I have a house I'm selling. I have to remove the front half of a garage, and turn the back half into a shed (new front wall with no garage door), because way back before the county kept records, someone built that garage on top of the septic tank. And, the cleanout.
Obviously, I won't be using a jackhammer - I want to remove the slab, not the top of the tank.
The slab sits on top of about 6" of fill, which is on top of the tank. I don't have a real good read on how thick the slab is, but I'm figuring on a 6" average.
My plan is to dig out the fill starting on one edge, and break the concrete as I go...if it cooperates. I figure once the slab is "floating" over empty space, I should be OK with a 10# sledge to bust it off and drag it out, without sending shocks into the tank lid. If it doesn't cooperate, I can rent a concrete cutter (circular saw) to try and score some snap marks into the concrete.
Anyone have any other ideas? Anyone done this before? Anyone bored, near Maryland, and want to come lend a hand?
If you a sure about the 6" of fill a jack hammer should work just fine. I would start out using a concrete saw to cut a kerf in the slab along where you want to save it. Then start at an outer corner. Don't try to hammer all the way through the slab just follow the cracks and knock off small chunks. If you try to take too much at a time the bit will get stuck. I would also have a spare bit just in case one does get stuck you can use the spare to get it out.
When I was 18/19 I spent 12 to 14 hours a day doing that sort of thing.
Think about the problem a different way. Would it be easier and cheaper to just put in a new septic tank in the yard somewhere? Demoing half a garage sounds like an expensive thing to do with all manor of things that could go wrong.
1. no replacement tank because everything is so freakin' wet right now, nothing will perc.
2. there IS a cleanout in the garage. It's illegal according to current code, to have a building on top of a tank. Septic, from what I and the county can tell, went in in '61. The building looks to be of a similar age.
3. Demo won't be expensive, nor difficult. Cinderblock side walls, stickbuilt roof trusses. Chainsaw the roofing between trusses and remove them one by one, then simply tip (or disassemble) the cinderblock walls. No electric to worry about in the building, nothing is finished, it's just the shell.
Believe me...I've thought about this 90 ways to Sunday.
Presentation for sale. It will be obvious that "building used to be there" if I just leave the slab. I need every dime I can get out of this house, so it has to look as good as possible. And, I want to avoid raising any inspectors' eyebrows once people contract to buy it. By. The. Book. Can't have anything on top of a tank? Nothing will be on top of the tank.
I checked it out earlier tonight - I only have to cut the building back about 12' to clear everything. 15' wide, 12' deep...180sf is a liveable amount to have to remove and dispose of. Better than I was prepared for - nearly 3x that much. Didn't realize the tank was as small as it is.
A concrete saw should cut whatever rebar is in there. You can make a deep score at the part youíre saving and shallower ones to help break up the rest. One suggestion if you do, consider buying your own blade and renting the saw without a blade. Many rental companies will mic the blade before and after then charge you extra for wear. Last time I rented one I didnít use enough water and wore enough off the blade where I could have bought a new one (cheapo mind you) for the overage they charged me.
Given the base construction of this building...I'll be more than a little surprised if there's any rebar in there.
I probably just jinxed myself, but...that's the impression I get. We shall see. I need to draw out my new wall, and get my materials list together. I plan to build the new wall while still "inside", then once it's built I'll tear down the part that's coming down, expose the new wall, and start removing the slab.
Equity, I tell myself...equity. Cashing out the equity when the place sells....
Won't you need a foundation, not just a 4"slab, beneath the new wall? If so, saw cut a 24" wide path across the garage and dig a 12x12 trench for the foundation. Drill 1/2" holes into the side of the existing slab and pound in one foot pieces of #4 rebar to tie the new in with the old. Then build the new wall and demo the rest. Check local requirements.
lawyer? If it was like that before you got it it should be grandfathered or exempted, for use and sale. If zoning was in before it was installed sue the city or county for letting it transfer to you this way.
Now, because Im selling the house and no inspector will sign off on a situation like this. At least, not without severely dinging my sale price. Access hatch or not, it cannot be under a building. County code.
Before, when I bought the place, nobody knew where it was, so it got an "it works" inspector approval. Now...22 years later...we know where it is, the County knows where it is, and it cannot be lied about or hidden.
I'm a day to build the new front wall, and tear down the portion of building that needs to come down (stick built roof trusses, cinder block sidewalls). Maybe $500 in materials for the new wall (60" exterior double doors, 2x4s, sheathing, siding). And, hopefully, a day to bust up and remove 12' of slab.
Lawyers, and aerobic systems, cost hundreds of times more money.
If I was keeping it, I'd look at a new system for 50k...but I'm selling it. Minimize expense, make it go. It functions fine, just the building can't be there.