Foundation slab over existing concrete?

[Knackers]

Re: Foundation slab over existing concrete?

I was only going on what Dancing bear stated originally..

3 1/2 inch reinforced slab....... & they seemed to think that the ground was compacted b4 the original slab went in. (I was guessing that they probably did it.)

honestly I would do what I stated originally. at Most I would do what christo said & build a reinforced slab on top of original.....

the whole weight of this thing isnt going on to a 1 foot x 1 foot square pad..... its probably 3 meters x 3 meters square.... thats a lot of bearing area if the original slab and the blocks are reinforced then there in no problem

[Breven]

Re: Foundation slab over existing concrete?

I hear you man...I may go a little over kill, You really have to with all the ground shaking out here in California. One thing about the foundation though...you only get a chance to do it once. I don't think its a negative to make it "too sturdy". It will likely hold up either way... I just always like to err on making sure it holds up, because you can't go back and re-do it.

[Knackers]

Re: Foundation slab over existing concrete?

I hear you man...I may go a little over kill, You really have to with all the ground shaking out here in California. One thing about the foundation though...you only get a chance to do it once. I don't think its a negative to make it "too sturdy". It will likely hold up either way... I just always like to err on making sure it holds up, because you can't go back and re-do it.

Yeah fair enough..... I am originally from New Zealand ... I can remember book cases falling on my head in the middle of the night as an earth quake decided to make its presence felt. I have lived in Australia for 30 years & I tend to forget that not all the places in the world are built on stable ground & never shake.

& Yes you are correct there is only one chance to do footings... & I suppose you are right no time like the present to engineer it corectly.

[Frances]

Re: Foundation slab over existing concrete?

For all its worth, I believe Dave's foundation moved slightly, causing cracks in his oven and one of the bricks in the entry to fall out... on the other hand it has to be said that his oven still works beautifully, so when all is said and done, maybe even a shifting foundation doesn't matter that much.

Personally though, looking back on all the work you put into building an, I'd go for the safer foundation.

[Dancing Bear]

Re: Foundation slab over existing concrete?

We've decided on a change of location - we're moving it into the poolhouse that we're building out of what used to be the garage - so it now has a 6" thick, 60 year old slab with no cracks in it, topped with 3" of new reinforced concrete from bringing the floor up to meet the rest of the new deck. I think that's gonna hold OK.

Now we're in the throes of kitchen design. At least I know which corner it goes in so I can start piling up cinderblocks.

Thanks for the help!