I assume that you will be treated as disposing of half of your house and she will be treated as receiving a gift of half the house?
As it is your principal private residence, then there will be no CGT as nige has pointed out.
If she buys her half at market value, there will be no gift and so no CAT.
Even if you give her a gift of it, if she has been living in it for 6 years, there will be no CAT.
Why are you putting her name on the deeds? If at some later stage, she wants to buy her own house, she will lose all the valuable benefits of being a first time buyer.
Why not leave the house to her in your will which will give her some protection and it will have no negative tax consequences?
Brendan