Bricks, Masonry, Asphalt and Concrete - Size of old concrete fill?

I am building a garage. The area currently has a lot of concrete that needs busted up. I was told to just bust it up and leave in the area as fill. The question I have is how big (maximum) should these pieces be? I took sledge to one area and it broke in pretty big pieces. I would think that if they are too big, it wouldn't be good. So what is too big?

Bill

Hello again Hammerash.

Based on what I've read about concrete work I'm pretty sure this is a bad idea. Ideally you want several inches of sand or crushed rock compacted in layers of a few inches each. There is just going to be no way broken concrete chunks can be "compacted" so as to be stable over time.

I probably should have mentioned that I need over 4 foot of fill on the one side! The inspector said OK to use it and so did some concrete guys when they came to look at job. I forgot to ask them how big it should be and I have yet to find someone to do the job. It is a tough job-mainly due to the entrance way into house where underpinning may have to be done since there is also access to basement. Lot of them don't do underpinning. So still think bad idea when I need that much fill!

Bill

If it were my house I would not do it, I would fill the first couple of feet with soil compacted in layers, then finish with crushed rock compacted in layers, so that I KNOW positively that a firm proper compacted fill job lies under the foundation of my house.

Unless I stood to save a very substantial amount of money, I would not consider using the concrete as fill under my foundation. Perhaps you need some fill material elsewhere, not under a foundation?