Re: in sims freeplay i can't demolish a house

If there is any item on the lot, you cannot demolish it

Is there a dirty plate left, a small flower?

Do you have a sim living there? Not present on the lot but living there? If yes, relocate him/her/them, same with pets (it was not clear whether you've relocated pets/sims or simply have them hang out outside the plot, like the pet park or wherever)