this is not a modern house, its a 70's house.

also not sure why there is an inaccessible flower garden taking up half of your roof.
the front peak is filled in with a brown 5x high brick, the slanted bricks should actually continue up instead of what you've done.
also the two floors are clearly divided by large plates that protrude into your exterior walls. This should not be happening as houses generally don't have interior floor poking out the sides.
as oasis said, the ceiling should be higher and they should also be plated so you don't have that ugly bottom stud texture.
There should be interior walls instead of just the back of the slanted bricks. This way you can individualize your rooms better.
There is an absurd amount of brown being used, don't be afraid to use vibrant colors.
Here's an example of the plated ceiling with good ceiling height and color choice. It uses interior walls and does not over use brown. This was made by Blur.

also here is an exterior of a modern house. Try to follow the principles of this as it pertains more to an actual modern style. It uses dark brown accent to stand out against the white, don't be afraid to get past the monotone browns. It does not divide floors with plates, and has peaks filled in correctly. This was made by me.

Overall i feel this build needs a lot of work but as a structure it has a solid design.
4/10