oil based gloss on top of eco paint

[bsffamily]

Hi folks

just wondering if any one can advice as to whether there are any issues I need to be aware of in putting oil based gloss on top of an existing eco paint on exterior window frames.
If In prep I dont sand through the top coat is it ok to simply put oil based gloss on top or is it neccessary to put undercoat on first.
cheers
simon

 

[Bigshaggy]

should be fine but always undercoat.it gives you a better grip as well as smoothing out the surface