Looks very good, but it's all a bit too bright and shiny. The bricks are too red, the white is (way!) too white....
This will make you an e x c e l l e n t diorama if you weather it with black/grey/brown shades.
If you want to give this a whirl, try the following :
1) ffill a bottle cap with white spirit and add the tiniest bit of black to that. Mix into a very clear grey liquid, and liberally paint the whole building. When dry, do that again. Let dry. Paint again. Till it looks like you want it too. One warning : don't put too much black into the mixture. You may want to do that to "get there more quickly. Don't.
When drops run down making vertical stripes : let them. That's what rain does to a charred building. Black particles will creep into the crevices and cracks, giing it more depth.
2) try to figure out how much brickwork, rooftiles, wood are missing to complete the house. That's the amount you want to see laying around this house. Make small bricks, pieces of plumbing, boarding, electric wires, furniture, heating, broken windows, rooftiles... Paint them in the desired colours and sprinkle them around. This should be a huge pile of rubble !
3) Next, you need dust. Dust is the colour of cement. Why not try real cement ?

Make sure the diorama is dry, then thinly sprinkle DRY cement over it all. Tap the diorama base slightly a few times, so the cement falls off the large surfaces and piles up a bit in the corners. Then spray water thinly with a plant sprayer. Let dry. You can repeat this if you think it deserves more, or put some cement into specific areas. Note : rooftiles are not cemented. You can use a bit of shaved brick or shavings of a terracotta flower pot over your rooftiles.
4) Did the place burn down ? So where's the ashes ? Again, you want to use the real stuff. Fine gray ashes like you find in the bottom of your fireplace.
The house you built is an excellent starting point. This will be a GREAT lillte dio !