Ridge board required

[Michael Thomas]

- My notes say:

R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter.

However, I occasionally see diagrams such at the one below.

Is there a exception for "directly opposed" rafters, or not?








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[Jerry Peck]

(red text is mine)

- My notes say:

R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter.

However, I occasionally see diagrams such at the one below.

Is there a exception for "directly opposed" rafters, or not?

You've already got that covered, except for the part about the gusset plate, which they missed.

From the 2006 IRC. (underlining and bold are mine)
- R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.

[Michael Thomas]

So where does (did?) the exception cited in that diagram for "directly opposed" rafters come from?

[Jim Luttrall]

- My notes say:

R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter.

However, I occasionally see diagrams such at the one below.

Is there a exception for "directly opposed" rafters, or not?

That is the OR in your post of the code. As in, rafters framed to ridge board OR to each other. You can't frame to the other rafter if there is not an opposing rafter there to frame to. Thus, a rafter must be framed to a ridge board or an opposing rafter.

[Jerry Peck]

You can't frame to the other rafter if there is not an opposing rafter there to frame to. Thus, a rafter must be framed to a ridge board or an opposing rafter.

And you can't put a gusset plate on two non-opposing rafters either, not without bending the gusset plate at all kinds of angles. The gusset plate can, however, be placed on the sides of two opposing rafters.

[Wayne Carlisle]

Here's a picture from the 2006 IRC Commentary

[Michael Thomas]

I agree that the code calls for a ridge board or gussets, but that's not what the diagram shows, and I've seen a number of such diagrams...



so I'm wondering, just for my own edification, if there was some sort of exception for opposing rafters at one time.

[Jerry Peck]

so I'm wondering, just for my own edification, if there was some sort of exception for opposing rafters at one time.

You mean "and without gusset plates", I presume?

[Scott Patterson]

I agree that the code calls for a ridge board or gussets, but that's not what the diagram shows, and I've seen a number of such diagrams...



so I'm wondering, just for my own edification, if there was some sort of exception for opposing rafters at one time.

Who did the diagram come from? I have never seen opposing rafters without a gusset plate or ridge board. I would say that the diagram is wrong.

[Wayne Carlisle]

Well the 1979 UBC states: Rafters shall be framed directly opposite each other at the ridge. There shall be a ridge board at least 1-inch nominal thickness at all ridges and not less in depth than the cut end of the rafter.

The 1988, 1991, 1994, 1997 UBC states the same thing.

2000 is the year the IRC came out and that is when that part of the code was chaged to allow gussetts instead of a ridge.

The drawing is not a code compliant drawing.

[Jerry Peck]

From the old Standard Building Code (1991, 1994, 1997)
- B2309.1.2 Where rafters meet to form a ridge, they shall be placed directly opposite each other and nailed to a ridge board not less than 1 inch (25.4 mm) thick, and not less in depth than the cut end of rafters.

As Wayne said, all framed to opposing each other with a ridge board, then the 2000 IRC and the change to allowing gussets instead of a ridge board (but rafters still are to be framed opposing to each other).

From the 2000 and 2003 IRC.
- R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25.4 mm) nominal thickness and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.

Being as the ICC codes are from a committee of the model codes, the only way that would have gotten in there as an alternative would have been if one of the model code participants had that in their code.

As the Uniform Building Code and the Standard Building Code did not have that, then the other code, the BOCA Code, must have had that in there.

[Michael Thomas]

Wayne and Jeryry,

Thanks for the research.... I guess it's just "wrong without any reason".

------------

Scott,

Don't remember where I got it originally, but I've seem others like it as well, (and of course many roofs without ridge boards). The first place GOOGLE finds it is in the (cough, cough ) "Expert Answer" here:

MMH: Product, Material & Finishes, Rooms, Outdoors, Systems, Structure & Exterior, Moving

[Richard Stanley]

I have seen quite few older homes framed with 2 x 4 rafters opposing each other with no ridge board. If they have been there that long with no problem, it is above my pay grade to complain about it. Most of these (all) were built prior to the 50s. I guess thats the way they did it when they had real carpenters.

[Jerry Peck]

it is above my pay grade to complain about it.

I have never felt it "was above my pay grade to complain about" something which did not look right, after all, I reasoned, that was what *I WAS PAID TO DO*, making it within my pay grade.

Just because something as "passed the test of time" does not mean it has "passed" the "test of time", all it may mean is that "not enough time has passed" to show its failures and deficiencies.

Take those structures down there which have survived several hurricanes, that DOES NOT mean they will survive the next one.

[archivoyeur]

"Gusset plates omitted for clarity"

[Jerry Peck]

"Gusset plates omitted for clarity"

Is that on there and I and other keep missing it, or is that something you know "should be on there"?

I don't even see it in the explanation above those drawings.

[archivoyeur]

Is that on there and I and other keep missing it, or is that something you know "should be on there"?

I don't even see it in the explanation above those drawings.

"Notation removed for obscurity"