ᐅ 150 kg/m² live load for garage roof with option to convert into a roof terrace?

Hello,

From the beginning, we informed the architect that we wanted to keep the option open to use the solid garage roof as a rooftop terrace.

Now that the house construction is about to start, he told me that the garage was only designed for 150 kg/m² (31 lbs/ft²), while a proper rooftop terrace should be designed for 400 kg/m² (82 lbs/ft²). He also mentioned that he has no concerns about the 150 kg/m² (31 lbs/ft²) load, since the intermediate floor in the house is designed for the same load, and the total roof load capacity should be considered...

70 m² (750 ft²) x 150 kg/m² (31 lbs/ft²) = 10,500 kg (23,150 lbs) = 10.5 tons

Of course, that sounds like a lot at first. That would be about the weight of 8 cars. Still, I have some concerns.

I would be interested to hear your opinions.

Best regards,
Judyyy