You shouldn't need to go the whole nine yards and have a negative pressure in the containment area.

Dan

A plumber had to break the slab under the apartment I once rented to get to a leak. He had a nifty small electric jackhammer, was noisy but didn't make a whole lot of dust, mostly chips. Was almost a one-handed gizmo, worked great for the 2-3 inches of concrete he had to bust. You could probably rent one or HF has them in the catalog semi-cheap. I've done the chain drilling bit, it leaves a lot of dust and you still have to bust the webs out.

Stan

Yep. I'm going to use a prefab sump.

-Carl

There's been some changes to the surrounding area that affected the drainage of the entire neighborhood with the results that the basement floods after a hard rain or a quick snowmelt.

That's what I'm going to do.

-Carl

Just wet the area down (soppy wet) where you're going to hammer, and there won't be any dust. Sandbags, or just rolled towels since this shouldn't take long, will keep the water from spreading to places you don't want it.

Gary