Thanks to all for the good advice. You all agree that the priority is
to have the antenna on the clear.
To summarize , I would exclude the option to elevate the antenna
because I do not like to walk on roofs or climb towers any more, a
ground level antenna is much more safe.
About the ground radials, my understanding is that the RF current
flowing in to the antenna from one terminal of the feed line, must
return to the second terminal of the feed line that is grounded at the
antenna base, and it will do so flowing through the soil in the
vicinity of the antenna. If I provide a more conductive path on the
soil by laying radials, the electrons will find it, regardless of the
simmetry of the system and avoid to dissipate energy heating up the
ground.
On the other hand, a building near the antenna is not connected to the
second terminal of my feed line and so the RF current captured by the
building metallic structures can only be dissipated and playing funny
games with the electronics gadgets inside the building.
Now that I decided to put up a new antenna, let's just hope the solar
cycle 24 will behave.


Thanks to all
Giovanni
IZ0SQZ