what size aperture for a 550 x 980 Velux ?

[Post and beam]

Our build has an opening for what we have always expected will be a 550 wide by 980 tall Velux. The TF frame has been constructed with an aperture that is 1470 tall. I pointed out that this is a mistake and have been told that it is not. The Velux should be placed centrally into the opening and then boarded internally at 45 degrees to maximise light.

This does not address the 'too big' opening on the external side. I will be contacting Velux on monday but does anyone have experience on how these are fitted into the build and the gaps around. Becuase i think i am being fed a crock from my TF suppler.

 

Thanks as always

[nod]

Fit the Velux window to the opening 

Then simply fit double nogs to the bottom and top afterwards I personally hate splayed reveals I normally line with ply to square them up slipping  the ply to the back of the frame Which allows the PB to slip into the groove on the frame 

[Russell griffiths]

Better to be too big than too small, just adjust it when the velux gets fitted. 

[Rishard]

We often over size the ‘height’ which allows for some adjustment up the roof to work with your roof tiling/flashing kit. Once the window is fitted the opening should have a plumb piece of plasterboard running into the low side of the velux and a horizontal plasterboard to the head. This allows air to flow in and then out of the velux reveal. All standard practice and outlined in the fitting instructions. 
 

The rough framing is always better left taller on height to allow for this. Hope this helps. Width is usually 40mm oversized for perimeter insulation depending on supplier.  

[joe90]

I always fitted the velux to suit the tile/slates, much easier to input timbers where required .

[Post and beam]

Thanks guys