Vastu Shastra is of paramount significance in Indian culture and it has a rich heritage. Land is the most important criterion in Vastu. Vastu is also classified into different categories on the basis of Jati and Varna. In Jati there are the Devata, Manava and Raksasa. In Varna we have Brahmin, Kshatriya, Vaisya and Sudra. A careful study of Vastu reveals that the whole movement of Vastu was genuinely and positively scientific, the ultimate goal being spiritual. Vastu, though mainly akin to the earth, is also concerned with other Mahabhutas. Hence, based on the pronounced effect of different Bhutas, lands can also be classified.
The classification of Vastu according to the parameter Jati principally has to do with structural elegance and material management. The classification of Vastu in accordance with Varna mainly has a professional view and cultural needs.
Vastu has remained so important right from ancient India that it finds mention in Agamas, such as the Karnikagama, Suprabhedagama, Vaikhanasagama, etc., and works on Tantra, such as the Hayasirsa Tantra, Kiranas-tantra, and Puranas such as the Agni Purana, Matsya Purana and Vishnu Purana and a lot more.
Vastu principles are more or less common all over India, living from times immemorial as a cultural entity. Vastu has retained its traditions for thousands of years and it is as relevant today as it was when first propounded. There are also Vastu texts for Jainism and Buddhism, such as, the Gautamiyam, Bauddhamatam and Chaitya. The Vastu Silpa traditions are purely Indian in its fundamental concepts and currency.
In Vastu much importance is given to the Sun`s movements in the heavens in placing the construction of a house in such a manner that more open space is left and more windows and doors are provided towards east and north than towards west and south so that a house is exposed to maximum influence of solar energy.
Modern engineers, house builders and architects will be surprised to know how our Vastu experts devised simple methods and most inexpensive contrivances for examining a site, measuring and taking possession of it, orientation, etc. They are advised to study carefully what is called Ayadivarga. This is said to enable one to find out the fitness of the structure and ensure well-being of both the builder and owner. Terms like Dhwajava, Sirhhaya, Vrsahhaya, Gajaya, etc., are said to be auspicious; while those like Dhumdya, Svdndya, Khardya, etc., are inauspicious.
Vastu Shastra is important in the construction of houses because if proper science of Vastu is not followed in the construction of houses. For instance no house of the shape of a triangle should be built as it is said to cause early death to the owner and it should not remain unused for long time.
Other important rules are given for the construction of public buildings. According to the Gupta-Vastu, when constructing schools and other teaching places, walls in the East and North must be constructed first. The Southern and Western walls are to be constructed next. It is also advisable to have a common wall for two buildings. There are other helpful hints. For instance, if an old house is to be reconstructed only new wood should be used. Nor should one use old wood for a new construction. There is no aspect of human habitat - homes, factories, offices, etc., which cannot find a place in the Vastu scheme.
Finally it can be said that Vastu is important in all kinds of construction because it brings about harmony in the building and when there is harmony in the construction itself it is natural that there will be peace in all things that are done in the building and also the people residing in the building will have a sense of fulfilment.