Just do it. Get a contractor, contractor can advise if there are pillar cable or pipe and reroute the cabling and pipe. Beam, no problem. Demolising can be done in a day and the contractor can clear it in a day. repatching can take time to do it. If so unfortunate the authority come, no harm, it is not a major reno need no permit. If you submit plan it takes 6 mths!!! By then you have already change your mind or original plan!

A malaysian story.

my immediate neighbor doing major reno tong tong ding dong without applying permit. Half way the local authority came issue saman. The house owner paid the fine and some other expenses totaling rm1,500 and submit plan. The contractor continued tong tong ding dong till finished without waiting for the approval.

Another neighbor already completed major reno. Submit plan pay fine. Everything was fine.

My tenant moved out and I stop renting the house I used to collect rm750 a month. Submit plan, the officer warn me not to start reno as they were already been alerted by my submission. so no choice have to wait for the approval. waited for 6 months after going there few trips to ask for status, got the approval start reno. Stupid isn't it? If i did like my neighbor I wold have saved more money. Rental 6 month x 750 = rm4,500 - fine and some expenses rm1500, I still save rm3000!