You say you want to build a house on the vacant plot for your living, and the property should go to your son afterwards. In the circumstances, the best way to do is leave him a Will. You may get it professionally drafted by a competent advocate, execute it in the presence of two competent witlessness and get it registered. Your son's presence is not required in this case.

If you leave a Will, no further action is required by him. He is legally entitled to the property when the eventuality happens. His presence now is not required. There is no stamp duty, and registration charges are reasonable.

You can transfer the vacant site to your son by a registered gift settlement with a condition of life interest in the property retained by you.

For registration he is required to be present before submitting registrar without fail.

You can execute conditional gift deed in favour of your son 

it attracts nominal stamp duty and registration charges 

Yes, the process of enforcing the Will may be cumbersome at a later stage hence it is advisable that you transfer the same by registered settlement deed, however it is mandatory that he has to be present physically before submitting registrar to accept the settlement deed and sign before the sub registrar.

Will takes effect on death of testator 

best option is for conditional gift deed 

gift deed should be accepted by donee 

- If he is not here , then you can write a Will in his name after giving all the details 

- You can even registered the Will in his absence , however registration of a Will is not mandatory. 

- The Gift deed is a better option to transfer the property to your son , however his presence is needed before the Registrar 

- The registration of Gift deed required nominal stamp duty if it is registered in the name of blood related. 

- Further, if he is out of India, then he can give POA to any relative in India for the said work on his behalf. 

He can give POA to any relative and than can execute gift deed. 

Do a gift deed of the vacant plot 

In the deed mention that the donor will be entitled to construct a house on the plot and after him, the donee will be entitled to the house. Also mention that the gift is conditional upon the donee son permitting the donor to make construction on the gifted plot and live in that construction for his lifetime without any obstacles by the donee and also till the donor is alive, the donee son will not be entitled to sell the gifted property 

A conditional gift is legally permissible 

The son will have to sign on the gift deed being the donee 

If he is not available for signing and registration then he can grant a poa to someone who can sign on the gift deed and comply with the registration formalities on behalf of the donee son 

A Will can also be made but the Will would take effect only after your demise 

In the future you can also make another gift deed to transfer the constructed house to your son with a condition added that till the time you are alive he will not be entitled to sell the property and you would be entitled to reside in the constructed house for your lifetime. This will confer a proper legal title on your son for the plot as well as the construction made on it 

Dear Client,

A Gift deed will be the best option because it will enable you to transfer the title of the house to your son instantly, is cheaper as it attract lesser registration fees than a will and does not have some of the drawbacks of a will which transfers the ownership of the property after the death of the owner.
However a Will helps transfer property only after your death and may require probate process which is a little formal and lengthy
And the purpose of the gift deed is good to which your son’s presence is not necessary if he hands over the power of attorney to a third person and identity proof of your son. This ensures that this transfer can be effected without him and without any complications. Therefore, Gift Deed is a better option for the instant transfer with easy registration and free from most of the hassle issues in the future.

Thank you.Hope you find this advice beneficial.