Ceiling framing

[jar546]

Anyone finding any issues with this?

Limited viewing, comment on what you can see. This is a drill........

 

[TJacobs]

Is the scaffolding staying??? LOL

 

[jar546]

And as an FYI, those rafters go to a ridge board, not a ridge beam

 

[mtlogcabin]

Add some purlins would it then be "Braced Rafter Construction"? It has to be putting a load on that wall.

 

[Code Neophyte]

Does it say anywhere in the rafter tie provision of the IRC that the rafter ties have to be parallel to the floor? One end connected at the plate (of a center partition) and one in the center third of the rafter span?

 

[Yankee]

I have never found that "bottom third" that has been referenced several times for rafter ties. There is a chart to use if the tie is above the plate. Where does the "bottom third" come from?

I would say that as a rafter tie, this doesn't cut it. Generally this type of set-up would accept some of the roof loads (rafter bending), but not in the anti-spreading direction.

 

[TimNY]

In addition, the gable end may need bracing, methinks.

 

[Mule]

You know...I really don't see a problem with this but I can see where you could say that since there are no rafter ties that a beam would be required where the rafters meet to keep the wall from spreading. Maybe I haven't really read that deep into the code....

Yankee... we get the bottom ...actually 2/3 as being rafter ties beacuse of the definition of collar ties are in the upper third of the attic space.

Collar ties or ridge straps to resist wind uplift shall be

connected in the upper third of the attic space in accordance

with Table R602.3(1).

 

[Rio]

It looks like those are rafter braces which brings up the question of how well supported from lateral movement is the wall they are bracing to. It looks like the bracing might be at a larger than 45 degree angle. I would see how far the rafters are spanning to see if the braces weren't there if the rafters will be overspanned.

Looking at it again it appears that they are planning on making this area into a smaller room inside the larger area. If that's the case a whole other can of worms is opened. As pointed out there's a hinge at the gable end framing and rafter tie issues and questions.

 

[Yankee]

You know...I really don't see a problem with this but I can see where you could say that since there are no rafter ties that a beam would be required where the rafters meet to keep the wall from spreading. Maybe I haven't really read that deep into the code....Yankee... we get the bottom ...actually 2/3 as being rafter ties beacuse of the definition of collar ties are in the upper third of the attic space.

Collar ties or ridge straps to resist wind uplift shall be

connected in the upper third of the attic space in accordance

with Table R602.3(1).

Right, but I often hear someone say or see a post that says "the rafter tie can be in the bottom third (now you are saying 2/3rds) of the attic space and I see nowhere in the prescriptive code that allows such. The placement of the rafter tie, if anywhere but on the plate, is determined by the tables in the IRC. Just putting them anywhere in the bottom third without running the numbers and adjusting the required connection does not meet code.

I'm I misunderstanding this section?

 

[mueller]

Yankee I have never found that "bottom third" that has been referenced several times for rafter ties. There is a chart to use if the tie is above the plate. Where does the "bottom third" come from?I would say that as a rafter tie, this doesn't cut it. Generally this type of set-up would accept some of the roof loads (rafter bending), but not in the anti-spreading direction.

The only place I ever found that bottom 1/3 is in footnote A of the rafter span tables.

If the

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters

on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be

multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor

1/3 0.67

1/4 0.76

1/5 0.83

1/6 0.90

1/7.5 or less 1.00

where:

HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR = Height of roof ridge measured vertically above the top of the rafter support walls.

If the rafter tie is any higher than 1/3 I don't see any prescriptive way to adjust the rafter span.

 

[Mac]

The 'birds mouth' cuts at the ceiling joist tails (left side) look pretty deep. I'd call them 'notches not in compliance with R802.7.1' because they are more than one sixth of the depth (is it a rafter or a ceiling joist?). Those cuts in those locations are prone to starting a split that can run upwards and cause problems. Hard to see, but I think a split can already be seen starting at the second one in from hte end wall.

 

[fatboy]

In addition to the replies so far, I have a problem with the method of attachment at the new "ridge". There is not anything that really represents an opposing rafter, other than the short horizontal member and the shear of the nails.

 

[Mule]

In addition to the replies so far, I have a problem with the method of attachment at the new "ridge". There is not anything that really represents an opposing rafter, other than the short horizontal member and the shear of the nails.

Fatboy, the opposing (opposite) rafter is no longer in the code........

 

[fatboy]

"R802.3 Framing details. Rafters shall be framed to ridge board

or to each other with a gusset plate as a tie."

There is neither.

 

[Yankee]

"R802.3 Framing details. Rafters shall be framed to ridge boardor to each other with a gusset plate as a tie."

There is neither.

Those aren't rafters, they are somthing to attach the finished ceiling to. I don't believe they are intended to be assiociated with any roof loading at all. The apparent lack of rafter ties is a seperate issue.

 

[fatboy]

OK, fine, they don't comply with R803.1. My point was the connection, not the nomenclature, sorry I wasn't specific.

 

[Mule]

Can the connection of the two rafters/ceiling not satisfy the intent of a gusset plate?

What is a gusset plate?

Isn't it an apparatus to connect two pieces of material together? Would the rafter/ceiling/joist lapping by the rafter contitute a gusset?

 

[Yankee]

A gusset is a triangular or square piece of fabric inserted into a seam to add breadth or reduce stress from tight-fitting clothing. Gussets were used at the shoulders, underarms, and hems of traditional shirts and chemises made of rectangular lengths of linen to shape the garments to the body.[1][2]

Gussets are used in manufacturing of modern tights or pantyhose to add breadth at the crotch seam; these gussets are often made of breathable fabrics for hygiene when wearing pantyhose without panties.

The term "don't bust a gusset" comes from this sewing term; a gusset in this context was usually a piece of fabric sewn between two others to increase mobility or increase the size of the pant waist, the latter being more common in the early 1900s.

Gusset is also an alternate spelling of gousset, a component of late Medieval armor which functions similarly.

 

[Mule]

Okay...so there you have it..install a pair of panty hose on it and it complies!

 

[Mule]

Seriously now.... in my opinion I would rather see two 2X6's lapped by that way and nailed together than seeing one of them cut to fit underneath with a piece of plywood nailed over the joint with roofing nails.

 

[fatboy]

I believe the intent of the section is that the rafters would be opposed to each other, with a gusset plate acting as the tie to keep them opposed, and self-supporting. However, this section has been so watered down it doesn't say that anymore. I, once again, sure miss the 97 UBC..........sigh.

 

[Mule]

fatboy....me too! About the time I learned where everything was in the UBC they done went and screwed everthing up by merging everything together.................dang hillbilly looking fools!!!!

 

[TJacobs]

I'd call them ceiling joists, but they still don't tie the outside walls together.

Those aren't rafters, they are somthing to attach the finished ceiling to. I don't believe they are intended to be assiociated with any roof loading at all. The apparent lack of rafter ties is a seperate issue.