good day mate.

answer

1) The ground and 1st floor must follow standard height according to the original development.. must follow the rest of your neighbor standard unit height
2) The new floor ( 2nd floor or 3storey ) can adjust to a maximum 3500mm height -2nd floor slab to top of roof beam level ......
3) Total height must not exceed 12 meter from ground floor level up to highest pitch roof level.... (must inlcude top of roof level)
4) Requirements- need to prepare drawings to the following department and get approval
a) approval plan building control department  (JKB)
b) approval plan town planning department (JPRB)
c) approval plan engineering department

hope this answer your question

cheers mate
Izwan
www.archidstudio.com

I've done it for 1st floor front (higher than existing/neighbour) but never tried ground floor.
Ìf house at DBKL, >10 years, end lot and rebuilding front with extension, you should have a fair chance.
Duplex or loft is doable but you lose plenty of space unless you don't mind or your lot is big/long.

good day mate.

answer

1) The ground and 1st floor must follow standard height according to the original development.. must follow the rest of your neighbor standard unit height
2) The new floor ( 2nd floor or 3storey ) can adjust to a maximum 3500mm height -2nd floor slab to top of roof beam level ......
3) Total height must not exceed 12 meter from ground floor level up to highest pitch roof level.... (must inlcude top of roof level)
4) Requirements- need to prepare drawings to the following department and get approval
a) approval plan building control department  (JKB)
b) approval plan town planning department (JPRB)
c) approval plan engineering department

hope this answer your question

cheers mate
Izwan
www.archidstudio.com

Subject to DBKL personnel. No, if they think too risky. Maybe yes, if submitted design/document satisfies them.
Without original foundation drawings, nobody knows what is below. Houses are not all built the same.
If you have intermediate ground beam (at middle of living room), then can you demolish that also?
Will the soil collapse during digging, rainy days or due to presence of running water etc.
Can the contractor's worker take care enough not to damage existing foundation while hacking.
Can you dig below existing structure, without destabilising.
Your adjoining neighbour worry also about your works.
All these are only something to think about.
You need to consult experienced engineer and/or contractor.

Unless someone can share precedent case, nobody can advise definite yes or no.
My opinion is, for your case to rebuilt living room with higher headroom is possible to get approval. Lowering existing ground slab to make same level throughout is also doable but need professional input due to complexity. Just highlighting the risks so you are prepared, not saying not doable.
If want to try, you can make the enquiry at DBKL or pay someone to submit application to know outcome.

Legal aside, do it for your safety and if it does not affect others plus no encroachment onto public land.

Small problem. If me, I will go ahead. But do it nicely.

For pavement, try to use pavers instead of just cement for long term. Cement will crack and edges will chipped off.

Tiles will be too obvious on 'encroachment' 😄