I have an attic I'm considering converting to living space and looking at ways to increase light while also increasing head room. The current (skylight-less) roof has a slope and I'm wondering if I can install a bank of skylights, maybe raised up on a deck, to bring in some great views and increase head clearance below the skylights. I'm including a graphic showing the walking surface and the roof angle, along with a future raised skylight area. The stretch of walking surface in this area is about 15' long.

Attic schematic

Looking for people who have installed skylights in attics for the purposes of increasing head height/clearance.

If this is possible, wondering how I can make sure that rain/snow flows off the top side of the skylight. This would be especially important if I install a bank of skylights on a deck spanning the entire 15'.

  • You show the floor at 150". What's the wall height behind your little man? That's the truly important measurement.
    – FreeMan
    Dec 11, 2020 at 12:10
  • 1
    If you are going through the trouble of cutting out all those rafters (and the additional engineering and gusseting required to add strength) you should consider adding dormers or a gable and shed. Dec 11, 2020 at 13:02
  • @FreeMan it's not a good drawing. There's no wall there, the attic is open and an A shaped roof. The height of the ceiling at the apex of the roof is 102" or 8'6", which gives me a reasonable amount of space to get r49 for the top.
    – rajan
    Dec 11, 2020 at 16:34
  • 1
    I think that if you have the talent to cut out rafters, frame up an opening, and properly install, flash, and seal a skylight then you could do it. All the same basic tools and skills. Dec 11, 2020 at 17:46
  • 1
    Find and binge-watch about 5 seasons of This Old House from the early- to mid-90s. Long before the internet, that was all the education my wife & I had before we tackled building an attached garage on our hose. In 28 years, we've only had leaks where we couldn't get the furnace vent to properly seal through the flashing. It took about 2 years of fiddling to get that right. Your solution - don't put any holes in the dormer roof!
    – FreeMan
    Dec 13, 2020 at 13:11

1 Answer 1


The Code requires a minimum ceiling height of 7’-0” for habitable spaces, unless 1) it’s a slopped ceiling, 2) basement remodel, 3) bathroom or shower. (See ICC R304.1)

  1. Slopped ceilings shall have at least 50% with at least 7’ and slope down to no more than 5’.

  2. Basements can have 6’-8” ceilings in non-habitable spaces.

  3. Not more than 75% of a sloped ceiling in a bathroom can be less than 7’ if a space in front of toilet, sink, shower is 6’-4” high.

  • Thanks for the reply, can you explain which of my questions are answered by this answer?
    – rajan
    Dec 11, 2020 at 14:26
  • Depending on your situation, you’ll need to comply with the code required height dimensions. Currently it does not comply, as pointed out in item 1.
    – Lee Sam
    Dec 11, 2020 at 17:28
  • Item 1 only means that anything below 5' isn't counted into the calculation of square footage for the room, which isn't something I'm concerned with at all.
    – rajan
    Dec 11, 2020 at 18:09
  • The code doesn’t say not to count square footage when ceiling is less than 5’. It says habitable rooms can’t have spaces less than 5’ high. Maybe you could build a wall at the 5’ height. (If that space is only a hallway, storage space, closet, etc. then it’s not a habitable space. Add a desk, chair, bed, etc. in that space and it becomes a habitable space and is not allowed.)
    – Lee Sam
    Dec 11, 2020 at 21:51
  • Here's a good explanation of the knee wall issue, which isn't something I'm worried about (we will have crawl spaces and put in storage in most short ceiling areas) evstudio.com/…
    – rajan
    Dec 12, 2020 at 0:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.