Spliced roof rafters

[lfoster]

This home is new construction with tile roof. The roof rafters are 2x8 on 16" centers with 2x10 ridges. Several roof rafters have been spliced in a 'v' pattern near the roof ridge; several have a plywood scab brace on the side, but several do not.

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\
\ rafter splice -
/ forgive the crude 'drawing'
/
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Will post pic', but it is hard to see.

[jlybolt]

Ridge boards are also spliced in a similar manner. If the rafter has a to span a long distance they have to splice it sometimes. I dont like the installation of the purlin. Its looks like it was laid on its side instead of the trailing edge and should be the same size as the rafter its supporting.

[jlybolt]

From my understanding Some areas may required engineer to design the splice. Im interested to see others replies to this post. The best place to make ths splice in my opinion would be over a support (purlin)

[lfoster]

I was curious too. The splice was in a 'v' pattern. Some had plywood nailed on the side of the rafter to strengthen; others didn't. The construction was heavier than most, 2x8 and 2x10, but the roof was tile, too. The builder is an independent, not the average neighborhood.

[Richard A. Hetzel]

It's hard to understand the whole roof framing system (if there is one) from the photograph. Generally speaking, rafters cannot be spliced. That single 2x4 is not exactly enough to function as a beam. If I were an inspector, I might write something like "Roof framing is unorthodox, and an architect or structural engineer should be consulted to verify its adequacy":

[jlybolt]

Linda, you may have to resummit the post. For some reason post under some catagories get less hits than others. Usually newer post do better.
Good luck

James L.

[afrost]

often if a rafter needs to be spliced because the length is too long for a single full span, then it would be doubled-up. that would be the cautious way to do it in the field.
it was not designed by a professional to be built like this. consulting a structural engineer (not an architect) would be advisable.

[Richard A. Hetzel]

Sorry, but there is no reasonable way to splice a rafter and still maintain structural integrity. and this is something every architect should know. Very long rafters require premium extra-length lumber, or intermediate supports. otherwise a truss should be used.

[homebild]

Richard Hetzel is correct.

There is no reasonable way to splice rafters and splicing rafters constitutes a serious building code violation.

Not only should any structural engineer or architect know this, so too, should every builder and code official.

[jlybolt]

Could you tell us about this code that its violating? I would like to know so I can reference it.

Thank you

[homebild]

Originally Posted by jlybolt

Could you tell us about this code that its violating? I would like to know so I can reference it.

Thank you

Since Texas uses the International Residential Code in most jurisdications, you can view Chapter 8 of the 2000 through 2006 versions of that Code to help you understand proper rafter construction techniques.

But I'll give you a hint:

Try section R802.6 of the 2003 IRC or 2006 IRC:

"The ends of each rafter or ceiling joist shall have not less than 1 1/2 inches (38mm) of bearing on wood or metal and not less than 3 inches (76mm) on masonry or concrete."

Unless each end of the 'splices' of rafters are supported at the 'splices' (as Richard Hetzel rightly stated a few posts back) by a structural support at least 1 1/2" wide under each end... these ends 'spliced by plywood' do not structurally 'bear' on anything....only 'air'...and therefore do not meet code minimums.....

Therefore, the rafters illustrated in the photos above.... violate IRC Code.... and remain illegal under any circumstance where the IRC is employed.

[rwiley]

When I was working in Florida as a roofer when a reroof was pending, existing shingle and new to be cement tiles there would be engineering and modifications done to bear the new roof loads.

[Kenton H. Shepard, CMI]

James is right, that type of splice is typically used for ridges, and it's a very sophisticated, strong splice if done correctly... for ridges. This is not a great framing job. I'd recommend a contractor evaluation, and as a contractor I'd add a plywood gusset to any rafter spliced like that. I'd gusset both sides, use glue and a lot of nails. It's probably OK... but maybe not and who carries the liability if it's not?

The purlin is badly done and should have been a 2x6 on edge square to the roof pitch if possible. The flat 2x4 is ineffective for most of the distance between braces.

[jlybolt]

homebild, thanks. Interesting point of view but it doesnt really say that you cant splice it. Its similar to the code saying that the roof decking should be solidly decked. I am not saying your wrong and it definetely is a poor framing job. Like I said earlier an engineer may be required not only due to the splice but the actual purlin being installed incorrectly (if indeed its a purlin, which it does appear to be) and providing inadequate support. If it was my call I would be calling out for further evaluation.

[Richard A. Hetzel]

A "purlin" is a secondary member that spans between primary roof framing members such as trusses. A purlin is not a support for trusses or rafters. Such a support is called a "beam" or a "girder". The 2x4 in the picture has a lot of growing to do before it can assume either of those names. A 2x6 would barely be any better. Since there is a rafter splice, the rafters are structurally compromised, and must be properly supported under the splice by a beam or girder which is designed to carry the loads of the roof to points in the structure below, where such loads have a direct path to the earth. I'd expect to see something like a pretty beefy double LVL where that 2x4 is, but without knowing the exact roof load nor the span of the girder, that's all that can be said. The roof framing is improper, and requires evaluation by an architect or structural engineer.