setting trusses with only 2?

Egon · Feb 29, 2004

Sounds just like I do it. Splicing on a truss is just plain a pain and not the best way.

Egon

mopower440 · Feb 29, 2004

Wait a minute guys, you mean i can just let the lumber run and scab the 2x4's together wherever they need to be joined, even if its between the trusses? kinda like plywood sheathing a roof and connecting the sheets with those little connector? I wish i would have known that, i was thinking about that today because i was tired of cutting and waisting so much lumber just to get them to break on the trusses..so how do they need to be scabbed together, just use a short peice of 2x4 underneath the spot where the 2x4's will be joined together, how long should the scab board be and what type and how long do the scres need to be? Is it still good and strong like this, remember, the trusses are on 4' centers..? This sounds like a plan!! Let me know the details! /forums/images/graemlins/laugh.gif

Glenn9643 · Mar 1, 2004

"so how do they need to be scabbed together, just use a short peice of 2x4 underneath the spot where the 2x4's will be joined together, how long should the scab board be and what type and how long do the scres need to be?"

Chad,
If using 2x4's I would use a 2' scab underneath and put two 3" deck screws on each side of the joint, one near the joint and the second near the end of the scab. Predrill the holes through your purlin so the screws hold tight or use a c-clamp to hold them tight and just set the screws that way.

rockinmywaypa · Mar 1, 2004

I am going to have to disagree that this can be equal to hitting a truss. Standing on this joint you are saying that the screws are going to be as strong as gravity on the truss, I wouldn't trust the screws over the life of the building.Looking up from below it is going to look scabbed which makes it look like corners were cut elsewhere. If you have a 2ft overhang on the gable that you start with then start with a 10 ftr and the end will hit the 2nd truss change to 16 or 12 and you will continue hitting the trusses. starting with 10 then 14 then 6 then continuing up the slope in order guarantees joints alternating on trusses and no slowdown to cut scabs clamp or drilling screws. Plus it will end up looking like it is right.

Glenn9643 · Mar 1, 2004

To each his own.

mopower440 · Mar 1, 2004

is it safe to put your weight on these joints scabbed together? also, do i screw the screw from the purlin into the scab board, or from the scabboard into the purlin?

Glenn9643 · Mar 1, 2004

Generally you could put your weight on the 2x4 two feet from the truss without any "scab" support due to the stiffness of the 2x4. It may give more, but shouldn't break unless it has a big knot. The two screws on either side of the joint spread the stresses out more and provide a lot of strength. True, it's probably not as strong as a solid timber, but over a four foot span I have found it to be plenty strong enough. I prefer to put the screw through the purlin into the scab board, because occasionally the screw will drive until the head is below the surface and with 3" screws could result in te point of the screw rubbing your metal roofing if driven through the scab upward into the purlin.
We aren't concerned with any snow load in this area, and I've gone to using 1x4 for purlin, splicing as above. This has provided plenty of support, but you have to watch for knotty places when you step with trusses on 4' centers.

mopower440 · Mar 1, 2004

well the only problem with doing it this way is that i will have to hope the breaks are exactly in the middle ofthe trusses, most of them seem to be about 3/4 between them..

TBAR · Mar 1, 2004

My brother, son and I put these 30' x 2' steel trusses into place with out power equipment. Not the safest way to do it but we got it done.

http://community.webshots.com/photo/43399132/43400790VmJCWL

1) We welded a pin vertically at the top of the pole and passed a rope around it.

2) We put two extension ladders up on either side of the first pole and wired them together at the top.

3) A rope was passed around the pin and down to the truss. While two of us lifted the truss a foot or so at a time my son would take slack out of the rope and hold the truss in place while we rested and climbed the next rung of the ladders.

Don't flame me. I don't recommend doing this. A front end loader or forklift would be the correct way to do this job.

TBAR

mopower440 · Mar 1, 2004

The ting i really hate about splicing on a truss is that the truss is only 1 1/2" wide as it is, so when splicing, your nailing each purlin right on the very edge of the truss, with 4 nails at that, seems like its not going to be secured that well because of the nails driving in so close to the edge of the purlins and the truss, i hated it yesterday each time i did a splice like this, makes me cringe..