Skylight on a flat roof?

mchardo · 02-17-2009, 05:52 PM

Hello,
I'm looking for any advice or previous experience on installing a skylight onto a flat roof. I have a 2-story home in Minnesota with a full walk-up attic. I am in the process of finishing off the attic to create a "hobby room" for the wife. My house is a 4 sided hip roof with a 12'x12' flat roof at the top of the house. Very common in the early 1900's.

I would like to install a skylight in the flat part of this roof to allow some natural sunlight to enter the attic. According the all the literature on skylights, they all say to install at least a 15 degree mounting frame on which to install the window so that the window is at least at some angle.

Questions: Are these 15 degrees enough to prevent damage from a storm? Are these mounting frames known to leak? or is it better to frame up my own angled window support? Heck, is this a good idea at all to install the skylight?

Thanks for any help

rustyjames · 02-17-2009, 06:08 PM

Questions: Are these 15 degrees enough to prevent damage from a storm?

Yes

Are these mounting frames known to leak?

Not if properly detailed

is it better to frame up my own angled window support?

If you know what you're doing it's fine

Scuba_Dave · 02-17-2009, 06:13 PM

I installed a 606 Velux at my last house on a flat roof
I cut 2x12 to form an angle to slope the skylight
I used flashing & tar to seal the skylight to the roof
Never leaked in over 7 years
Ice & water shield is a good idea to use also

Current house I have 6 skylights installed on roofs under 15 degree pitch. Ice & water shield on roof, flashing - no leaks

AaronB · 02-17-2009, 10:27 PM

If you know how..........

you could frame a 2x12 curb and have a double paned insulated poly skylight bubble made and shipped to you reasonably inexpensively. Custom sizing is very common in this realm.

mchardo · 02-18-2009, 06:53 AM

Thanks for the responses. Right now, there is a 2'x2' opening this is just covered with a wooden cover. I would like to put in a 2'x4' glass skylight that will open so I can use the window to access the top of the roof. I will be putting on a new rubber roof down on this flat part this spring. So once I build this curbing it will all be covered with new rubber roofing.

I have been looking at many different skylights, does anyone know of one that would open like it is on hinges? I know I have seen transom windows that crank out and then can be released to open freely the rest of the way. I hope this makes sense. I just want to have as much space to get out to the top of the roof.

Thanks again for the help.

Scuba_Dave · 02-18-2009, 10:36 AM

You need a roof window - Velux name for it
I've never installed one
You would need to build a curb for it
Depending upon how handy your are might be easier to DIY

Quote:

The GPL roof window installs on roofs with slopes between 18.5° (4:12) and 55°

http://www.veluxusa.com/products/res...ows/topHinged/

AaronB · 02-19-2009, 10:12 AM

There are bubble hatched available precisely for this purpose, designed for flat roofs. I have a number if you would like it. Shoot me an email.