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-   -   I have a question on changing trusses, I am framing an attic room. (http://www.diychatroom.com/f19/i-have-question-changing-trusses-i-am-framing-attic-room-2123/)

wackerjr 03-26-2006 12:40 AM

I have a question on changing trusses, I am framing an attic room.
 
I have a question. I am thinking about framing a room above my garage. I currently have the W-trusses. I need to frame the trusses to look like the other home in my link.

My thought is if I take my existing trusses and butt 2x6's next to them, I can reframe the entire thing to work. I should note I have a beam across my garage that should hold the weight, you can see it in the pics.

the first 5 pics are of my home, the last 4 are of the trusses I need.

My thought is to basically rebuild the truss next to mine then cut it out accordingly. Is this possible? Or AM I shooting in the dark here? I can access the top of the walls, and balieve I can access to nail in the attic.

http://community.webshots.com/album/548913906SagQFN

My thought is to run the 2x6's all the way to the out side, and tie into the top and bottom board on the truss. You can see this on in the pic from the inside of my garage.

I hope can do this...
Thanks

Bonus 03-27-2006 01:33 AM

If I understand what it is that you are trying to do: cut the center of the "w" out of the existing trusses and 'replace' the structural integrity of the truss by adding more lumber so it looks like the trusses in the later pics? I wouldn't go anywhere near that without an engineer. You can't cut up trusses and assume anything about them afterwards, these are complex systems , look out.

wackerjr 03-27-2006 04:59 PM

Man after rereading what I posted the other day I must have been on something. LOL

Yes What I am trying to do is reframe the attic. The trusses I have are the w type, and I need to reframe it to look like the others. I have an engineer that could help me out. But I guess the question I have is this. Everything I have read says don't even attempt it with the W trusses. I see no reason why it won't work, but have had no experience with it. Does anyone know if it is possible? I believe that if I basically rebuild the truss, with the 2by6 lumber like the pic, and the lvl for the floors, I should be sufficent. Just trying to figure out if it is going to even be a possibility, before I go and spend the money on permits, plans, and an engineer. I really don't want to rip the roof off, I would like to do it all internally.

Bonus 03-27-2006 10:48 PM

The thing is you have a choice: You can rebuild as if you were stick framing the roof, which means larger members or smaller spans, or you can rebuild trusses. If you rebuild trusses you are going to have to come up with tension connections, so gangnails, plywood etc. Any time I've built trusses I've had to get gussetts both sides of the members to be able to get enough nails in to hold it together (it takes a LOT of nails), and if I've got what you're planning you will only have one side available. However, I'm sure it's possible, almost everything is, but you're going to have to get the engineer involved to find out which of many options is going to be structurally and financially optimal. Good luck, let us know how this goes.

redline 03-29-2006 04:51 PM

Did you have an architect draw up the design or was it an existing design?

The large support beam that is in the picture, is it in the center of the room or off center?

wackerjr 03-29-2006 06:24 PM

that beam is going to end up off to the one side of the room. so everything on one side will have no room over it, and the other side will be all room. I hope that sounds right?

I guess I should have mentioned that I planned on running on 16" centers instead of the 24" now. I guess I could just frame it up like you would without trusses. I guess my biggest concern is it possible to do without tearing the roof off? also if you look at some of the pics you can see how the trusses dip down on one side of the garage, this is the area I am most concerned with.

Thanks

whoops on edit, the plans were an existing that we modified, my garage had to be extended 5 feet, so they had to change the front hip on the house. SO that beam is inbetween the 2 car portion, and the 3 car portion. The other cross beam you see running the other direction actually supports a room above that portion of the garage already.

mighty anvil 04-01-2006 09:50 AM

The purpose of a truss design is to reduce the size of the rafter segments and ceiling joists (bottom chords) in order to save money and perhaps time. It seems like a lot of work to save a little but I guess builders love them.
As a general rule the more truss members in the center portion of the truss, the smaller the rafter and joist segments can be.

The new truss photographs appear to have 2x6 rafter segments and yours appear to be 2x4 which makes sense. If the spans are similar you probably can't make the conversion without adding 2x6 rafter segments. Rather than do that I would add 2x10's or larger rafters and forget the truss concept other than conventional knee walls and collar ties. (you will then be able to insulate the full rafter cavity.) Then cut the trusses out and throw the crap away. Sorry, but I just hate the damn things for the reason that people often eventually want to do just what you are describing. When they call me I never take the job; it's just too painful. Trusses are short-sighted nonsense in my opinion.

wackerjr 04-01-2006 04:09 PM

Quote:

Originally Posted by mighty anvil
The purpose of a truss design is to reduce the size of the rafter segments and ceiling joists (bottom chords) in order to save money and perhaps time. It seems like a lot of work to save a little but I guess builders love them.
As a general rule the more truss members in the center portion of the truss, the smaller the rafter and joist segments can be.

The new truss photographs appear to have 2x6 rafter segments and yours appear to be 2x4 which makes sense. If the spans are similar you probably can't make the conversion without adding 2x6 rafter segments. Rather than do that I would add 2x10's or larger rafters and forget the truss concept other than conventional knee walls and collar ties. (you will then be able to insulate the full rafter cavity.) Then cut the trusses out and throw the crap away. Sorry, but I just hate the damn things for the reason that people often eventually want to do just what you are describing. When they call me I never take the job; it's just too painful. Trusses are short-sighted nonsense in my opinion.

I guess I have not explained it very well, I can handle most any of these projects, but I have found so much information saying if you have the w trusses don't waste your time.

Basically what you described is what I want to do. I only posted the pics as comparison. I need to frame a room the same way. I am not going to try to redesign a truss, or try to build another.

I have thought about this more and here is my new Idea. Run (I don't know what the correct term for them are) the I-beam wood joists like in the floors of most houses. Then run 2x8 to the outside walls for the roof. but how do I beam the top inside? or what would be the proper way to do this................. I guess I am just going to have to go and pay someone to look at this for me and let me know if it is feasable.

mighty anvil 04-01-2006 05:17 PM

If you add I-joists to create a floor (and if the existing structure can support that load) and if you add 2x8 rafters (and they are big enough for the span and are properly tied to the intersection of the walls and I-joists) then all you need at the ridge is either a continuous board the same height as the rafter ends (1x10 or 2x10) or you can butt the rafters together and connect them with a plywood gussett plate. Ether method is usually allowed by code. There is no ridge beam needed if everything is tied together properly to form a stable triangle. Then you can cut the trussed where you need to since they are redundant. Most of this can be sized from manufacturer's tables or the building code and your lumberyard has that information. Sometimes they can even get an engineer's stamp for the particular system being added. The new subfloor also ties the floor joists together, and you can add rafter collar ties if there is room and kneewalls where the ceiling is below 5 ft. or so.

trader 01-21-2008 10:11 AM

Hello wackerjr vbmenu_register("postmenu_9744", true); ,
Did you complete your project?
Thanks.
J.

trader 01-21-2008 10:14 AM

Forgot to tell.
I'm thinking about to do the same. May be you can share your experience with us?
J.

gregzoll 01-21-2008 11:58 AM

It cannot be done, unless you take out the Engineered Trusses, and Frame it with 2x8 min (I would go with 2x10) for the floor, and 2x6 for the roof framing. Or just order trusses made for the purpose that you are wanting, which are framed for under spec's given to the build shop. All that you are going to do, is cause headaches later on down the road.

trader 01-21-2008 12:29 PM

Hello,
One thing I can't understand: why do I need to remove existing trusses if I'll install rafters (2x8)? After I put in place all rafters and all joists (2x10) I think I could just remove only part of existing trusses to open the necessary space.
Am I right?
Thanks.
J.

gregzoll 01-21-2008 02:35 PM

Due to the Trusses are engineered for a specific design, removing the W from the Truss will cause problems later on (ie sagging), unless you go back and either put in kneewalls and 2x overhead at the 8' headroom. Or just to make things easier, due to the truss is all 2x, create new framing, which as stated before, 2x10 for the floor, and 2x6 for the Roof Framing.

The key is to do it right the first time, and then you do not have to worry later on.

Kingfisher 01-21-2008 02:36 PM

From looking at the photos it appears to have a small area of slanted of ceiling and that the bottom cord is not resting on the wall? I think you are stuck if this is the case as you can not transfer the weight to the wall directly and the truss was not made to carry the laod you are planning. If I'm looking at the photo wrong please say so, other wise do not try this at all.


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