Method to Plumb Trusses

[WI/MI Border]

A friend helped me lift and secure 13 trusses and the gable (drop) trusses. 24" OC, 24' long, 6/12 pitch.

The bottom cord is straight and true (24" oc) along all 13 regular trusses. I checked for plumb on all 13 and though I used steel truss braces for spacing (two rows about 4' from the peak) the peak is out of plumb as much as 1" (see below). Fortunately they all lean slightly to the west. Contributing to this, I think, is the steel bracing. It could be that the steel bracing was installed incorrectly as some of the "teeth" didn't imbed into the truss as much as it should have. Though I think warping of the trusses are the main culprit.

My gable ends are plumb. They are braced from the highest point of the gable web to the bottom cord of the truss two trusses in. Starting on the west end the next 13 trusses are approximately the following amount out of plumb at the peak, mostly leaning west except for three which are plumb. This was an "eyeball" estimate but close.

1/4", 1/2", 3/4", plumb, plumb, 1/2", plumb, 3/4", 1/4", 1/2", 1/2", 1", 1"

My friend suggested that I pull all 13 trusses as one unit with a strap. I'm not sure if I want to approach a fix this way since they vary in distance out of plumb. I'm curious if there is a better method. The height of the truss from bottom to top cord is just over 6' so a 1/4" in six feet is not too bad but with almost all of them leaning west I thought it was a good idea to correct as much as I can.

I have yet to measure the total peak distance from gable to gable. However, if that result comes out to 28' (design) would cutting/installing individual bracing at or near the peak between trusses be advisable? Or would you suggest bracing the peak with long 2x4s premeasured for 24" OC spacing and attached under the top cord?

Thanks for the advice, Tim

 

[Firstram]

Start with a plumb gable and move the trusses into alignment as you sheath the roof. Laying out 24” centers on the plywood and moving the truss into place is standard procedure.

 

[firebirdparts]

You bend them to where they are supposed to be, and in fact you might have to do that to get the roof on.
like firstram says its more definitive to let the sheeting show you. If you're using a metal roof that might not happen.

You have to respect the fact they both bend and lean. I am a fan of using 2 by 4's like you mention. If you get some points on the top and bottom in the right place directly above and below each other, that'll be plumb, but getting the top exactly where it's supposed to be in space is the critical part.

 

[jack stand]

Those metal spacers will throw you off layout. It's much better to mark up a 12-16' 2x4 with your layout for your temporary bracing as high up as you can reach from standing on the bottom cord.
In no way would I remove what you've done. It can be corrected.

 

[WI/MI Border]

Those metal spacers will throw you off layout. It's much better to mark up a 12-16' 2x4 with your layout for your temporary bracing as high up as you can reach from standing on the bottom cord.
In no way would I remove what you've done. It can be corrected.

Thanks all.

By "... remove what you've done..." You mean don't remove the steel spacers? They hold the top cord very firmly. I'm not sure fighting them to move the cord would be a good idea during elevated work but I have not tried anything like that.

 

[Skooterj]

I just used the factory markings on the OSB to plumb them as I moved up from the bottom.

 

[jack stand]

Thanks all.

By "... remove what you've done..." You mean don't remove the steel spacers? They hold the top cord very firmly. I'm not sure fighting them to move the cord would be a good idea during elevated work but I have not tried anything like that.

No, I thought someone had advised you to start over.
We've had trouble with the metal spacer but you can correct it with the sheathing by marking the correct layout (usually mark 2' 4' & 6') on the top edge of every sheet then when you're struggling fighting the clips to line up to your marks, rip those fxckers out and continue to the peak.

 

[WI/MI Border]

Thanks... That's what I thought you meant. I'm going to measure the peak at the gable ends today and determine if they are close to 28'. They are both plumb. I'll start at the front of the garage and measure across making adjustments and anchoring with 2x4 bracing pre-marked with 24' centers.

Waiting until the sheathing is being installed will work. I just feel more comfortable correcting them before I get to that step.

 

[Kaizen]

did mine solo so i screwed 22.5" 2x at midway up truss and on the sides of the top metal plate. Mine was 24" on center so that gave me the right spread without much measuring. I put the 2x on before flipping up but you could do it now. Nice to be perfect but even after you plumb all of them they will move on you so when you put sheathing on use bar clamps to pull them. I had a few that bowed even though my spacing was good.

 

[Firstram]

Thanks... That's what I thought you meant. I'm going to measure the peak at the gable ends today and determine if they are close to 28'. They are both plumb. I'll start at the front of the garage and measure across making adjustments and anchoring with 2x4 bracing pre-marked with 24' centers.

Waiting until the sheathing is being installed will work. I just feel more comfortable correcting them before I get to that step.

It’s not worth the effort! Just adjust the framing to the sheets, and run with it. You can make them perfect as you go.

Don’t overthink it!!!

 

[WI/MI Border]

Haha, that's my middle name... OverThink! I managed to pull them all plumb but I'm sure I'll have a pipe clamp handy when sheathing for the expected curvy truss.

Adding sub-facia work then on to sheathing, underlayment and shingles. Making slow progress...

 

[CraigStu]

It’s not worth the effort! Just adjust the framing to the sheets, and run with it. You can make them perfect as you go.

Don’t overthink it!!!

This is my experience too. You kill yourself trying to make the trusses 1/64" perfect and then still need to pull/push them a bit so the sheathing edge is centered on the truss. PS don't get carried away on nailing your spacers or whatever. Nail them w/ max 2.5" nails to the bottom of the truss. Remember you may need to knock them loose from above to get that edge placed right. If you think about it, the strength added by a well done roof to the entire structure is very important. Worse case I'd rather have a slightly parallelogram roof where all the edge joints are perfect than a perfect rectangle.

 

[andyvh1959]

When I built the roof on my 24x28 shop (by myself) I plumbed the first truss using a four foot long level against a staight 8' 2x4 I attached to the truss. Checked both sides for plumb on the 2x4, then braced the 1st truss. After that I installed each next truss to the previous, checked with the 4' level. I too used long 2x4 to set the trusses on 24" spacing instead of the metal spacing material from Menards. As I put the OSB on it confirmed the truss alignment.

 

[NUTTSGT]

Haha, that's my middle name... OverThink! I managed to pull them all plumb but I'm sure I'll have a pipe clamp handy when sheathing for the expected curvy truss.

Adding sub-facia work then on to sheathing, underlayment and shingles. Making slow progress...

 

[KenC]

This is my experience too. You kill yourself trying to make the trusses 1/64" perfect and then still need to pull/push them a bit so the sheathing edge is centered on the truss. PS don't get carried away on nailing your spacers or whatever. Nail them w/ max 2.5" nails to the bottom of the truss. Remember you may need to knock them loose from above to get that edge placed right. If you think about it, the strength added by a well done roof to the entire structure is very important. Worse case I'd rather have a slightly parallelogram roof where all the edge joints are perfect than a perfect rectangle.

The red part is why one small pocket in my nail apron has duplex head nails in it! Use whatever length
size you want and nail tight. The second nail head is always available to allow adjustment.

 

[CraigStu]

Love that Ken. I must have seen them somewhere before but I sure forgot about them. Thanks for the reminder.