On a side note: If these suggestions are what you would consider lackluster, you should look to professional custom home builders for better ideas. They have dealt with these kinds of sibling room dilemmas before, and would have the best professional advice.
Bunkbeds are Godsends
For multiple kiddos in the same bedroom, bunkbeds are an absolute must-have. These go-to furnishings ensure that youngsters can sleep in the same room at once, without sacrificing space for ginormous beds. Back in the 80s, bunkbeds weren’t very comfortable. The mattresses were thin and lumpy, much like an old-fashioned futon. And you never knew when your top bunkmate would shift and come crashing down. However, revamped and modern bunkbeds offer better support in plush mattresses, and a steadier, steadfast system that holds the top bunk in stable place. Plus, bunkbeds can inspire imaginations, since a sheet can be tucked into the top bunk to flow down and create a canopy/fort for the bottom bunk.
Draw a Line Down the Middle/Halve the Room
As kids get older, they want their own space to be creative and expressive. When your children reach those preteen years, perhaps split their bedroom down the middle. Use a piece of painter’s tape, or make an agreed invisible line, to halve the room—one side per kid. Children can decorate their side however they please, from punk rock in hot pink and solid black, to band geek with music posters and instruments galore. They can also decide on neutral territory, where both kids can gather for lounging conversation and leisure time.
Decide on a Central Theme Together
If your kiddos get along and share some of the same interests, they could decide to keep their bedroom as-is, resulting in a central theme that they can design together. For example, some teenage boys go with music and video game themes. The color of the walls doesn’t matter so much, but you will need hardwood floors [because teenagers are messy], a couple of gaming chairs, and an entertainment stand for their consoles. You should also make sure there is plenty of wall space for their music posters.
The aforementioned interior design ideas are great for siblings that room together. Sure, your kids might still have a tiff or two over their bedroom space, but these ideas can cut down on arguments and encourage collaboration.