Wondering if you can help me out.
I'm planning on building a small single skin thermalite block, skillion roofed outbuilding, (5.7m x 2.8m and 2.4 high) over and around a slab already present.
There was once a pre fab type garage here apparently - they knocked it down not long before we bought the place; I can't find any details or pictures of it, although the outline does show on old maps and the overhead documents in the deeds.
The concrete base itself is lined on one side and one end by a number of large retaining blocks (around 3x1 ft each). The other side is abutted to a concrete garden pathway at the same level.
I've excavated the soil around the retaining blocks to around 400mm deep & 450mm wide, and loosened them to see what is what, as these are not flush with the slab and a hindrance to building.
So I'm thinking of trench filling with concrete up to meet the level of the original slab, then building the block work from here.
The questions are :
1. Will I need rebar or Could I lay the retaining blocks in the ttrench (they are very heavy and solid) and concrete over them?
2. Would pouring against an old slab be problematic?
3.where ideally should the block work begin, below ground level, or level with it? Or above?
Hope you can help.
Many thanks in advance.
Cheers