Flashing below aluclad

[health mechanic]

My rear part of my extension is timber on 2nd floor. My aluclad windows are being fitted in with compriband and then foam inside. Is there a need for flashing at the bottom reveal. Window fitter does not think so...as worried about sandwiching water in. But most videos I have seen seem to have some sort of flashing. Front of house is double cavity without flashing.

[craig]

Depends, need to see what it looks like. Picture or detail would be great but he’s probably right.