This should work;
1) Click on the house you want to delete
2) If you wan't to keep a certain family in that house then the best thing to do is exict or move them to another house.
3) Once you've done that, click on the play button and go into buildmode
4) There should be a little truck/lorry in the top bar (if not, click on the house with the 'i' on it in which is also in the top bar and the truck should be there on the right-hand side
5) Simply click the truck and it'll come up with a sign asking if you'd like you bulldoze your lot, click yes and the house should be demolised after about 30 seconds on the loading screen x
Hope I helped x
