Rafter splicing

Im curently fishing thru my book about rafter splicing. Anyone know a specific section noting this?
They had used pieces to splice the 2xs where they connected to the upper truss.

The roof actually bounced on this one when I walked on it and im not a big guy.
New construction BTW:D


Sean, I am having a hard time seeing the whole picture.
Are those piggy back trusses I see and the splice is to the main truss?

The members look small (are they using all 2x4s?) and you say that it was bouncey. What are the spans for what size members (probably SPF)? Also, the on center spacing looks off. If it is new, they should be able to back up the job with truss/roof framing engineered paperwork.

Your pictures show what a mess this is. Recommend further evaluation and move on.

Prety much what I did. Yes 2x6 and 2x4.
Marcel and I chatted about the issue and plans being reviewed were mentioned.

The roof was very bouncy. One you notice imediately when you get on it.

I will do an alligator splice with 3/4 plywood glued and nailed 2 - 4 inches apart. The plywood extends 4 ft past each end of the splice. I also put a brace below the splice.

From the limited pictures I see its not correct…splice are too short and nailing pattern is wrong.

Looks like you have trussed spliced…need engineer letter.

Pic 3 simply looks like transition from trusses to stick framing.

Agreed…looks like modified trusses.

First, both the connection to a truss and the extra load imposed on the truss must be designed and approved by an engineer.

Second, proper installation of the conventional framing portion can be determined through standard framing tables. Do you know the standard load design for your area?

Splices to conventional framing simply require the same size lumber with staggered nailing.

Are those trusses spaced 2ft ? If so, where are the h-clips.
Could you tell if the bounce was in between trusses (sheathing bounce) or actual rafter/truss top chord bounce?

Per IRC Table R503.2.1.1(1), you can span 7/16" sheathing 24 inches w/o clips. You can span 15/32" sheathing 28 inches w/o clips. You can span 19/32" sheathing 32 inches w/o clips…

I wouldn’t be calling out the lack of clips unless I was sure of the code.


Unless the plans call for clips which most tract home’s that use roof trusses do.

No clips usually means no spacing between panels also.

On second look the OP’s pictures show some clips there but some are displaced.

The clips are there in Seans Photos. Just hard to see.

OSB panels square edge should always have or get the H-clips just for the sake of self spacing.
It also helps keep the panel edges together. As we all know the future could bring high moisture in the attic and soften up the sheathing.
We see it all the time.

T&G sheathing is the best roof sheathing up here. :slight_smile:

Clips were present.

No need to measure, though the data does help in some cases. . If the roof bounces like a trampoline, I know its wrong.

Not true… nailing is often two rows of 12d-16d at 2 - 4 inches apart with the splice having a certain length in relation to what is being spliced.

“Often,” not “always.” The same applies to my statement. You are correct about length requirements.

My point was that there are no “engineering” requirements for conventional framing.

"The roof actually bounced on this one when I walked on it and im not a big guy.
New construction BTW:grin: "

a good reason to look in the attic before walking the roof. I hav seen too many bad items , like one roof had an area that was missing sheeting about 1" x 16’ if i had stepped there, bad news. From inside you could see tar paper and from the outside it looked OK.

My info comes from dealing directly with engineers when making repairs… every letter they have provided for the repairs I have done have always been 2 - 4 inches apart regardless as to which engineer I have deal with.
I know (or have been told) that the diameter of a 16d nails has 200 lbs of holding power per nail…which would explain why they want us to nail the crap out of it…that or they have stock in the steel industry. :wink:

While no engineering requirement may not be specifically stated, basic building / engineering principals do apply. I have been framing since 1978 and we always did alligator splices with 3/4 plywood glued to each side and nailed as previously stated; we still braced under the splice. Probably over kill but it beats the basic 2"x6"x2’ boards I often see sistered next to the splice. :shock:

Framing is probably one of the few areas that inspectors really fail to check diligently yet if missed you can be talking some serious consequences.

Jeff H., I have done framing to and I have seen many abortions from delinquent framing contractors also.
I have done repair splices like you mention, but that was mostly on engineered framing jobs.

I think what Jeff Pope is referring to is the fact that conventional construction is recognized in some areas as a prescriptive method of wood frame construction which does not require engineering design and analysis.
When that occurs like in this area, you can see about any version of rafter splicing imaginable.
Now whether they are satisfactory or not depending on the installation at hand, is a call that only an engineer would know or a qualified framing contractor experienced with structural members in conventional framing. :slight_smile: