i'm thinking to extend my kitchen out. initial planning is to extend around 11ft (long) x 10ft (wide).

However, the initial planning will cover up one of the septic tank manhole. Contractor advise not to do so just in case there's a blockage in the future.

Due to this, the extension of my kitchen become 11ft x 8ft only which is kinda small.

My question, is it ok to cover up one of the septic tank manhole for a bigger kitchen?

Any suggestion on the living room TV placement? Red wall in attachment is new extension wall. Suppose TV location is on the left side wall going in from main door. but due to feng shui issue, sofas not able to put in the middle of the living room cos sofas backside facing main door.