Velux on kitchen roof

[jackg]

The exsting windows are small and on one side only so the room is dark.
Trusses are 400mm. I have seen pictures with Velux spanning 2-3 trusses but with no noggins.
So do Velux make bespoke windows such as 400 wide, as the std ones are 550 minimum, or is it best to span more than one truss?

 

[Bonni]

If on a new roof I'm building, I double up the rafters on either side of the rafter that's cut and trimmed because of the velux.

With existing plasterboard and roof tiles in place, doubling rafters would be nigh on impossible without removing plasterboard or roofing material. Would not doubling up be an issue? Doubt it but not 100% sure. So a velux spanning across a rafter, the rafter just needs cut and trimmed. Trimmed means a horizontal noggin between the two rafters to attach the cut rafter to (a trimmer at the top and a trimmer at the bottom).

The reveal at the top of the velux should be as horizontal as possible, and the bottom reveal as vertical as possible to allow maximum light in.

And an external trim kit that's suitable for the size of velux, the tiles, and pitch.

 

[catlad]

Depending what size you already have you could increase it to the largest size in that range 55 x 120
Velux also so do combi flashing kits so you could have two side by side.