House warming ceremony or Gruhapravesham or ‘Palukachu’ in Malayalam, is done after the construction of a house, which is mostly based on a Muhurtha (Auspicious time) for Gruharambham.
At the outset, a Muhurtha is got prescribed by a learned Astrologer for beginning the construction of the house (Gruharambha Muhurtham). Of course, it is nice if you resort to a ‘Daivadheenam’ (God’s blessings), through a Horary (Prasna) by a learned Astrologer, even before purchasing the land for constructing your Home/ Flat. You can verify with the Astrologer whether the land is suitable for making a Home for you and whether you can go ahead with the work of construction without any hindrance or the like things. Usually people will say that you should not begin such things when there is a fully pregnant woman waiting for child birth in your house or a very pretty old one is bed-ridden at that time.
The following 18 Nakshathras – Moolam, Makam, Rohini, Makayiram, Chathayam, Punartham, Pooyam, Uthram, Atham, Chithira, Uthradam, Thiruvonam, Avittam, Uthrittathy, Revathy, Ashwathy, Chothy, Anizham – are supposeed to be good for Gruharambham. Usually we do not take the 3rd, 5th and 7th Nakshathras from ours for all auspicious things. Of course, there are some exceptions for certain particular Nakshathras, which the Astrologer will tell you at that time. The Malayalam months like Mithunam, Karkkadakam, Kanni, Dhanu and Meenam are avoided for Gruharambham. You should never go for it, when the Sun is transiting through Karthika Nakshathram. There should not be Mars in the 8th house from the Muhurtha Lagna. The 4th house should be clean; no malefic is allowed there. Also avoid Sun in the Muhurtha Rasi.
The most important item in Gruharambham is laying the foundation stone or ‘Adisthanashila’. It is called the ‘Shilasthapanam’. So, it should be done exactly at the prescribed time for Gruharambham. Many people do a ‘Bhoomipooja’, before laying the foundation stone. Some are seen getting that stone blessed from their ‘Ishta Devatha’ Temple. Arranging a small pooja on the spot is very welcome, seeking the blessings of Lord Ganapathy and other Devathas, including Vastu. The excavation for foundation can be done little earlier to laying the first stone. But, it is a custom and almost a belief that at the time of the excavation for foundation, Bhoomi pooja can be done. The excavation should be started from the North-East corner (Eshana cone) of the plot and the Bhoomi pooja also should be arranged to be done at that part. Before starting excavation, usually a fresh stump from a jackfruit tree or from a tree having sap, is fixed first exactly at the NE corner. It is from that stump, string is connected to those at the other corners, to ear mark the area for excavation for the proposed house. Some people use the Muhurtha for Gruharambham for fixing this stump. It is not correct. The Muhurtha should be used for laying the foundation stone. Of course you can use a good time for fixing the stump also, just before laying the stone. You need avoid Rahukalam, Gulikakalam and Yamakandakalam, which are readily available in every Calendar.