OT: cutting concrete foundation

[Marc Hills]

A rather urgent need to replace my oil tank requires that I install an exterior bulkhead cellar door to my home. I'm doing this project myself. I've dug the hole and poured the concrete footings, but now I'm faced with how best to open up the foundation itself. Above grade are cinderblocks, which I'm not worried about. Below grade it is poured concrete, I'm estimating 9 to 10 inches thick.

My first inclination was to rent a gas powered concrete saw, but it only has a 4 1/2" depth of cut. I'd have to cut from both sides, and therein lies the problem. One end of my existing oil tank is in the way on one side of the planned opening, and an interior (non-load bearing) wall is right up where the other side of the opening will be. There's no room to get the saw in there for the interior cuts.

Is it possible to drill a series of holes through the foundation wall with a hammer drill and knock out sections with a sledge? If so, is it advisable?

Any help would be very much appreciated.

[Don Abele]

Marc, first how is leaf peeping going? Should be getting into full swing there shortly. I miss living there (spent 3 years in Sanford). Beautiful state.

I've never tackled anything like you are describing, but have seen it done - and it's never been by a DIY'er. This is a pretty big project, considering the thickness of the concrete. I've used hammer drills before but none to drill through 9-10 inches and the entire size of a doorway. That's a lot of holes :eek: .

Have you talked to a contractor to get an estimate to cut the hole for you? A friend of mine had it done in Washington State a couple of years ago and they used a 14 inch saw (maxes out at 10 inches) and it cost him about $500 for it. They were in and out in about 2 hours.

Let us know how it goes.

Be well,

Doc

[Marc Hills]

Hey Don,

I'm always caught off guard by how early "peak foliage" comes, even after living in Maine for 17 years. I imagine northern Maine must be about peak now and we're a couple of weeks behind here in Portland. A maple in my back yard is absolutely ablaze in red, especially in the slanting light of late afternoon.

I agree that subcontracting out the job is clearly the sane alternative, and unfortunately one that is not possible. I'm still scrambling to come up with the money to pay for the new oil tank. I've got to find a way to get through that foundation myself, by any means necessary.

The gas powered concrete saw I looked into is one with a 14" blade, but with the arbor, shield, etc, it still only yeilds a 4 1/2" to 5" depth of cut; coming at it from both sides is how they get the 10" maximum cut.

I'm beginning to think I need to figure out a way of moving the oil tank without disconnecting my furnace's fuel source, and knocking out that interior wall. If anyone has any other creative ideas, I'm open to anything (within reason) :)

[Dan Mages]

How do you eat an elephant?? In very very small pieces.... ;)

Clean it out and chop up the old tank.

Dan

[Chris Padilla]

This Old House had an episode where such a large chunk of foundation was chopped out. The guy had a VERY LARGE circular saw on a frame that allowed controlled movement. I think it is a pro job...not DIY.

[Steve Jenkins]

How big is the area that you need to cut through the concrete. Itcan be done with a rotary hammer and drill bits then beat the heck out of things with a sledge. How much time do you have? If the money isn't there to hire it out then it's a matter of getting started and not thinking about the hours as they go by. I installed a downdraft stove vent for the kitchen and had to put an 11" hole through the foundation same thickness. I spent about 4 hours under the house and another couple outside. Luckily I didn't hit any rebar. Of course working where you have room will make things easier and faster. steve

[Marc Hills]

How much time do you have? If the money isn't there to hire it out then it's a matter of getting started and not thinking about the hours as they go by.

Steve:

That's how I did all the digging. Me, a shovel and a wheel barrow. I'd like to say that I have more time than money. But the truth is, I just don't have the money.

[Don Abele]

Marc, my house in Sanford had the oil tank located under the main part of the house. I moved it into the garage (walk-out basement). I'm not recommending or condoning what I did - but this is how I handled it.

I disconnected the fill and vent pipes through the wall and then from the top of the tank. I then disconnected the oil line to the furnance. Depending on how much play you have in that copper pipe, you may not even have to disconnect, just be sure you don't kink the pipe. It's fairly flexible copper.

Here's where things got a little hairy. I built a wheel assembly for the tank. Basically 2 - 2x4's under the legs. The 2x's had wheels mounted on them. I then ran 2 - 2x4 stretchers between them. Basically a 2x4 frame with wheels at the 4 corners. I used a hydraulic floor jack in the center of the tank with a 2x6 to distribute some of the pressure. With two friends holding each side of the tank for balance, I jacked the tank up until I could get the wheel assembly under it (I left 1 stretcher unattached). Attached the stretcher then lowered the tank down on it and then removed the jack (picked it up). Then I just rolled it right out into the garage and repeated the process to get it off.

Hope this helps.

Be well,

Doc

[Charles McKinley]

Hi Marc,

Do you weld? I would demo the old tank with a sawzall then get a new tank in pieces and assemble it inside.

If this is not and option. Break out the area for your header. Put in rebar and pour the cement for the header. Remove a block in the corners of the hole for the door then drill the holes to remove the wall. For the footer itself cut the footer with the saw into chunks that are easier to remove then use an air hammer or hammer drill to clean out the tight corners.

Have you checked codes in your area? I'm dealing with foundation problems here and I have to have stamped drawings for everything then have it inspected when I'm done

Good Luck

[Marc Hills]

Thanks everyone. This is really a godsend to be able to talk this through with like-minded people.


Depending on how much play you have in that copper pipe, you may not even have to disconnect, just be sure you don't kink the pipe. It's fairly flexible copper.

. . . I built a wheel assembly for the tank. . . . Hope this helps.



Don,

That actually does help, at least as far as gaining clearance for a concrete saw for one of the interior cuts. Sometimes I need help visualizing how to do something. Hearing that it has actually been done before helps a lot too. Did you have to switch to kerosene when you moved the tank? Or is your garage heated?

It's beginning to look like I'm going to have to knock out that interior basement wall that butts up to the other side of the planned openning.

Charles:

I don't weld. (Learning is on my "to-do list".) Besides, at least here in Maine, there are environmental abatement issues if you cut up an oil tank. Removal and disposal of the old tank is part of the price I was quoted for the new tank installation. My piece is limited to providing a way in and out of the basement.

And I suspect you are of course correct about the building codes. This is one of those "tis better to beg forgiveness than ask permission" sort of situations.

[Don Abele]

Marc, my garage wasn't heated when I moved the tank. I asked my local supplier and he said it wouldn't be a problem as they had additives in the oil to help it from thickening up. Regardless, I ended up heating the garage when I turned it into my workshop. My neighbor had his tank outside and as far as I know, he never had a problem. Best to check with your supplier though.

The other thing I accomplished with the move was rerouting the line as it was originally buried under the concrete slab. I think it was in 2000 that Maine outlawed buried lines. So I fixed it while I was at it (this was in 1997) since they were already advertising the change.

Maine is not the only state with those abatement programs. Two years ago, my father (lives in NJ) removed his oil tank himself to save the cost of having a company come in and do it. Because he cut it up, the cost for disposal ended up being more than had be hired someone to do it for him. Some things are just better left to the experts.

Best of luck with the move and demo. You need to get cracking - it's getting cold!!! If you have any more questions, please ask.

Be well,

Doc

[Lou Morrissette]

Marc,
I don't know what show it was, but someone was using a concrete chain saw. ( scary looking thing:eek: ). If I remember, the thing had like a 20" bar. I realy don't know if it's something you can rent, but it seemed to cut this guys foundation ok. You might check it out in your local rental stores.
good luck.

[ralph scherrer]

Mark,

There are professional companies out there who also do this work. In general, many use a hydraulic powered "ring saw" which also uses a 14" blade, but the blade is driven around the circumference, not through a hole in the center. That allows the 14" blade to be pushed through the wall up to around 11" or 12". I would get an estimate from someone on what they would charge. If they are too much, a DYI can do it using a rental unit. See if you can find someone who rents a "KANGA Saw". this unit is gas powered and looks like a chainsaw (with a much shorter bar!!) that is used in a plunge cut fashion to start the cut. The nice part about this unit is that it makes a straight cut (as opposed to a radius cut off of a curved blades). I have a local rental here that recomends them for people putting in escape windows in basements.

[Chris Padilla]

Ralph,

That is exactly what the guy on TOH used...couldn't remember the name but "Down Under" kept popping up in my brain for some strange reason!! :D

[Charles McKinley]

Hi Marc,

One other thing, seal up the area on the outside where you are going to cut. The basement is a vacume and the dust will be sucked into the house! DAMHIKT :(

I had forgot about the chainsaw style cement saws. This may be your ticket.

Good luck with the project.

[Don Abele]

Marc, I was looking around the web tonight for that concrete chain saw. Seems that the company that makes them is called ICS. As a matter of a fact, several articles indicate that they are the sole commerical producer of concrete chain saw technology. Also indicated that these are becoming pretty common place. Where are you at in Maine? There's got to be a local rental place nearby that may have one. I did a search for ICS rentals in Maine - here's the list:

WINDHAM RENTAL CENTER, INC.
730 ROOSEVELT TRAIL
WINDHAM, ME 04062
207 892-7743
FAX 207 892-8993
** Parts & Service Available **

TOPSHAM RENTAL
127 MAIN STREET
TOPSHAM, ME 04086
207 798-4546
FAX 207 798-5032

UNITED RENTALS
96 TARGET INDUSTRIAL CIRCLE
BANGOR, ME 04401-5716
207 942-7770
FAX 207 942-7771

TAYLOR RENTAL
6 COMMERCIAL ST.
BIDDEFORD, ME 04005
207 282-5104
FAX 207 284-8344


HTH - Be well,

Doc