I've been doing some work on this today and as its a subject that has arisen a number of times in other threads so thought is was worth further discussion and input.
As a background: Velfac are very adamant that their windows should not be installed before the render as they cannot guarantee a weather tight seal.
Having spent some time today looking at their standard interface details I can only conclude that it is simply that they don't understand the concept of placing the windows within the timber frame (preventing cold bridging).
You can see their various interfaces drawings here: http://velfac.co.uk/...erface-Details/
Now if you focus on the one for installation into a timber opening. It is quite clear that a weather tight seal can be achieved
2016-04-28_15-41-31.jpg 35.73K 20 downloads.
It would then be a simple case of rendering to a stop bead?
So why all the fuss?
Edited by Barney12, 28 April 2016 - 05:18 PM.