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Modify rafters to open up existing dormer

7K views 12 replies 7 participants last post by  Nealtw 
#1 ·
Hello all,

I am finishing the upstairs of my 1 1/2 story. There is an existing dormer, that was sealed off from the rest of the living space. I want to open up that space and put in a window. In order to do that I have to cut through two rafters of the existing roof system. Basically what i want to do, is cut two rafters, install a header, and then add support studs to the header. See the image for details. Is this the proper way to do this, or what is best practice?



http://lydtansky.tumblr.com/image/85834952840
 
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#5 ·
Thanks,

The comment about the top plate, that is left from a interior wall that used to run along the room. it has no structural value, i just haven't removed it yet after i removed the wall. do i need to double up on the white angled ones you drew in? would they essentially become a valley rafter?
 
#6 · (Edited)
Thanks,

The comment about the top plate, that is left from a interior wall that used to run along the room. it has no structural value, i just haven't removed it yet after i removed the wall. do i need to double up on the white angled ones you drew in? would they essentially become a valley rafter?
Don't really know not an engineer. wouldn't be a valley rafter.
 
#7 ·
Go to the library and get a book on framing--dormers will be included--you need to double up the roof rafters on either side of the dormer ---as built the roof will sag---if you cut out the rafters in the middle--

Your floor (cieling joists) are not designed for carrying the roof load---
 
#9 ·
you want to use the full length original rafters either side of dormer and double them up then run your header across with a double joist hanger attaching them catching the rafters from there up to ridge . then you can fill in a rafter that works to the left of dormer if needed to, may need to be a double as well to sit under dormer wall if you are adding walls to the dormer...


so basically use the full length that is there for wall plate to ridge for your doubles then fill in back toward dormer with rafters if needed.
 
#12 ·
Hello all,

I am finishing the upstairs of my 1 1/2 story. There is an existing dormer, that was sealed off from the rest of the living space. I want to open up that space and put in a window. In order to do that I have to cut through two rafters of the existing roof system. Basically what i want to do, is cut two rafters, install a header, and then add support studs to the header. See the image for details. Is this the proper way to do this, or what is best practice?



Untitled: Photo
My setup is identical to this. How did you end up framing it? Do you have any pictures?
 
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