If you dream of entering someone else's house, it signifies your victory over a competitor or adversary. Such a dream indicates that you will establish dominance over them in business or other areas. It symbolizes your confidence and power, which will aid you in achieving your goals.
From Imam Muhammad Ibn Seerin's Dictionary of Dreams According to Islamic Inner Traditions â entry "Entering a house" (page 142).
If one sees himself entering someone else's house in a dream, it means that he will defeat him, gain the upper hand in business over him or control his interests. To enter the house of the governor and to feel comfortable
and at ease therein in a dream means that he is soliciting the governor's assistance in a personal business. The coming of a just person to a house in a dream means blessings. If an unjust person enters a place in a dream, it means that evil and calamities will befall such a house. If it is customary for such a person to enter that place, then no harm will incur from his coming or going. If one sees himself entering a house of unfamiliar substance, ground or structure, and if he meets departed souls whom he recognizes in the dream, it.means that he has entered the realms of the dead. If he sees himself going into that sphere, then coming out of it in the dream, it means that he will near his death, then recover from a serious illness. Entering the Sacred House in Mecca in a dream means entering one's house as a newlywed. (Also see Marketplace)
Note: Islamic dream interpretation depends on the dreamer's circumstances and state. This is a general guide drawn directly from the source book.