That's not a "no" then. That's a statement of fact.
Almost every loft conversion requires new timbers for a floor. How that is done, and how height is dealt with is all down to the designer. There is no height restriction for loft rooms either.
I never said it was a no meaning it couldn't be done, I was saying it was a no in its current form which is what my neighbors have done. You couldn't install a steel or install new timbers without us noticing.