Thread: staggered rafters

Ever see rafters that are staggered where they are nailed to the ridge board instead of inline with each other?

What would some of the problems be as a result of this?

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If it is a structural ridge, I believe that is acceptable.

If that is a regular ridge board, the rafters are required to be opposite and aligned with each other. This is to transfer loads from rafter-to-ridge-to-rafter.

Its the ridge board running down the center in the peak of the attic.
The one where all of the rafters at the top peak attach to the ridge board.

Just to clarify, when you say structural, which one are you talking about?

Thanks.

The alignment is not far off center. I would not take issue with it.

Wes,

A ridge board is supported by the rafters against it.

A structural ridge is supported by posts, walls, etc. below it. With a structural ridge, the rafters *are being supported by* the ridge, not *supporting the ridge*.

Gotcha.

So, this would be a regular ridge.

What would you recommend in the report?

I don't see enough conventional framing to really know, not having checked into it before.

I've always seen trusses (since I started building and then inspecting).

Do you see any nail heads in those rafters? NO. Thats because they were staggered to allow face nailing through the ridge the same as you would do with fire stop or bridgeing. While there appears toi be no structural issue no experienced framer would put his name on that one.
Call it as it is. Framing appears unprofessionally installed. REcommend obtaining paperwork on framing inspections performed by local code enforement to insure all was passed. And in fine printLOOKS LIKE ****

Originally Posted by wayne soper

Do you see any nail heads in those rafters? NO. Thats because they were staggered to allow face nailing through the ridge the same as you would do with fire stop or bridgeing.

That's a good point.

Face nailing through the ridge means end nailing into the rafters.

Everyone knows that end nailing is of limited (very limited) value.

In todays world with manufactured roof rafters you soon become lulled into this world of trusses. In the old days when a ridge beam was set and the roof raters were nailed to the ridge beem ti set the nails through the ridge beam then some time there woud be a slight off set. The off set is ok how else could you nail through the ridge beam. Yes in a perfet work they would be aligned but the purpose of the rige bean is to transfer the pressures between the two rafters. So some off set would be acceptable.

section 2320.12.3 framing. rafters SHALL be framed directly opposite each other at the ridge....etc. i would call it a defect! this quote from the 2001 calif bldg code(1997 u.b.c.)

I have seen many many houses framed this way. Are you guys suggesting that toe nailed rafters have more strength than face nailed? (brackets aside) The 2003 IRC says the rafters should be framed to the ridge, but there is no language that I could see on quick glance that said, exactly opposite each other. You would have a busy writing hand if you choose to write it up here in the south. Just my two cents.

martin,
section 2308.10.4 of the 2003 ibc has the exact same wording!free up your hands for some serious writing

They're only offset the thickness of the ceiling joists, making it easier for nailing at both the top and bottom of the rafter. Not as clean as directly opposing, but no problem. (I'm 30 yrs. a carpenter, CA and CO).

kenton,
i'm 30 years carpenter and 15 years inspector! i enforce written code!problem!

Brian SC is using the 2003 IRC One and Two Family Dwellings, and...R802.3 Framing details says.."Rafters shall be framed to a ridge board, or each other with the use of gusset plates?" etc... But honestly, this type of construction is rarely seen today, as most home are trussed. I still don't see how you consider toe nailed construction stronger than face nailed. (Hanging plates aside) I also believe that rafters on opposing sides of the same line, are not in any danger of causing a failure of the 2x ridge board. As a matter of fact I've seen 150 year old homes framed to a 1x6 ridge with staggered rafter nailing that are still there today. Moreover, they look better than the 2x4 trusses on 24" center, with sagging sheathing between, that I see all the time. Remember there is no snow load here.
Martin

I treat 2" nominal offset the same as in-line, more than that I call it as poor workmanship. Seems like this is the tolerance with lining up rafters to studs without a doubled top plate. This allows face nailing, but keeps the ridge from being pushed back and forth. If it is a planned layout and tight workmanship with no apparent movement, I am happy. So much framing is done by low/no skilled laborers, it is just a pleasure to see something where thought and pride is put into a job. JMO

Originally Posted by brian schmitt

kenton,
i'm 30 years carpenter and 15 years inspector! i enforce written code!problem!

Ah Brian, Brian, mixing code inspection and home inspection, I believe your good judgement has gone South as you enter your golden years. I'm only a sprightly 55.
Seriously though, I'm curious, I can understand your pointing it out as not complying with code, which is generally designed to keep people safe, but what's the problem with this condition, do you really see it failing or causing problems at some point, and what would your recommendation be?

CODE is such a four letter word. If we were code cops, i would quote code. But alas we are not. The staggered ridge is a highly accepted practice in the midwest. The ability to face nail the ridge to the rafter is a much stronger connection than toenailing or angle nailing when the rafters are perfectly aligned. The fact that the rafters are not directly across from each other has no bearing on the pressure transfer as long as it is no more than the thickness of the ridge (each side of the center line). Just because code says one thing does not mean there are not any other accepted best or better practices out there. Code is a license to steal and it is not GOD.

Originally Posted by Steve Duchene

The staggered ridge is a highly accepted practice in the midwest.

It is also standard practice in most areas to drive well over the legal speed limit ... but that does NOT make it "right".

The ability to face nail the ridge to the rafter is a much stronger connection than toenailing or angle nailing when the rafters are perfectly aligned.

Quite to the contrary. Nailing into the end grain gives about the weakest connection possible.

Code is a license to steal and it is not GOD.

No, CODE is only "the crappiest one is legally allowed to construct something".

CODE is not something 'to strive for', CODE is 'where you start' - you HAVE TO at least meet CODE minimum.

Quite to the contrary. Nailing into the end grain gives about the weakest connection possible.

Jerry,
I have to disagree with this statement. The end grain you speak of is the same end grain through which the toe nail is driven. Furthermore, in nomal directly opposed installation, one of the two rafters is face nailed and one is toe nailed. Coated nails (and collar ties) make face nailed rafters very strong and having had to pull more than a few loose, I can tell you they hold better than toe nailed. How can a nail that is partially through the end grain hold better than one that is fully in the end grain anyway?
Martin

Actually, face nailing the rafters like this gives you just about the strongest connection possible without metal straps. End grain nails are weak in pullout resistance, but very strong in shear loads. The collar ties handle the pullout, so the end nails only handle the roof weight in shear.

Also, what is the definition of directly opposite? Plus or minus the width of the board (usually 1.5") is usually considered within tolerance.

kenton,
when i frame roofs i use a 1x riddge and nail one rafter straight on and angle the nails on the second rafter thru the ridge and into the opposing rafter. i alternate this pattern as i fill in the rafters. my father and two brothers were general contractors and i was taught to make rafters oppose each other.it is good craftsmanship and code which i now am mandated to enforce. my personal opinion is that it is a hack job that should be corrected.

Originally Posted by brian schmitt

kenton,
when i frame roofs i use a 1x riddge and nail one rafter straight on and angle the nails on the second rafter thru the ridge and into the opposing rafter. i alternate this pattern as i fill in the rafters. my father and two brothers were general contractors and i was taught to make rafters oppose each other.it is good craftsmanship and code which i now am mandated to enforce. my personal opinion is that it is a hack job that should be corrected.

From a carpenter's perspective we're in agreement there Brian. From an inspector's viewpoint we're different, but that doesn't really matter. Inspection requirements vary by state and we each need to feel comfortable with our recommendations.

Face nailing beats toe nailing without question, that is if the face nailing is reasonable centered into the connecting member. Our old UBC did allow rafter offset at the ridge, but no more than the thickness of the rafter.
What's tough is making a call on something structural that's been that way for 40 - 50 years without any visual signs of stress or failure. In particular are floor joist support girders that are usually over-notched at the cripple walls. "The old framer" who is happy he has retired.

jerry,
when i learned to frame in the oakland hills i was under the 1961 u.b.c.. section" 2515(b)roof construction......rafters SHALL be framed directly opposite each other at the ridge and shall be nailed to adjacent ceiling joist to form a continuous tie between exterior walls."so much for the 40 year always dun it that way arguement. wrong then ,wrong now!

Wes,

Honestly that is some of the worst rafter framing I have seen yet!

The underlayment for the roof doesn't even meet the Ridge board....
What other than a couple of 16 penny are Holding it into place?

You can't build a proper load bearing structure if both sides of the home don't meet to bear the stress

there will be immense shifting, and stress on the vertical supports

What type of roof is there? Please tell me it's NOT tile of any sort....

WOW what we see!
~Wen~

Single layer composition shingles.

Originally Posted by Wen Myrick

The underlayment for the roof doesn't even meet the Ridge board....

Not sure if you're joking, or if you have no ridge vents in your neck of the woods...

Originally Posted by Martin Baker

Quite to the contrary. Nailing into the end grain gives about the weakest connection possible.

Jerry,
I have to disagree with this statement. The end grain you speak of is the same end grain through which the toe nail is driven.

Not quite correct, but, for the sake of discussion, it is the "same grain" in that it is the "same section of the wood", however, when toe nailing, the nail is being driven "through" that grain, not "into" that grain.

Try this: Take your pocket knife and try to jab it "through" that grain through the face of the 2x. Then take you pocket knife and try to jab it "into" that grain through the end of the 2x.

You are incorrect about referring to that as "the same grain" because "end grain" means the grain of the wood at the cut off end, once you are looking at it from any other angle, it is no longer "end grain".

You will find that jabbing/nailing/etc. "into" the "end grain" is a lot easier than jabbing/nailing/etc. "through" the side of the 2x.

[quote[How can a nail that is partially through the end grain hold better than one that is fully in the end grain anyway?
Martin[/quote]

Because, when the grain of wood is nailed through sideways (not into the end grain) the wood fibers are forced apart under tension. Think of the wood fibers (the grain) as being long strings held taunt in place. You are pushing them apart against their being held in place.

When nailing into the end grain, you are simply driving a wedge between the wood fibers, with nothing to create the tension needed to hold them tightly together. You are actually splitting them apart, starting at their ends.

I believe their is an allowance of up to 1 board width of offset.

John,

No Ridge vents here! Just soffit vents.
Except on the metal roofs that look like Shake.

See why it's important for Brian to leave this site as is.......I just learned something from another state....
Are you sure it wasn't a miscalculation of materials?

~Wen~

Oh........AND Gable vents..........AND Attic vents (turbines and tapered)

(forgot to mention)
~Wen~

Originally Posted by Jerry McCarthy

Face nailing beats toe nailing without question, that is if the face nailing is reasonable centered into the connecting member. Our old UBC did allow rafter offset at the ridge, but no more than the thickness of the rafter.
What's tough is making a call on something structural that's been that way for 40 - 50 years without any visual signs of stress or failure. In particular are floor joist support girders that are usually over-notched at the cripple walls. "The old framer" who is happy he has retired.

The alignment of the rafter pairing allows for proper collar ties and being offset by one rafter width is putting undue strain on them.
Let it be said that age will tell if it is too far from the ridge and opposing rafter.
T.Neyedli
www.alphahomeinspections.ca