Inheritance of a home can be exempt from inheritance tax if:
a) you have lived in it for at least 3years before death of your parents/property owner
b) you cant own or have an interest in any other home
c) If you are under 55 you must continue to own and occupy the home as your family home for 6 years
So if you can meet and continue to meet all 3 conditions, your parents should they wish to, would be able to build and gift you a house of any value without you incurring inheritance tax
not an answer to your specific question but I hope this helps.