What kind of room can I get out of prefab attic trusses?

Started by SardonicSmile, November 14, 2009, 10:26:57 AM

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SardonicSmile

Im thinking about getting trusses like these:



In the 20x30 1 1/2 story plans, what kind of room (standing room) could I get out of these prefab trusses? I know stick building would get me more room, but I liked the idea of just lifting the trusses up there. I've heard you can get a good bit of room depending on how thick the wood is.

Any other advice on trusses?

MikeT

Just eyeballing it here:  with that set up you would have around 6 feet of headroom, maybe a bit more.  Assuming you go to a truss company or talk with a lumber yard where the folks might know something, they can tell you what the options are regarding maximum space within a truss.  I imagine you would also need to spec out the truss differently if it were going to be bearing a load on the bottom plate.  Now I will defer to the real experts here.....


Redoverfarm

SardonicSmile I put attic truss's over my garage from a regular truss company.  It was 26' wide and 44 feet long.  They gave me the option of a 5' knee wall or they could move it back to 3' knee wall.  That gave me the option of a 12' wide room vs. a 15' wide room.  I opted for the 12' because it is useless space at 3' (nothing would fit) and I will utilize the (kneewall to rafter tail) space for storage which was more valuable for me.

I have regular headroom below the collar ties.  Mine were 2X6 over 2X8. They are engineered trusses.

SardonicSmile

Thanks for the input guys. Sounds like i'll be able to get atleast 30' x 8' walking space, which is fine when you remember that the furniture can go up against the 5' knee walls and not take up much walking space.

rocking23nf

I didnt think trusses were meant for a room above. My trusses are 2x4's, if you stood on it, it would probably crack in half.


Don_P

Depends on the truss, I drive across a truss bridge almost every day. It'll hold concrete trucks and spans over 100'. A textbook truss is a triangularized structure that loads its members in compression or tension only. The modern metal plate connected wood truss is something of a hybrid between a truss and a frame and can take bending loads as well.  It's all in the design, an attic truss in my opinion is a modified queenpost truss. We've got a set of 26' 8/12 attic trusses coming next week the room above is 12'wide.
This was a 12/12 attic truss 24' span, cantilevered. The bottom chord extends out level to form the overhang, the top chord rises not from the wall line but from the overhang, this makes for more room above.


Just to show that dimension can vary in truss material, this is also a truss, the top and bottom chords are 8x10's. The trusses are spaced 10' apart.