How to build a dormer window?

[Lobster]

Further to my earlier post about venting my rafters (thanks for the reassurance, John!) I have another query...

SWMBO's just come downstairs again after having apraised the day's efforts on her way to bed. "You know, wouldn't it be nice to have a dormer window in the other side of the roof... think of the extra light... would transform the room.... enhance the house value... etc etc".

Jesus H Christ on a broomstick! "Noooooo!"

So she's gone off to bed in a bit of a huff, but notwithstanding my protestations I just thought I'd have a look round to see what I can find about How To Do It - which is not a lot so far. I wouldn't have a clue where to start TBH - my only clue will be from exposing the workings of the existing dormer on the opposing side, when I have finished ripping off the old lath and plaster for the purposes of insulating it all properly.

Can anyone point me at some Useful Resources? (and don't let on to SWMBO that I'm even considering this. But she's right of course - as usual).

Thanks David

[John Rumm]

Some photos/drawings would help.

Depends a bit on the scale of the dormer required! At one extream you can go for the "F*Off big as you can physically make it dormer" (for my attempt at this see here:

or you may be talking about a bejou little bump on the side of the roof a couple of rafters wide.

The massive dormer in effect means you are removing the balancing half of the roof that stops the other side falling over - hence you get into complications of how to now support the bit you left. The smaller dormer can probably go in without any such consideration. Especially if you already have one and wish to balance it with a matching one on the other slope of the roof.

They are not complicated things to build generally - some studwork and a bit of ply, insulate, and render or tile hang the outside, stick a roof on. If you need aesthetically pleasing little bonnet roofs on them then they take a bit more work than a basic flat roof jobbie.

The work will almost certainly need to be done under the supervision of building control, and may require planning permission if you are affecting the elevation of the roof facing the road (or in a conservation area etc).

[Phil Anthropist]

No actual plans as these depend on the existing roof structure, but plenty of guidance:

Either you or an architect would need to draw up plans for planning permission and building regulations. Based on the plans, only you will know if self-build is within your DIY capabilities. A well-designed and well-built dormer is likely to enhance the house value.

[Dave Plowman (News)]

Is this to the front of the house? Do others in the street have one? In certain areas it might be difficult to get permission to do this.