Hello - I am in the process of investigating expanding a room by taking some space out of my garage. This entails moving a wall about 2.5 feet into the garage to gain this space in a mud/laundry room. Above the room is attic space (which is easily accessable). My concern is that the current placement of the wall may be bearing some of the load of the roof trusses. Of course, I can always put a header where the existing wall is and then move the wall, but if I can do without, that would be preferred. I have contacted the truss company and they have faxed me diagrams of my trusses from their files. The problem is, I don't fully understand the diagrams. Hopefully someone here can answer my questions:

1. There are many measurements on the diagrams in the form "x-y-z" where x, y, and z are numbers. What are these numbers exactly?

2. How can I tell if the wall under the truss is load-bearing by looking at the truss diagram.

3. If I were to scan an image of one of the trusses, would someone here be able to make any sense of it?

Thanks,
Rob

Yes, please scan them.

Thanks - here is a JPG image attached. Let me know of you have any questions.

I am wondering if the line along the bottom of the truss (it has 44-0-0 just above it) with the little symbols means anything (three symbols, look for red arrows). The symbols happen to be where there are walls now. Does that symbol mean "Bearing wall must be here" or something like that. Also, what do the numbers with green arrows mean. Finally, how can the pitch be 8/0? Image below:

Thanks,
Rob
http://home.comcast.net/~rdmkap/out.jpg

The line on the bottom is a dimension line, it is locating the vertical members and where the bottom chord will be spliced as they can't get a piece of lumber that is 44 feet long. The red arrows must be where the existing walls are now, if you are going to change that you should have them adjust and get a Structural Engineer to take a look at it.

The green arrows at 13-6-0 is a dimension - 13 feet 6 inches. The pitch is 8:12, not sure why it reads 8.0 / 0.0 at the top. The ST numbers are the splice plate sizes and gauge (ST20-3.0x4.0 = 20 gauge - 3 inches x 4 inches)

Is the wall under the ends of the truss or in the middle of the truss?

I believe it bears on 3 points, ends and near the middle at a bearing wall.

Thanks. I was hoping that there was a way to tell how long the truss can span before needing a load bearing wall, but I guess form what you are saying, there is no data on this diagram that would answer this question without an engineer looking at it. I was hoping to avoid that cost if I could.

Rob

Yes - it does bear on three spots - right where I have the 3 red arrows. I was hoping to move the middle wall about 2.5 foot to the right looking at my diagram.

Rob

That should be possible, the truss manufacturer will need to adjust but moving the bearing point to the right only centers it up more. I don' tthink you need a Structural Engineer unless it is required for your permit.

Thanks amricca - another question - what do you mean by "the truss manufacturer will need to adjust"? This is a remodel, so the trusses are already built in the configuration you see. Are you suggesting that they would need to comeout to the house to add more members to the existing truss?

Rob

OK, I didn't know you had them already. The middle wall is a bearing wall so you can't just move it, they planned on it being there in their calculations and it may affect other parts of the roof framing. You can add a header and posts if you want the space below open but that one would require some engineering for the header and post sizes and spacing. Do you have to move that wall?

Nope - I don't have to move the wall. The wall separates my mud room/laundry room from the garage. The room is quite narrow now, and when the door is open, it blocks the person behind it from moving into the next room unti lit is closed again. This makes thigs less than ideal when multiple are coing or going. So basically, I would like to add a few feet to the depth of the room to eliminate this congestion, and to split the laundry room/mud room into two separate rooms. I have considered a header. Since I want to minimize the height of the header, I would plan on using a steel I beam. The beam only needs to be about 13 foot long, and I am guessing 3 2x4s or 2x6s should be enough to bear the load on both sides of the beam. I have access to roof jacks, so I can easuly support the trusses when I remove the existing wall and put the header in place. Your thoughts?

Sounds like a good plan. You could use tube steel columns to support that beam too, might be stronger than 2 x 4's.

Thanks for all your help and suggestions. I plan on doing this legit, so I have an instector coming over to look at my trusses, plans, etc. The city said he would know if my plans to use an I-Beam and support it are to code and strcturally sound. I'll let you know how I make out.

Well- definitely load bearing. The city inspector came out and found an orange "Load Bearing" tag under the insulation right on the truss where it meets the wall. I called the truss company and asked if I could pay to have an analysis done to see what I could do to shore up the trusses, and they said no - they don't do that. So now I need to figure out who to talk to about the specs for a header. I'm guessing most lumber yards will be able to help me out there. Any thoughts?

Thanks,
Rob

If the lumber yard can't help you a local Structural Engineer can.

You would think that, wouldn't you. I am surprised at how many local Structural Engineers either don't work residential, or tell me that it will be very expensive for me to hire them and recommend that I don't make the modification at all. I would have thought that in this economy, people would be jumping at the opportunity for business, but I have not found that yet, at least with structural engineers. I'll call a lumber yard and hope for better luck.

Thanks again!
Rob

Steel suppliers usually have a structural engineer on staff, you might speak to one if you are going to use a beam there, they may be able to help you out.