The balcony beams are not designed with brick works load although they possibly can take the extras. There are other issues like excessive stress may affect the water tightness performance of the concrete flat roof, the proposed works may damage the water proofing, etc. Some light weight block works maybe a good choice here. Get the engineer of your renovation works to advise you. If you don't have one, engage one to look at this issue for you.

This post has been edited by concretemad: Mar 13 2017, 10:14 PM