How big of a hassle and financial burden it would be to transfer the house papers from your Thai partner to your child?

Thai Partner would sign no issues as it is not her I am worried about I am more worried if anything happens to here and her kids from before our time (we are 16 years together)

our son is now 14 years old and official my son according to Thai law.

I think she can make some document stating her other kids have no rights to the house of anything would happen (although how legaly binded is that as I know certain European countries have serious issues with dis willing your kids) and I think she would have certain issues with signing such a paper as now its black on white she is doing what she is doing more of a loose face thing more I guess?

so how easy or difficult would it be to transfer our house to my sons name?

It is up to her and the land office. The cost will not be an issue.

Get some legal advice! The main problem is that you would not be able to sell the house until your son is aged 20, without getting approval from the Family Court in Chonburi, such approval not easily granted.

OP, if I understand you correctly, what you are trying to achieve is that in the event of your partner's death your son (and not her children by previous relationships) own the house.

There is a simply document which will achieve this. It's known as a "will". No need to transfer the house before your partner dies. And, provided the will is properly made, it will be respected. Best to consult a lawyer. Shouldn't cost more than a few thousand baht.

The will should also cover her other assets and who she wants to receive them.

Do you need any provision to ensure that you can continue to live in the house should your partner predecease you? If so, look into taking out an usufruct on the property. (This, however, wouldn't be legally binding should you and your partner [assuming you're legally married] divorce.)

The thing is, whether you write a will or not, the land will be transferred on your wife's death.

The taxes and fees can either be paid now, or they will be paid later. If you pay them now it might be cheaper than paying them in the future.

The fees for transferring to an immediate family member are not especially high. Go talk to the land office. They will tell you what the exact fees will be.

If you have the cash spare, my advice would be to get it sorted now. It's worth it for the continuing peace of mind.

Transfer from parent to child is half the price of a normal transfer at the land office.

In the region of 1.5-2.5% of the land office valuation.

Age of child not relevant to transaction.

Last transfer of gifting to a child was 0.5% transfer duty. Check your local land office. Keep in mind it will be your sons property, no loans can be taken and cant be sold. On his 20th birthday it is HIS to do what he wants with.

OP, if I understand you correctly, what you are trying to achieve is that in the event of your partner's death your son (and not her children by previous relationships) own the house.

There is a simply document which will achieve this. It's known as a "will". No need to transfer the house before your partner dies. And, provided the will is properly made, it will be respected. Best to consult a lawyer. Shouldn't cost more than a few thousand baht.

The will should also cover her other assets and who she wants to receive them.

Do you need any provision to ensure that you can continue to live in the house should your partner predecease you? If so, look into taking out an usufruct on the property. (This, however, wouldn't be legally binding should you and your partner [assuming you're legally married] divorce.)