Changing structure required professional input, you need to hire civil eng/consultant with PE and able to calculate and sign in order to proceed with your request unless anyone in Lowyat able to guaranty your structure stability once you modify it. They will consider all the cantilevers of the support, where is the piling and pile caps where is safe are how thick is the beam, concrete grade, soil settlement for that extension. (soil test to check soil quality only developers know normally they won't share to outsiders) RC wall is more expansive to cast compared to a brick wall, there are there for a reason you can compromise the safety factor by asking your own contractor to hack them.

Remember you and your family or someone's family is staying inside your building and you are responsible for their safety.

Anyway at this stage, you can ask the subcon of the developer if they can help you pile some point at the extension area by paying them some side earn then after they handover the developer you filly take over then you can expose the piles and make new pile caps then connect to existing beam to ensure the beam will settle with the whole building and will prevent crack.

This post has been edited by ianlti: Jun 30 2021, 12:17 PM

As long as you got the money and the developer allows without void your warranty then is fine and no complaint by your neighbor.

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