Velux window - how wide can I go?

[reubin78]

Looking to cover an existing passageway which runs between ours and the neighbouring property. The passageway consists of brickwork along both sides and one end.

Our intention is to create a pitch roof with velux (or similar) roof windows. The roof will be finished with flat tiles.

The passageway measures approx 1.3 metres in width. The pitch will run with the length of the passageway (I
i.e. higher at one end)

QUESTION: To maximise the light, how wide can I go with a roof window?

 

[Makie]

Are you able to upload some pictures just so we can have a better look at what we are dealing with

 

[catlad]

Two windows side by side is going to be better for structural
reasons.
Velux FK size might work.

 

[reubin78]

Hi,

Not really got any photos to hand (as currently working away from home until Thursday).

You'll have to excuse my lack of info/clarity. A new roof and roof windows is a new area for me. I'm just a DIYer looking to do a bit of research/planning ahead of talking to my usual builder.

The passageway measures approx 4 metres in length and approx 1.3 metres wide. The roof will be higher at one end.

My question relates to how much of the width (the 1.3m) can be utilised by a roof window. I'm guessing around 200-300mm(?) per side is required for the window's flashing kit and the flashing off the brickwork and at least one roof tile width. Is this about right?

 

[Mr Chibs]

I fitted a 550 x 980 velux to a passage way around 1m wide. I have lead flashing on the pitched roof where is joins the house and this took around 300-400mm, so the window is offset, which is OK on the inside due to layout etc.
You need to double up the rafters/trimmers, so possible two narrow ones may help, post a picture, I'm sure you'll get more replies.

 

[datarebal]

you could quite easily get away with 100 mm a side. Tiles above and below none each side. Their interconnecting flashing could be used or a simple lead gutter formed.

 

[DirectRooflightsUK]

It would be best to get in touch with a rooflight manufacturer, that way you can get one custom made so that you can get the best size for natural light.

 

[reubin78]

My assumption is/was that:
custom=expensive (although better end result) while off the peg = less expensive (although you have to base work on standard size units).

Also, off the peg offers a broader level of support/spares.

Is this not the case?