velux framing

[iep]

I'm installing a velux window into a loft space and want to sort out the framing before cutting through the sarking boards. The rafter spacing in our house is approx 400mm so I need to build a frame that allows me to safely cut a section out of one of the rafters (as per the image below)

Untitled

• iep
• 7 May 2012
• 1

The velus installation guide gives some detailed info about sizing of the framing but I can't find details about how best to construct the framing (timber sizing etc).

My guess is that using the same sized timbers as the existing rafters (6x2) and nailing/screwing these togther to create the framing will be fine. However, perhaps I'd be better using joist hangers or something similar?

Cheers,

iep

 

[denso13]

Yes, use the same size timbers. Joist hangers might be overkill in some situations but they are not expensive, I usually fit them.

 

[iep]

Ta denso, useful advice. Any other pitfalls you can think of?

My plan is to build the frames ahead of time and then get the roofer in to cut the holes and fit the windows themselves. Any downside to this approach (for example, does the roofer usually cut the hole 'sympathetically' to position of the rows of slates?

Cheers,

iep

 

[denso13]

Can save a lot of trouble if it is fitted to suit the tile courses. Helpful roofer might give you the position in the inside for you to fit the trimmers as it would make it easier for them. Then again......

 

[iep]

Good point. Strikes me I should be able to work that out from the row of nails poking through the inside of the sarking boards?

If I reckon on the cut being one slate's length below the previous row of nails (plus maybe an inch) then that should be about right.

Cheers,

iep

 

[Roofer]

A much nicer finish is possible if instead of the trimmers being installed at right angles to the rafters they are put in horizontally at the top and vertically at the bottom giving a splayed appearance.

It's a bit difficult to explain but if you look carefully at a lot of the pictures in the Velux brochure you will see what I mean.

It looks a load better and is worth the extra effort

 

[iep]

Hi Roofer. Afraid I don't quite follow what you mean but I am keen to understand as I need ot get the finish right on this.

Are there any links or images that you could use to illustrate the approach you are referring to?

Cheers,

iep

 

[Roofer]

Look here at the images next to the headings 'centre pivot', 'smoke vent' and 'accessories'

http://www.velux.co.uk/private/products/velux_roof_windows

See how the opening is formed

 

[iep]

Got you! Yes, looks much better.

Thanks,

iep