This must be a massive house if the tax ( at 25%) would be €300,000.
If you have proof that you paid for the building costs, this would be "consideration" to be deducted from the value of the property you would be receiving. Also you have a 2010 threshold of €414,799, (unless you have already received gifts in this category i.e from your parents) below which the gift is tax-free. Plus a small €3000 annual gift exemption.
Only the value less exemptions and consideration would be taxable.
If the gift is being given to you and your husband, his benefit may exceed his threshold, as your father is a "stranger".
One would have to look at actual values and previous benefits taken to say what the tax, if any, would be. It may be preferable for only you to be the recipient of the gift; it may be better for you to share it.
However, if your parent is not living in the house, you may even qualify to receive the house plus one acre of land exempt from CAT.
If you have lived in the house for 3 years without your parents present, and own no other residence, Section 86 should apply, and no CAT be payable. However, the house may have to go in your name only, an if so, stay in your ownership for 6 years, or there would be a clawback of relief.