Rafael,

Your English is understood, as is your Spanish [:)]
However, this forum is English-only, so please don't post translations here. The "other languages" section is monitored as well, and questions in Spanish get an answer too.

Many, many people have asked for a way to construct second floors. Although not officially announced, it is very probable that in a not too distant future such a feature will be implemented.

Que tengas buena noche!

Hans (para ti: Juan)