Stamp Duty

Ruggers13

Apologies if this is in the wrong section.

Basically my partner and I both own a property with mortgage. The plan is for her to move in with me and rent out her property. We then want to get her onto my mortgage and then will have a share in my property.

Say we complete a declaration of trust to say her share is for example 10% then would the additional stamp duty tax apply to the 10% or the full value of the property? 

Mark_d

So you own a property on mortgage and your partner owns a separate property on mortgage.  Your partner wants to live in your property and take a 10% share ownership in this?
The stamp duty calculation would need to account for the equity in the property, the type of mortgage arrangement etc.  It's not straightforward.