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Trusses is #2 grade SYP okay

55512122's picture

I have a choice in floor and roof trusses, one company builds with #1 grade southern yellow pine in the top and bottom cords and the less expensive companys trusses uses #2 grade SYP in the top and bottom cords. None of my trusses is over 22ft in length.

(post #89561, reply #1 of 15)

You get what you pay for.  #2 lumber is fine for truss building, I would think #1 would be more for an appearance grade for exposed trusses.  If it were my own house, I'd probably go with the company that used the #1. If they choose to use a better grade of lumber, they probably care more about better design and workmanship. Could be the difference between a flat ceiling and a wavy ceiling.

918 Contracting - Residential Construction

(post #89561, reply #2 of 15)

Lumber grades reflect the number of knots, defects and structural strength in each board. Ask your dealer for a grade description book or a fax from a mill's grading will amaze you as to what is allowed in each grade.

No.2 southern yellow pine grade allows for large knots to the extent of weakening the board.  It allows for more than one large knot in a board.  End splits are also allowed for a total of not more than 20% of the length.  Staightness and quality of grain is not a critical factor in #2 SYP. So a board can be as crooked as the runner on a rocking chair and sill be a #2!

Ten years ago grading rules for #2 were of higher quality and therefore we used and sold a large amount of #2 that was really very nice. BUT over the last seven years we have changed our specs to #1 SYP as the #2 became poorer and the point of being embarrassing to deliver to the jobsite and ask a good contractor to install.  Even walk in  DIY'er began shunning #2.

There is no way in todays lumber market that I would allow a truss system made from #2 SYP to be installed on a structure....not even a garage.  Warpage, twisting and possible loss of structural integrity over time  due to attic heat baking the lumber.

And be advised.....even #1 stuff  can have its problems, but far less than #2.

Don't skimp on this important part of your stucture..........................Iron Helix

.......Iron Helix

(post #89561, reply #3 of 15)

SYP #2 has been the bread and butter of the truss industry for 20 years in this area, and much of the U.S. No way I would want to pay for an upgrade for trusses that are only 22' long. I would venture to guess that 90% of the trusses built in Illinois have #2 SYP in them. It's what we used in the trusses for my own house.

I'd don't know what kind of burr Iron Helix has under his saddle. Grading rules haven't changed to my knowledge since the 50s. And "Attic heat" doesn't degrade the strength of lumber. (Except some kinds of fire retardant treated lumber)

I would be more concerned about the reputation of the truss company. Using #1 lumber doesn't guarantee good workmanship. The guys who build the trusses should cull bad lumber instead of putting it in the trusses. Every plant gets good and bad loads of lumber.

Ask contractors you know who've dealt with one truss company or the other for a long time what they know about the company. They should be able to give you some good feedback.

What part of the country are you in? I know people in a few areas of the country and might be able to make a recommendation.

Truss Designer Extraordinaire

(post #89561, reply #4 of 15)

Boss:  I have 25 ft ceiling/floor trusses that appear to be #1 SYP.  It is harder than a brick and has no knots to speak of.

Question:  They are suspended from their top chord, so they have a short tail at each end where they come to a wall.  That short tail is warping/twisting in a bunch of places, and is going to cause me a real pain in the hemmorhoids when it comes time to wallboard in a few weeks.  What to do?  I have some ideas, but they are all a pain to accomplish.


Don Reinhard - The GlassMasterworks - If it scratches, I etch it!
The GlassMasterworks - If it scratches, I etch it!

(post #89561, reply #5 of 15)

The only solution I know of is to scab some lumber along the side of the floor truss.

Or - If you're framing a stud wall inside the concrete basement wall - You might be able to pul the ends down and nail them to the top of the wall to hold them in place.

Truss Designer Extraordinaire

(post #89561, reply #7 of 15)

Boss:  The bottom chord ends are below the top surface of the wall by about 6 inches. Remember, these trusses are supported by their top chord.  I only wish the ends were warping up!  Then scabbing along them would solve all my problems.  Unfortunately, these problem boards are twisting  and bending DOWN!  I'dlike to cut them off a few inches from the last connection point along the bottom chord and then scab a 2X4 to it.  These ends contribute nothing to the strength of the truss, since they just stick out into space.  They are about a foot long.


The GlassMasterworks - If it scratches, I etch it!
The GlassMasterworks - If it scratches, I etch it!

(post #89561, reply #9 of 15)

Does the end of your floor truss look like the attached picture?

If so, you're right - The end sticking out past the plate doesn't really serve much of a purpose. You can cut it off just as long as you don't get into the plates at the first joint.

But check with your local building inspector if you have one. Some of them get pretty sticky when you cut trusses. If you have any doubts, ask the company who built the trusses.

Truss Designer Extraordinaire

floor_truss_end.jpg7.25 KB

(post #89561, reply #6 of 15)

Boss.....................sorry no burr under my saddle.  But  I should qualify my statement about #2 statements refer to only #2 grade SYP, which is what is shipped for standard home building. not for truss fabrication.  

The #2 SYP that is currently found in the locally made trusses are of a #2 SYP Dense KD  or #1 SYP Dense or a Select Structural Grade, not #2SYP    There have been in the past truss companies utilize plain #2 SYP to gain a $ advantage in the market.... and that is my concern. 

Since #2SYP can be purchased "stabil-dry" ( still sort of wet )any trusses constructed of same may be subject to extreme warp in the drying heat of an attic-------hense possible structural degregation as members of the truss twist from the nailer plates.  

Been burned a time or I watch closely.

Best regards..............................Iron Helix

.......Iron Helix

(post #89561, reply #8 of 15)

Never heard of "stabil-dry" lumber. Maybe that in itself is the problem. Everything I've seen going into a truss if KD MC19. I think they're required by the Truss Plate Institute to use MC19 or drier.

I've never heard of lumber twisting enough to pull plates loose on a truss.

I see your profile says you're from southern Illinois, so you aren't that far from me. Who do you buy from? Jesse B. Holt? Precision Design? I was thinking there was another one near Mt. Vernon, but can't remember the name of the place. We don't sell much south of I-70, except in St. Louis.

Truss Designer Extraordinaire

(post #89561, reply #13 of 15)

Southern Truss is my preferred provider.....................they are GOOD!!

The problem of price/ material undercutting came from small upstart companies  wanting to enter the market.  Most have been from small towns in rural Indiana, Kentucky, Tennesee & Missouri.---and give you a book and promise a good quote and soon disappear. But in the interim these trusses have crept into a job or two as the owner supplies his own materials.  It seems that "pennywise is often $ foolish" as the local contractors/carpenters catch the rap for lower grade materials in trusses.

I would agree with the discussion admonishing the use of a reputable truss manufacturer that fulfills the computer engineered truss plan as per spec. in order to avert any potentially subgrade products.

The average "Joe' doesn't have experience to make such judgements or read the drawings so it is important to pick a source that is honest and reputable.

Sometimes that is a tough assignment.          Hence this discussion format.

....................................Iron Helix

.......Iron Helix

(post #89561, reply #14 of 15)

I've heard of Southern Truss, but don't know anyone there or know anything about their reputation. Glad to hear their quality is good - That's a problem in this area. (Even with the company I work for)

As for a "truss manufacturer that fulfills the computer engineered truss plan as per spec" - They all do that, or they'd be out of business pretty quick. With liability laws the way they are, if you deliberately build trusses wrong the lawyers would have you for lunch.

Truss Designer Extraordinaire

(post #89561, reply #10 of 15)


That's an interesting point you brought up about #2. The sheetrockers had to add a few shims here and there under my trusses made from #2 Hem-Fir. I wonder if #1 would have resulted in less warpage.


(post #89561, reply #11 of 15)

The important thing is that the engineer who designed the trusses used the structural numbers in the calculations for the actual grade of lumber used in the trusses -- or really, that they made the trusses from the material that the engineer specified.  It doesn't matter what material you use, provided that you design using its properties.


-- J.S.




-- J.S.


(post #89561, reply #12 of 15)

"....the engineer who designed the trusses..."

Engineers don't design trusses. People like me do.

(Hope you can sleep tonight)............(-:

Truss Designer Extraordinaire

(post #89561, reply #15 of 15)

> The sheetrockers had to add a few shims here and there under my trusses made from #2 Hem-Fir. I wonder if #1 would have resulted in less warpage.

Probably not.  Out here we only have doug fir, and I buy what looks good a few weeks or months before I need it.  Then I stack and sticker every piece to dry.  The grade has nothing to do with what the final shape will be.  I've seen Std&Btr stay straight while SelStr turns into a pretzel.


-- J.S.




-- J.S.