Floating or bonded

I’m buying a herringbone engineered wooden floor. V4 are telling me it’s need to be bonded. Other company’s say it can be floated or bonded. In my head floating using underlay provides extra protection due to the damp proof membrane. Can I do either? Lots of conflicting opinions

 

I always advise bonded

 

You have to fully bond v4 herringbone. Its only t and g on one side that’s why they advise you to stick it. Youll need to apply a surface dpm if you dont have one

 

What company’s say it can be floated ?

 

Always fully bond