Building a duplex house plan is a good way to start small in multifamily housing. The blog Guide to Finding Your Duplex House Plans is helpful in selecting your construction plans. http://www.houseplans.pro/blog/post/finding-right-duplex-house-plan

Tsilanko, I would always recommend professional installation where needed. But what I am doing here is suggesting that WHEN you are planning to build or renovate, to consider how your plans will affect you in 20 or 30 years time. Split levels are very hep when you are young. A kitchen 3 steps down at 30 is rarely a problem, but might be a hazard at 60, or, as Marjie1059 suggested, if you break a leg. ... All my parents' homes were terrible for old people. They were forced to move to a bungalow in extreme old sge because the location and design of their home was more suitable for an active young couple with a large family than for an elderly couple with stroke disabilities. I would not want to move again, so my present home has features built in that make ageing in place simpler. Mostly small changes, like grab rails, and lever handles on doors and faucets. A major disability suddenly suffered requires major changes if permanent. I did look at this because it came up in the discussion, but if you look at the heading, Planning for Disability, it means just that. Plan ahead so you don't have to make expensive changes later on. But thank you for your advice, yes, major changes are not in the DIY domain.

Hello Abinash, The size and measurements of sofa depends on the piece being selected or made, the seat is usually 16-19 inches high. Note that the seats facing the TV are not having a back support as per the plan or 3 d render. You may want to reconsider this as it is not very comfortable to watch the TV without a back support. For the other end of the sofa hope the TV clamp is movable. You may try the home trial of sofa from Urban ladder and Pepper fry and see how different sofa will look in your house. They serve in metros as of now. They do charge a nominal fee for this service. Guess some 400 for upto 4 sofas. Thanks, Nitin CORNERSTONE DESIGNS Bangalore.

Referring to the sketch above as option 1 you can have two option, option 1, as obvious cutout at the middle of the u shape staircase, in addition to this you can also have a double height entrance foyer with a chandelier in between hanging from the top. on first floor you can shift the balcony door side ways as mentioned with a circle. referring to the image above option 2 option 2 would be a complete change of staircase orientation , bringing the staircase in front foyer, extending the upper cutout as marked in dotted line, the new found area can help you extend your both bathrooms areas or can help you put some ground floor furniture or a informal study area.(see if your FSI permits to all these changes). and on the top your new area can accommodate your big gym equipment's like treadmill , and some additional gym storage. here you can also get to know from top who has arrived to your front door peeking downwards. further the walls of this area can be decorated while doing interiors and make the foyer look grand & luxurious. option three, If you are thinking of giving a cutout in center of the hall, please avoid, your areas above wont be usable in an appropriate way. cheers