In that case you are in category 3 and have a boundary condition. You may not need to protect the whole roof, but just the section adjacent to the boundary. I am not sure what your local standards are, but I would have thought they ought to stipulate a minimum stand-off.
With a thin deck you...
If you don’t mind me asking, why do you need to protect the roof? In the UK you would only do so in four circumstances. 1. The roof behaves as a floor. 2. That part of the roof is a means of escape, say for maintenance staff. 3. A local boundary condition exists i.e. fire may spread to an...
There are some good options listed above; here are a couple of alternatives to explore. If there is sufficient stiffness to provide lateral confinement you could use vibrated stone columns to increase the general stiffness of the ground. If the soil is suitable it can be cheaper than piles. If...
There is an old form of construction, known as a pencheck stair, which can be used to support a stair from a masonry wall without columns. Such stairs appear to ‘cantilever’, but as inferred by the original question, they do not do so. Pencheck stairs work by combined bearing and torsion and...