Mmmh,didnt know we had structural Engineers as members of SK
@Tito,what do you mean that the beams too have to be made by Clayworks,thats CRAP,the beams are cast insitu,all you need to know are the hollow block dimensions and loading regime i.e what kind of load are you going to subject the suspended slab to.
If you geeky enough,try going through BS 8110:1 1997 clause 3.6. Good luck.