Velux installation in new roof

[Mikejf]

I'm about to set out the rafters on a new extension. The roof will have a Velux M06 window so I want to set out the rafters to suit.

I have the insructions for the Velux GGL but they show 4 different opening at section 4. Sections 4a, 4b, 4c and 4d. I can see 4c and 4d are for different tiles but not quite sure what a and b represent. Any one have any ideas as there is no text descriptions.

When I space the rafters around the window I'm unsure if I leave a space of the window plus 40-60mm or 10-60mm as per 4a or 4b. The vertical is the same so I assume this is the window plus 45mm between the noggins/support.

Many Thanks

Mike

 

[badgeraudio]

We have recently put one in our new extension and had to do the same as you.
We followed 4a.
Remember to think about tiles sizes and layout, so you can try to place the window in a position where you will have to cut the least amount of tiles.
I did not think about this till a bit too late. But I moved the window forward 100mm or so to make it sit better with a row of tiles.

 

[hammerswinger]

I have 3 velux's in my lean to extension and I set the rafters out for the velux holes as I went....I ended up having to cut the tiles either side of every window

I posted on here about it and the more experienced guys told me that they lay out the 1st course of tiles at the bottom of the roof to get the best side to side position for the Velux!

This is the thread:
//www.diynot.com/forums/viewtopic.php?p=2037004#2037004


If the Velux has to be in a certain position for some reason, like keeping it central in a room or something, well there's nothing you can do about that, but if the side to side position isn't that crucial you can maybe move it a bit to save cutting the tiles.
One of mine had to be in a given position so that would have had cut tiles regardless, but I could have moved the other two a little to save me some cutting.

If you're only fitting one Velux I think I would just lay out the rafters as normal and tile the roof, then fit the Velux afterwards....might sound a bit daft but that way you're certain of getting it in the best place.

Hope this helps a bit.


Cheers.

 

[Mikejf]

Thanks for the replies. Great advice. The window will have to be central on the roof or it will look odd in the room but I will look to position it to suit tile height to save cuts. I may even splay the reveals.

I was just going to buy the window and the flashing kit but notice in the instructions it asks for BFX, BDX and BBX kits. I've read these are not required and are just an optional extra. Can anyone confirm? The BFX kit looks like it has a rain channel or something that is installed at an angle above the window to route water away and to the side of the window. Is this required? My roof is just rafter, membrane, batons and concrete profile tiles.

Many Thanks

Mike

 

[badgeraudio]

Rightly or wrongly I did not go for any of the extras.
I think the rain gutter is only used on roofs where you have the laths running up the rafters as well as 90 deg accross them.

I just made my own coller and insulation ring using membrane and spare kingspan from site.

Mike

 

[hammerswinger]

As badgeraudio did I also just used the membrane I used under the tiles to form the collars etc.

Cheers.