Vastu says that if a house is commenced on the first tithi, there is poverty, if on the fourth lunar day, loss of wealth, if on the eighth day eviction, and if on the ninth day, danger from weapons. It has also been said that the Lagna at the commencement of the building should not be flanked on either side by malefics and Upagrahas. The bad days caused by tithis and weekdays and Naksatras, and those prohibited for marriage- muhurtas are prohibited for Grharambha also.
The Vastu Chakram is as follows:
The stars from that occupied by the Sun indicate the different reckoned parts of the body as follows:
1-3 Stars - Forehead
4-7 Stars - Front toe
8-11 Stars - Heel
12-14 Stars - Back
15-18 Stars - Region under right shoulder
19-22 Stars - Back (tip of the spinal region)
23-25 Stars - Region under left shoulder
26-28 Stars - Face
With regard to the relevance of Muhurta in Vastu Sastra it has been said that if the star falls on the forehead, fire accident takes place; if on the front foot, prosperity of the house; if on the heels, permanency; if on the back, financial benefits; if under the right shoulder, all types of profits; if on the tip of the spinal region, the owner will suffer very badly including destruction; if under the left shoulder, poverty; and if on the face, permanent problems.
Some of the important aspects of Muhurta and Vastu are: It is said that:
Construction of the entrance of Labour Room should never be undertaken during Chara Lagna and Cam Navamamsa.
The Upasraya house (third, sixth, tenth or eleventh) from Janma Rasi, as well as the eight sign from it should not be the rising sign for starting construction.
Vastu says that if Jupiter is in Lagna, the Sun in the sixth, Mercury in the seventh, Venus in the fourth, and Saturn in the third, the house constructed will last for hundred years.
Similarly if Jupiter is in the fourth from the Ascendant and Moon in the tenth, Mars and Sun in the eleventh, the house constructed in such a Lagna will last for eighty years. If Venus is in the Ascendant, Jupiter in the fifth, Mars in the sixth, Sun in the third, the house constructed will last for two hundred years.If Jupiter and Venus are in Lagna and Mars in the sixth and Sun in the eleventh, the house constructed in such a Lagna will last for two hundred years.
Vastu Shastra has also talked about various other positions of the planets and similarly has also explained various Muhurtas. For instance it has been said that if Venus is in exaltation in the Lagna or Jupiter is exalted in the fourth and exalted Saturn is in the eleventh, the house will last for many thousand years.
If the Moon is placed in Karka, i.e. Cancer Lagna, Jupiter in a Kendra and benefics in friendly or exalted houses, the house commenced during such a Lagna will last long and will be a wealthy house.
The house commenced in the star Pusya, Uttard Phalguni Uttarasadha, Uttarabhadrapada Aslesa, Mrgasirsa, Sravana, Rohini or Purvabhadrapada will be a house of wealth. Vastu Sashtra states that the house commenced in Visakha, Chitra, Satabhlsa, and Punarvasu, when the Venus is in Dhanisthd, that house will always have the granaries full. A house commenced in Hasta, Uttard-phalguni, Chitra, with Mercury in Asvini and Anuradha, will bestow financial happiness to children.