Swapping Velux for a smaller one...

[MattChan]

I have a GGU M04 Velux with EDW flashing fitted to a 15 degree pitch roof tiled with Marley Wessex tiles.

A new wall is going to overlap this window so it needs swapping to a GGU FK04 which is 120mm narrower.

Do I need to add a single or double new timber between the top and bottom trimmers on the side where I am filling the 120mm?

 

[tel765]

You've nothing to lose by fixing double "new timber".

 

[^woody^]

Any new timbers should be suitably bolted, and maybe use spur washers, to the rafter and properly fixed to the trimmers, so that the window load gets transferred to the rafter. Not just a few nails.

 

[MattChan]

Interesting given the existing trimmers just seem to be screwed to the rafters, no hangers used etc!

I take it i should fix that up whilst im in there?

 

[^woody^]

trimmers just seem to be screwed to the rafters, no hangers used etc!

Which is correct, although nails would have been OK.

 

[MattChan]

Phew. I get what you meant in your first message now. Thanks!

In terms of the breather membrane, I think at the moment I just have a rectangular hole and I understand I just tuck the new piece under the top of the hole and overlap the bottom. I cant figure out what I would do at the side of the hole? Tuck under?

 

[catlad]

Yes cut a piece so it goes up the side of the frame 2or3 inches and extends to the next rafter.