Private 1st And 2nd Charges On Land And Property

I think we all know about mortgages as 1st charges so you cannot just sell the property and not repay the mortgage ! but what about 2nd charges on a mortgaged property and 1st charges on a mortgage free property ?

Specifically, my wife will at some future time get a mortgage where she (read I) pay the deposit and she (read I) pay the monthly mortgage. The lender will of course have a 1st charge over the property. Can I or anyone else, including a company, take out a 2nd charge and what is the accepted format ?

Secondly, if the property is unencumbered, is there an easy procedure to register a 1st charge on the property, the amount of which either exceeds the value of the asset or which can be varied such as increasing by 10% per annum etc. ?

The end result I am hoping to achieve is that should I pre-decease my wife, I want any assets I effectively pay for to be safeguarded for the benefit of our daughter. Trust law would be the easiest but that does not exist in Thailand.

What I don't want to happen is something like this: buy a property for Bt1m and 15 years later, I die. The property is worth 10m and it is either free of mortgage or there is perhaps a mortgage of Bt0.5m, leaving substancial capital. Whether grieving or otherwise, it would be possible for my widow to raise capital by remortgage, privately or through a bank or sell the property and pocket the cash, potentially putting her at risk of the hoards of non grieving family and hangers on looking for a handout. The net result would be to disadvantage our daughter.

A blunt instrument would be no good as it is black or white; she can sell or she cannot and she may need to.

An ideal scenario would be to protect the interests of our daughter whilst at the same time allowing my widow some flexibility but not sufficient to become the local lender of last resort !