Expert: Bruce E. Johnson - 7/15/2009

Question
QUESTION: Bruce, since Sep 2007 you've answered many questions about a project I was then planning and am now actually doing.  First and foremost, your help has been wonderful and is deeply and sincerely appreciated!!!!
Basically, I am connecting two finished buildings, the main house and the carport/office, which are 5 1/2 inches apart. I know crazy, but I didn't do it.  I purchased this house in 2007 and saw the opportunity to add 1288 sq ft to the main house by connecting the two 2 bldgs and closing in the 25x27 carport (which already has a completely finished 25x25 room/office w/ its own HVAC on the far end).  The roofs on the carport and main house run in opposite directions.  I connected a ridge beam to the flat wall of the house and built a rafter valley roof across the carport roof. I have the connecting valley roof in place.  Woohoo! =o)

Now comes the hard, scary part, and my question.  The Roof on the carport is lower than on the house, and its edge is actually visible through and cutting across a double hung window in the main house on the common wall (that window will become my doorway to the carport/new family room).  Because the roof line is too low on the carport over the planned doorway, I need to modify 2 trusses in the original roof of the carport to create a higher stairwell ceiling over the planned 3-steps down into the carport/new family room.  I need to cut the 2 trusses back app. 5', which will not interfere with the "V" braces on those 2 trusses.  I basically need to cut the ends off the 2 trusses and cut a 6' section out of the end supporting horizontal beam to allow a higher ceiling over an app. 6' opening.  
1)    I know I can't leave these 2 trusses just hanging in space, so to speak.  I need to put headers in the carport attic to brace the new, cut ends of these 2 trusses.  I want to make sure I do this correctly.
I "think" I will need to put a 2x6x10 header across the 2 ceiling boards I cut back and a second 2x6x10 header across the 2 rafter boards I cut back.  Then add vertical supports at the cut end to create the end of my stairwell (area of higher ceiling).  I am unsure of the placement of these headers, and wondering if 10' long 2x6 headers are big enough and long enough to brace a 6' opening?  Do I need longer headers to extend past more than one uncut truss?  If so, how long?
If a lay a 2x6x10 across the top edge of the ceiling boards just short of where I am going to cut them, how best do I attach this header board to the 2 cut ceiling boards, and to the remaining uncut boards?  Brackets?
If I lay a 2x6x10 across the rafters just short of where I am going to cut them, how best do I attach this header board to the cut rafters, and to the uncut rafters?
Will this work to effectively brace the tops and bottoms of the 2 cut trusses?
2)    Along the 27' edge of the carport roof, the new 6' opening for the higher ceiling falls center of two 2 vertical, 6x6 beams that are 10' apart and which will stay in place and be incorporated into the interior design of the new family room.  But, I have to cut 6' out of the 6x6 horizontal roof support between those 2 vertical beams.  Nervousness!  Given that all 4 vertical 6x6 support beams along the 27' edge of the existing carport roof will stay in place, what do I need to know and do before cutting out a 6' opening in the top, 6x6 horzontal beam that supports the edge of the carport roof?

Hopefully you can visualize this and make some sense of it.  I am very much a rookie, am obviously totally unfamiliar with proper terminology, and have taken on this project with my 15 year-old son.  To me, cutting out the 2 existing carport trusses and top horizontal suppport beam is the most worrisome and nerve-racking portion of this project.  Your guidance, suggestions, advice, etc., would be most sincerely appreciated!
Susan

ANSWER: Hi Susan, has the roof already been built?  If not why not just have the truss company build you some scissor trusses or trusses with the necessary cutouts built into them?  That's what I would do.  If the trusses are already built, again you can have the truss company provide you with an engineered fix to give you the configuration you need.  In some instances they will even come out and do the work.   I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com

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QUESTION: Bruce:
I really, really can't afford to have any company do anything on this project.  That's the main reason we are doing all of the work ourselves.  I have to be able to figure it out and do the work myself.
Yes, the connecting valley roof over the main roof is already built.  Looks good too! =o)
My understanding from you way back when was, cutting the "tips," so to speak, off of two trusses could be done and wouldn't create a major problem.  It's my understanding this same type of thing is done when adding dormer windows and, although it must be done correctly, it does not require professionally re-engineered replacement trusses.  Please tell me I understand this correctly, and that there is a way for me to do this myself.
The main underlying roof has 14 trusses 2' apart, each spanning 26'. The roof underlying my valley connection being 32' x 26'.  I need to cut a minimum of 3' off of the tip of the 2 center trusses, 5' would be better.  The cut will be at least 2' beyond the scissors supports on each truss, and will not interfere with those supports.  As I understand it, as long as I don't interfere with the supports on each truss this can be done.  Please, please tell me I understand this correctly.
If I cut the 3' tip off; place a 2x6x12 horizontal support across each bottom beam and each top rafter, extending over 2 trusses on each side of the 6' opening created, and then; put a vertical support at the end of each cut truss (to square it off), will I be okay?
Please, please tell me there is a way for me to do this myself.
It may help to know, I live in the most rural of geographic areas.  The general rule out here is, if you can build it you can live in it!  Shucks, having a house of any kind attached to the ground out here is considered high class!  Plus, it's a minimum of an hours drive to anything, and I mean anything!
Please tell me you can help me do this myself.
Susan

ANSWER: Hi again Susan, I'm not sure what you ae calling "tips"..could you possible write back with a photo of the problem so I can visualize it better? If I can see your dilemma I can probably help you out.  Thanks, sincerely bruce

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QUESTION: Hey Bruce, loving my technical lingo huh? =o)  I knew I should have written that better. =o)  Sorry, I had been on the roof way too long in this heat yesterday to make much sense of anything.
If my son were here I could send you a photo.  Unfortunately he's not, and my computer skills are worse than my roofing skills!  Let's see if this helps?

What I'm calling the "tip" is where the bottom chord, or ceiling joist, and the rafter of the truss meet at the pointed end of the structure, or outer, bottom edge of the roof.  (The roof has a 1' overhang.)

The panel points, where the diagonal webs meet the bottom chord and top rafter of each truss, sit back well beyond what I need to cut out.  The web, or diagonal "V" supports, do not interfere and do not need to be modified.
I'm figuring the panel points were designed to carry and spread the weight on the entire truss. I need to cut the weight out on the ends of two trusses.  In theory, it would seem to me I would be reducing the load on those two trusses and, by leaving the diagonal web supports in place, I would be okay?
My plan was to add a vertical support on the new, cut end of each truss, running from the rafter to the bottom chord at the point where I cut them each off.  Thereby taking away the point, or "tip", and squaring off the end of the truss.  
This would allow me to cut a rectangle of the roof out and raise the ceiling in a 6' wide x app. 4' deep area where I have already built the new, higher valley roof over it.

My biggest questions come into play regarding reinforcement of the two shortened bottom chords on the two trusses I cut the "tips" off of.  Having cut the ends off, those two shortened bottom chords will not be sitting on anything!

My plan was to run a 2x6x14 perpendicular to the bottom chords, extending out and overlying 3 unmodified bottom chords on either side of the 6' opening.  I would also run a 2x6x14 perpendicular to the top rafters in the same manner.  Then, add vertical supports connecting the added top and bottom 2x6x14's at each of the 3 unmodified trusses on either side of the opening.
Will this work?
Your help, guidance and expertise is most sincerely appreciated!
Susan


Answer
Hi again Susan, take a look at the attached sketch I did and see if this kind of describes what you are planning to do. I don't know exactly how your trusses are configured but I think you will get the idea.  Write back and let me know.  I didn't show the vertical supports but I believe they would go from your support beam up..sincerely bruce e johnson