Right now according to how bright the roof is on the right side it gives you the impressions of a really hard light coming from the right. The thing with a hard light source is it casts a hard dark shadow, void of much light and depending on where that light source is it could cast a really long shadow too.
To demonstrate a crude edit, I didn't cast the shadow on the front facing side of the house as well as some other minor parts. But you get the idea. I'd even go further and make the shadows darker.
What I actually think you're going for is a more global light source like that of the sun. Based on the shadows I'd say the "sun" is either rising or setting, which is why its casting as much of a shadow as it currently does. My point here is that a global light source is so large and so high above, that overall the values are higher, shadows are softer all due the light source covering such a large area, as well as light bouncing around. So things like the left side of the roof would probably be getting more light because the light source is above, but not receiving as much as the right side because its not directly facing the light source. The soft shadow is then fine as is and it will just allow the building to pop out correctly.
Its actually something Dpixel did correctly in his edit
Yours vs His.
It's amazing how something so small can make a huge difference.
Lastly, the background is rather dark at the moment. With all that light I think it makes sense to brighten it up.
Sorry about the ramble, hope it helps though.
