Truss construction

From an engineering perspective this truss system seems less than optimal to me. Other thoughts/obeservations??

Attic Truss1.jpg

IRC 2003 R802.3 says: Rafters shall be framed to ridge board or each other with a gusset plate as a tie. Ridge board shall be at least 1" nominal thickness and not less in depth than the cut end of the rafter. Therefore the left side is fine, the right side sucks. Oh, and I wouldn’t call this a ‘truss system’, that sounds like it’s an engineered truss and, in this case, it’s not.

In addition to what M. Boyett pointed out, it looks like the ridge board is pieced together. It looks like there is a butt joint under the third set of rafters.

Hard to tell what is going on here. Was there a structural reason for using the larger dimension lumber on on side or did they run out of the smaller dimension material and used the available larger stuff? If the latter is the case, I see no problem with it.

Also, there is no problem with the joint in the ridge board.

Again, hard to see the whole picture in the right perspective.

It appears that the roof framing is definetly stick built, and one side is roughly a 6/12 pitch and the other side a 12/12 pitch.

The 6/12 pitch would have a plumb cut of 6-1/2" and the ridge board of the picture would indicate it in proportion to be 2x8" and the opposite side of the roof would have a plumb cut of 10-5/8" showing 4-1/2" below the ridge.

Again the picture does no justice to all the relative variable factors of condition.
Based on what I deduce, the ridge board, although called out to be a minumum of 1", should have been a 1"x 12" to accept the proportional values of the plumb cuts.


Collar ties
rafter size differences
exact pitches
loading by area
wind uplift
amongts others.

Hope this helps.

Marcel :slight_smile: :slight_smile: :slight_smile:

Dang Roy, you must be interpreting that photo under Canadian rules.

Never mind, Canadian rules don’t apply in Georgia.

It’s hard to find 40 to 60 foot long boards at the local lumber store.:stuck_out_tongue:

Actually, I was born to throw a rock in Canada, and the ridge boards would have been of a 2"x? in liew of the minumum standard of 1" and the answer is no a ridge board does not have to be in one uninterupted length.

Marcel :slight_smile: :slight_smile:

Actually, I was referring to the wrong dimension of the ridge board, not necessarily the length…:slight_smile:

I agree Michael;
Sorry for the confusion in the quotes, I was actually trying to address a question downline from that. Still green with these darn computers ha. ha.

:slight_smile: :slight_smile: :slight_smile:

da nada, amigo…

I know Marcel, I am an Architectural Engineering Tech. and a Licensed Carpenter for almost 20 years.:wink:

Here’s a picture of me when I was younger. Arthritis prevents me from doing heavy rough carpentry. I do mostly finish and custom work now.:slight_smile:

Thanks, great call on the roof pitch, your right on. I don’t have a photo that shows it well, but the area exposed below the ridge seems to begin to split . I wouldn’t think the load would be that great. I recommended eval by an SE but wanted to get others opinion. Thanks!

Ok all you smarty pants, I realize they don’t make boards that long.:slight_smile: I was referring to it with respect to it being unscabbed, unsupported, etc. I was thinking that the load may not be transferred correctly along the length of the ridge and that maybe it could cause problems at the joint.

Perhaps the right side as in photo is the framing for cathederal ceiling. It may be larger rafters to accomodate the insulation and air space above, while the left side of the picture could indicate an attic space above a flat ceiling. Either way I don’t see a problem as evidenced by the photo.


I also, am cofined to a Fisnish Carpentry Level, and that is because, after 40 years in the construction bussiness, my body will not let me do more, and that is why today my focal point is to be the best Project Superintendent possible and let the younger bodies do the work under my guidance.

What you said based on the pictures supplied, is kind of speculation and I tried to explain why the construction practice is wrong in either case.
Some builders out there need more guidance or better books and experience to show them how it is suppose to be.
That is why I am still in the field. For one that is willing to learn, I will spend unterupted and personnal time to make sure he/she understands. The Principles and loggic behind everything you do is most valuable to the teachings that can be provided along with the guidance of good reference books for them to learn.

As inspectors, I believe you should note what you see and not have to necessarily have to explain why unless there is probable cause, that the issue might create a problem with your references or capacity in the Generalistic Inspections.

A wise man once told me that you talk alot on the inspection tours, and you write what you see and what it is. Well, something like that. ha. ha. Wouldn’t be surprised that you heard about him also.

Marcel :slight_smile: :slight_smile: :slight_smile:


I respect your concern about what you brought up, regarding the scabbing or splicing or the ridge board.

This procedure in stick building is normally for erection ease only, and has no structural value. It is there for the lateral stalbility of the rafters being installed one by one and assummed that the rafters are to be installed on both sides at the same time.

Since pictures on the Post are very hard to picture in 3-D, it is very hard to surmize a concrete conclusion.

Report what you see or concerns you and reccomendations of reference to a particular matter are always accepted by the client.
We are all here to help also.

Take care;

Marcel :slight_smile: :slight_smile:

How old is the house? I don’t see any comment as to age?