O3.1 (and I know this isn't RB, but still), states that rubble outside the printed rubble depiction doesn't count. So given that, the question is does the building exist on either side of the LOS line? Hard to tell from your pic. I would be inclined to call that a full blockage, i.e. that the building depiction exists under that extra bit of rubble depiction. But I'm sure someone would argue just as effectively against, and were I at the table, I could probably be swayed.
The LOS touches the building outer black line. There is a tiny, tiny bit of black to the RHS of the red line just below the "3". No more than a handful of pixels, to be sure, but still there. The rubble only starts inside the lower loop of the "3".
That is true, but you wouldn't be able to bypass R63 along the R62 hexside anyways. With this closer view, I would definitely say that the building depiction goes right to the hexside, any rubble outside R62 is (for this purpose) is a small portion extending across the hexside into an adjacent non-rubble location, and is ignored per O3.1. No LOS.
If you are talking about the rubble strand in R63, then level 1.5, same as the building. If you are talking R62, then it's a 1/2 level LOS obstacle. Remember, rubble depicted outside the rubble hex has no effect whatsoever in the rules.
To continue, if you are talking about the small part of the building depiction in the rubble hex, that is ignored as rubble exist throughout the entire hex and is a 1/2 level obstruction to LOS as CTKnudsen intimated.