In Vastu sastra, a house is called your third skin for a good reason (clothing being considered your second skin, energy-wise). Just like a good clothing increases your positivity, a Vastu-complacent house nurtures your energy and thereby, creates a harmony in home.
For the same reason, it is advisable to adhere to the laws of Vastu while building a house. Constructing a house in the south east direction is a No. If you do it, be warned that you would be buying your keys to a life of fear! If the building is in the south west direction, you would always be in the midst of petty quarrels at home. If it is in the northwest direction, uncertain times are sure to set in. And if you decide on building your home in the north east direction, you would be spurring chances of a total mess in the family.
Vastu is important when you construct your house. However small the house could be, it is imperative that you abide by the measurements as prescribed in Vastu. During the full course of construction, it is a must that the dimensions are strictly adhered to as per the Vastu norms.
While relocating your building
In case you would want to dismantle the house you live in and reconstruct it in another place, make sure the new building is in the south west or north east part of the old location. It is also okay if both the plots face the east. But if you decide to retain the existing building and go for an adjacent new construction, make sure the building would not break the middle line of the plot. It would be best to have one building face north east, and the other one look towards the south west direction.