Window boards

[jimbo5050]

What is the best way to install window boards? ie how to fasten them in place.
I am completing an extension consisting of concrete block outer wall with a timber constucted inner leaf wall. The windows are uPVC and so do not come with a rebate to accept the 'tongue' of the window board.
Obviously with the outer surface of the window boards being visible I wasn't sure what method to use to secure (eg countersunk screws, lost head nails etc.)

Many thanks.

 

[masona]

I use gripfill onto the timber area and you could use upvc glue butted against the window cill or sometime I use panel pin in the timber and cut the nail head off and push the board onto it.

 

[nstreet]

I used gripfill for my UPVC winodw boards, just glued then onto the rendered brickwork, after sealing it with pva solution. Scribe the boards to fit the window and a small bead of silicon will hide any minor imperfections in the join.

 

[jimbo5050]

Thanks for the info guys.
Gripfill it is then!!