OT: Some concrete leads

[pingu]

No, the concrete - if it's nice and runny (but not so runny that it runs past the foam) - should find its own level.

If you want a really nice job then you could first make a platform of concrete by relying on the concrete to find its level. Once it has set, take off the planking and attach fresh 4" high planking (or whatever, depending on high thick you want the second concrete layer to be) to the side of the concrete using Rawplugs etc.

Then pour a second layer of concrete over the first layer and tamp the second layer down, using the new planking as a guide, to get a nice flat surface. Job done.

[Ross]

"No, the concrete - if it's nice and runny (but not so runny that it runs past the foam) - should find its own level."

It's this sort of method that likely got him the surface he has.
Either form it correctly, pour on top and finish, assuming it's clean and rough enough to stay put. Or sleepers, either scribed or shimmed as Paul says.
A glass(any) structure on a Mickey Mouse foundation is just asking for it.
If it is attatched to the existing structure it should also have some foundation below the frost line to prvent the addition from moving independantly of the house.
If you put it on a pad it shouldn't be attatched to the house as it will move around more than the house.

[whiskychaser]

Thanks for the replies and suggestions! I tried to take some pics but they dont show the levels clearly so there is no point posting them. Just to clear a couple of points though: The land that belongs to the house isnt very big and its all concreted over. The old greenhouse didnt sit on its own pad, it sat on a 'flat bit' of that. The new one is much bigger so wont fit on it.
My latest idea is to put down a bead of cement and lay the frame into it. I'd then make sure the frame is level and let it set. I could then fill the centre at one go and be able to tamp down and level it using a plank across the tops of the frame sides. Anyone want to shoot me down in flames?

[Tiger]

Similar to what I said... my way is safer and more true level. Remember... glass will crack under stress of unlevel foundation.

[Ross]

I think what you are describing is forming atop the old pad which has been suggested. Someone else made the suggestion of sand and blocks for a floor which I like.

[whiskychaser]

I think what you are describing is forming atop the old pad which has been suggested. Someone else made the suggestion of sand and blocks for a floor which I like.

Because of how the threads get mixed up I'm not entirely sure what was said when. What I DO know is I got a tranny problem on the way home. My younger son tells me he's got fuel dripping from underneath his car. Am I going to be busy this weekend or what?

[pingu]

Well the concrete that they were using on the Burj Dubai (or whatever it's called - the tallest building in the world) had that consistency so it can't be all bad!