Ridge beam per 2006IRC vs. 2003IRC

[rktect 1]

Section 802.3.1

I am trying to find out what this section said in the 2003 IRC.

Basically I wrote a review for a cathedral space that the ridge board for the roof is now required to become a ridge beam and that both ends of that ridge beam are required to be supported.

What was required previously? The DP said he never heard of this and that he is showing collar ties spaced at 32" o.c in the upper third of the attic and hurricane clips at the top plates to resist the gravity forces.

 

[Mule]

Re: Ridge beam per 2006IRC vs. 2003IRC

The hurricane clips at the top plates do nothing to keep the structure from spreading outward. That's why you need the ridge beam to keep the walls from spreading.

By the way....here are the codes on-line to view for free!

http://publicecodes.citation.com/icod/index.htm

Here is the section of the 2003 IRC.

BOLD is mine

R802.3.1 Ceiling joist and rafter connections.

Ceiling joists and rafters shall be nailed to each other in accordance with Tables R602.3(1) and R802.5.1(9), and the assembly shall be nailed to the top wall plate in accordance with Table R602.3(1). Ceiling joists shall be continuous or securely joined where they meet over interior partitions and nailed to adjacent rafters to provide a continuous tie across the building when such joists are parallel to the rafters.

Where ceiling joists are not parallel to rafters, subflooring or metal straps attached to the ends of the rafters shall be installed in a manner to provide a continuous tie across the building, or rafters shall be tied to 1-inch by 4-inch (25.4 mm by 102 mm) (nominal) minimum-size cross ties. The connections shall be in accordance with Table R602.3(1) or connections of equivalent capacities shall be provided. Where ceiling joists or rafter ties are not provided at the top plate, the ridge formed by these rafters shall also be supported by a girder designed in accordance with accepted engineering practice.

Rafter ties shall be spaced not more than 4 feet (1219 mm) on center.

 

[steveray]

Re: Ridge beam per 2006IRC vs. 2003IRC

All taken from 2003 IRC, hope it helps! I think there is more, but I may be confusing it with my CT amendments!

R802.3.1 Ceiling joist and rafter connections.

Ceiling joists and rafters shall be nailed to each other in accordance with Tables R602.3(1) and R802.5.1(9), and the assembly shall be nailed to the top wall plate in accordance with Table R602.3(1). Ceiling joists shall be continuous or securely joined where they meet over interior partitions and nailed to adjacent rafters to provide a continuous tie across the building when such joists are parallel to the rafters.

Where ceiling joists are not parallel to rafters, subflooring or metal straps attached to the ends of the rafters shall be installed in a manner to provide a continuous tie across the building, or rafters shall be tied to 1-inch by 4-inch (25.4 mm by 102 mm) (nominal) minimum-size cross ties. The connections shall be in accordance with Table R602.3(1) or connections of equivalent capacities shall be provided. Where ceiling joists or rafter ties are not provided at the top plate, the ridge formed by these rafters shall also be supported by a girder designed in accordance with accepted engineering practice.

Rafter ties shall be spaced not more than 4 feet (1219 mm) on center.

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.

R502.6 Bearing.

The ends of each joist, beam or girder shall have not less than 1.5 inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete except where supported on a 1-inch-by-4-inch (25.4 mm by 102 mm) ribbon strip and nailed to the adjacent stud or by the use of approved joist hangers.

 

[rktect 1]

Re: Ridge beam per 2006IRC vs. 2003IRC

Mule,

If the BOLD portion is something that you wrote, then did it not exist in the 2003 IRC?

I looked it up in the 1995 CABO and it is definatly in there. 802.2.1CABO Cathedral Ceilings.

 

[TJacobs]

Re: Ridge beam per 2006IRC vs. 2003IRC

You need the "hurricane clips" at the rafter-to-top plate connection because you won't have the additional nailing that the ceiling joist nailed to the rafter and nailed to the top plate gives you.

 

[brudgers]

Re: Ridge beam per 2006IRC vs. 2003IRC

There's nothing magic about hurricane clips.

Additional toe nailing may work.

Either way, you have to run the calcs.

 

[cboboggs]

Re: Ridge beam per 2006IRC vs. 2003IRC

RK, the section Mule quoted is correct. It is in the book at the end of the second paragraph of Section R802.3.1.

 

[rktect 1]

Re: Ridge beam per 2006IRC vs. 2003IRC

Ok, so this has been standard for some time then. I really asked because I don't have the previous codes from IRC and the 802.3.1 section located in the 2006IRC shows that great big black line running vertically on the side which says they (ICC) had modified the entire section so......I was really starting to wonder as the DP says he had been doing cathedral ceilings like this for 30 years. :shock:

 

[Mule]

Re: Ridge beam per 2006IRC vs. 2003IRC

rktect, I was just bolding to show the point about what you asked. Sorry for the confusion.

The reason for the dark line in the 2003 is because of the difference to what I bolded from the 2003 and the 2006 IRC. They are a little more specific in the 2006.

 

[GHRoberts]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

 

[rktect 1]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

How much?

Enough or not enough?

The ones being provided were on the inside.

 

[GHRoberts]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

How much?

Enough or not enough?

The ones being provided were on the inside.

Ask the design professional for the calculations. When he gives them to you, thank him and approve the structure.

 

[kilitact]

Re: Ridge beam per 2006IRC vs. 2003IRC

GH Roberts wrote;

Ask the design professional for the calculations. When he gives them to you, thank him and approve the structure.

Review to ensure they are correct, than approve.

 

[brudgers]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

If you don't run the calculations how do you know if the hurricane clip is sufficient?

If you're not going to check the clip, you might as well accept toe nails.

 

[GHRoberts]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

If you don't run the calculations how do you know if the hurricane clip is sufficient?

If you're not going to check the clip, you might as well accept toe nails.

It is not the AHJ's job to do calculations. The AHJ may not even be licensed to do the calculations and make an engineering judgment.

 

[brudgers]

Re: Ridge beam per 2006IRC vs. 2003IRC

Either way, you have to run the calcs.

The AHJ seldom if ever should run calculations.

Certainly one can engineer rafters and ties to resist wall spreading. But the engineer should have the calculations. (And if the hurricane clips are on the outside, they will certainly provide resistance to spreading.

How much?

Enough or not enough?

The ones being provided were on the inside.

As I said there's nothing magic about hurricane clips.

Like toe nailing, they're either sufficient for the load or insufficient.

Having reviewed more than a few clipped connections, I can assure you that engineers infrequently specify them in accordance with the manufacturer's requirements.

If you have a 2009 Simpson catalog, take a look at note 6 on page 157...even really good engineers often have trouble complying with the combined load requirements.

 

[rktect 1]

Re: Ridge beam per 2006IRC vs. 2003IRC

As I said there's nothing magic about hurricane clips.

Like toe nailing, they're either sufficient for the load or insufficient.

Having reviewed more than a few clipped connections, I can assure you that engineers infrequently specify them in accordance with the manufacturer's requirements.

If you have a 2009 Simpson catalog, take a look at note 6 on page 157...even really good engineers often have trouble complying with the combined load requirements.

I have the 2009 catalog. I see the note. But I do not understand how placing the hurricane clip on the outside is going to remove the requirement for the engineered ridge beam.

 

[GHRoberts]

Re: Ridge beam per 2006IRC vs. 2003IRC

I have the 2009 catalog. I see the note. But I do not understand how placing the hurricane clip on the outside is going to remove the requirement for the engineered ridge beam.

Engineering does not require an engineered ridged beam. Engineering only requires that the loads be properly handled. One way to handle the loads is to upsize the rafters and the ties to limit the outward thrust.

 

[TJacobs]

Re: Ridge beam per 2006IRC vs. 2003IRC

As I said there's nothing magic about hurricane clips.

Like toe nailing, they're either sufficient for the load or insufficient.

Having reviewed more than a few clipped connections, I can assure you that engineers infrequently specify them in accordance with the manufacturer's requirements.

If you have a 2009 Simpson catalog, take a look at note 6 on page 157...even really good engineers often have trouble complying with the combined load requirements.

I have the 2009 catalog. I see the note. But I do not understand how placing the hurricane clip on the outside is going to remove the requirement for the engineered ridge beam.

It doesn't. It provides a better stronger rafter-to-top-plate connection to replace the additional ceiling joist nailing.

Check out these interesting web pages...I'm sure we have all seen these in our jurisdictions...

http://www.unified-eng.com/ch/thrust.html

http://www.unified-eng.com/ch/bracing.html

NOTE: I have no connection whatsoever with the above firm.

 

[brudgers]

Re: Ridge beam per 2006IRC vs. 2003IRC

As I said there's nothing magic about hurricane clips.

Like toe nailing, they're either sufficient for the load or insufficient.

Having reviewed more than a few clipped connections, I can assure you that engineers infrequently specify them in accordance with the manufacturer's requirements.

If you have a 2009 Simpson catalog, take a look at note 6 on page 157...even really good engineers often have trouble complying with the combined load requirements.

I have the 2009 catalog. I see the note. But I do not understand how placing the hurricane clip on the outside is going to remove the requirement for the engineered ridge beam.

It doesn't. It provides a better stronger rafter-to-top-plate connection to replace the additional ceiling joist nailing.

Check out these interesting web pages...I'm sure we have all seen these in our jurisdictions...

http://www.unified-eng.com/ch/thrust.html

http://www.unified-eng.com/ch/bracing.html

NOTE: I have no connection whatsoever with the above firm.

A clip doesn't necessarily provide a stronger connection than three 16d toe nails...which are good for over 300lbs of thrust/uplift/shear.

You can spec one that gives you more, but you can spec one that gives you less as well.

And it's easy to get them misinstalled when they require 10d by 1 1/2".

I've seen inspectors insist that you only get the full capacity when the nails penetrate through the member and are bent down on the back side.

 

[STB]

Re: Ridge beam per 2006IRC vs. 2003IRC

I thought the AWC stated that a toenail is rated at 50% the original bearing of a straight nail.... :?

 

[TJacobs]

Re: Ridge beam per 2006IRC vs. 2003IRC

Clinching nails gives you much greater holding power:

http://www.awc.org/pdf/wdf_nds97.pdf

http://ir.library.oregonstate.edu/jspui/bitstream/1957/2056/1/FPL_1777ocr.pdf

 

[TJacobs]

Re: Ridge beam per 2006IRC vs. 2003IRC

I thought the AWC stated that a toenail is rated at 50% the original bearing of a straight nail.... :?

Here is a good document to digest when reviewing cathedral roofs:

http://www.awc.org/pdf/ndsdesignaid.pdf

The tables have already taken the toe-nail reductions into account. 17% less for lateral and 33% less for withdrawal.

If you have ever toe-nailed a rafter, you know you need to take into account rafter splitting when using too many nails...no factor for that in the table. Plus, what are the chances that both members are the same species?

 

[brudgers]

Re: Ridge beam per 2006IRC vs. 2003IRC

I thought the AWC stated that a toenail is rated at 50% the original bearing of a straight nail.... :?

NDS [2001] Ctn = .67

It is assumed that 1/3 of the nail is in the side member.