thila homam should not be done in houses. along with black ellu paddy should also be mixed for thila homam. Lord rama after killing ravana a brahmin brahmahathi dosham followed him. Lord Rama has done in many places thila homam. But only at Rameswaram after doing thila homam that brahmahathi dosham left him. So Thila homam must be done only in rameswaram.
thila homa mantras are veda mantras which should be done only by learned sastrikals. this is done only a a praayaschiththam for pithru sapam and pithru dosham.
if mandhi is there in your horoscope in any one place from lagna in 2nd, 4th, 7th, 8th, 9th ,12th places denotes pithru dosham. for all unnatural death like, accidents, poison drinking, suicide falling from tree, etc. thila homam should be done. knowingly sraatham has not done. thila homam must be done.According to severity of pithru dhosham you may have to do from 12000 aavarthis to 30,000 avarthis thila homam, which can be find out by prasna aaroodam.