Because inspectors know:whistling:whistling

 

Passed a framing inspection today with birds mouth cuts. The birds mouth does not effect the strength of the rafter if done properly.

 

One of my favorite sayings I use when discussing code issues with others:
Like many things in life - the Code is quite simply Black and White…
with a whole lot of Gray in-between

I will give you my thoughts,
You might have your own thoughts,
But in the end… the AHJ has the last word

 

Ask the inspector to cite where in the code it prohibits birdsmouths.

If the inspector is incorrect, and in this case I believe he/she is, in the end the code has the final word.

Looking at the CRC (California Residential Code) which is the IRC with some minor changes as California can't stand to have anything stand on its own I found this that I think will apply.

R802.7 Cutting and notching. Structural roof members shall
not be cut, bored or notched in excess of the limitations specified
in this section.
R802.7.1 Sawn lumber. Notches in solid lumber joists, rafters,
blocking and beams shall not exceed one-sixth of the
depth of the member, shall not be longer than one-third of
the depth of the member and shall not be located in the middle
one-third of the span. Notches at the ends of the member
shall not exceed one-fourth the depth of the member. The
tension side of members 4 inches (102 mm) or greater in
nominal thickness shall not be notched except at the ends of
the members. The diameter of the holes bored or cut into
members shall not exceed one-third the depth of the member.
Holes shall not be closer than 2 inches (51 mm) to the
top or bottom of the member, or to any other hole located in
the member. Where the member is also notched, the hole
shall not be closer than 2 inches (51 mm) to the notch.
Exception: Notches on cantilevered portions of rafters
are permitted provided the dimension of the remaining
portion of the rafter is not less than 4-inch nominal (102
mm) and the length of the cantilever does not exceed 24
inches (610 mm).
R802.7.2 Engineered wood products. Cuts, notches and
holes bored in trusses, structural composite lumber, structural
glue-laminated members or I-joists are prohibited
except where permitted by the manufacturer's recommendations
or where the effects of such alterations are specifically
considered in the design of the member by a registered
design professional.

 

Prolly due to trusses--don't have to know anything with them but 22.5/25.5 and played with leggos as a kid.

 

Properly cutting a birds mouth is important. I once saw a framer overcut them with a circular saw so he didn't have to use a handsaw to finish the cut. They were also cut so the level point on the rafter was a couple of inches inside of the top plate.

He was cutting them that way to match the heel height of adjacent trusses. And of course the inspector was the jerk when he did his job and failed the framing inspection.

 

I've hand cut hundreds of roofs and have NEVER finished a birdsmouth cut with a handsaw. I've also done the exact same thing with the seat cuts to match bastard roof HAPs. Never had an issue with an inspector and in 30+ years, have never seen a structural issue as a result of doing so.

 

Cut your stair stringers that way also? Most carpenters I know would consider that kind of work substandard. But then I don't spend much time in an environment where production trumps craftsmanship.

 

Actually, I don't, but now we're talking two different animals. Show me where overcutting a birdsmouth by the 3/4 to an inch it takes to clear the bottom of the cut affects the structural integrity of the rafter. The 6-7 inches left in the heel is more than sufficient to support the 12-16" overhangs typical here. As for the seat cut, if the rafter is tied into a ceiling joist, I'm hard pressed to see an issue with it sitting a couple inches in from the plates edge. By the time the rafter shrinks and stabilizes, the full cut doesn't sit on the plate anyway. If its cathedral, a ledger is ripped to match the slope and is installed to a chalk line snapped on the double plate. Feel free to visit my profile and look through a few of my pics if you doubt my credibility.

 

How is over cutting a birds mouth enough to remove it hurt anything unless you have 10' tails

 

Figured I'd throw out a few bones and show a few pics of my production built, lack of pride and craftsmanship hackery.:sad:

 

I don't know how you live with yourself:no:

 

Yeah, but are any of them still standing?:thumbsup:

 

:whistling

Every one I've built since I've been in business. The majority of which saw the eye of Sandy pass directly overhead.

Guess I didn't hack 'em up too badly.:clap:

 

Cut your stair stringers that way also? Most carpenters I know would consider that kind of work substandard. But then I don't spend much time in an environment where production trumps craftsmanship.

Shiz- ill admit to over cutting my stair stringers. Almost all the stairs I build are 4' or under on width and in a place where the sides are nailed to a wall. Only the 2 midspan stringers are fully bearing. I don't how the 1"1/4 lsl AND the 3/4 osb I use for riser material AND the 1"1/8 stair tread I put on are in any way inferior just because I over bit the stringer. I could spend the extra time to hand saw but why waste time on something that makes no difference and that no one will see.

 

I don't overcut mine because 95% or better are exterior stairs built from pressure treated lumber and are almost always visible from the underside. Other than appearance and trying to avoid a moisture/dirt trap, I see no harm in overcutting stairs either.

 

Figured I'd throw out a few bones and show a few pics of my production built, lack of pride and craftsmanship hackery.:sad:

Do you always run a key/ king common and then cut the hips short like in your pic, or just when usin double hips?

 

I always pin the ridges with a common on the end. It locates all my intersecting points. This allows the hips to set themselves. If the measurements are right, the tops only fit in one place, where the corners of the hips plane out on both edges. The location on the plate sets itself by default, provided the building is square.:whistling

 

I don't overcut mine because 95% or better are exterior stairs built from pressure treated lumber and are almost always visible from the underside. Other than appearance and trying to avoid a moisture/dirt trap, I see no harm in overcutting stairs either.

I'd do the same on something seen. Just goes to show you can't make blanket statements like "over cutting is bein a hack". We all encounter different situations where different methods are used.

 

True, just as I stated that I never finished a BM with a handsaw. In retrospect, I've had some bastard hips and valleys that were very exaggerated and did use either a handsaw or reciprocating saw to finish the cut.:whistling

 

Ive been running my hips to the ridge and then cutting the key short. There's not much of a way to nail the ridge to key till you get the hips up. Just the way I've been doin it, maybe I'll try yur way next time

 

Ive been running my hips the the ridge and then cutting the key short. There's not much of a way to nail the ridge to key till you get the hips up. Just the way I've been doin it, maybe I'll try yur way next time

If you look closely at the first and second pics I posted, there is a steel plate sandwiched between LVL ridges. If I recall, it's around 38' long and has a pitch on either end of it. Scary getting that set and pinned in place, especially since one end bears on a CMU wall that didn't exist when the beam was set.:laughing:

 

If left up to me that's what I do- 12" gable oh's (barges) and 16" facia oh at eaves.

 

we cut rafters all the time on the additions we do. and all of them get birdsmouths. the inspectors dont say a thing about it. if they do comment its just on how tight the cuts are

 

He probably thought about how it's not allowed in i joists and i joists are so much better than dimension lumber

 

They actually are allowed in I-joists, provided you follow manufacturers guidelines.

 

I've hand cut hundreds of roofs and have NEVER finished a birdsmouth cut with a handsaw. I've also done the exact same thing with the seat cuts to match bastard roof HAPs. Never had an issue with an inspector and in 30+ years, have never seen a structural issue as a result of doing so.

I agree totally! It's not a stair stringer. They only possible problem you could have by over cutting a birds mouth is making the overhang weaker. But you would have to really overcut. All it does is set up your overhang and give you a "stop" so your rafters are all set in the same distance from the ridge and you can maintain a consistent overhang. Any framer has built parts of a roof where there is no birds mouth. They all get hurricane ties anyway.

 

As this Q & A from the current issue of JLC shows,not only are birds mouths allowed,how do you get by without them?



http://www.jlconline.com/framing/q-birdsmouths-in-rafters-are-they-necessary.aspx

 

Ive framed 1000's of roofs no lie. Still stick frame them in the south in high wind zones. Cant stand trusses. The rep is wrong that isnt non typical any more.
With reg to the dep. of cut rule of thumb as long as you have enough meat to = a 2x4 truss top cord then what is the issue?
In florida they are on the way stucco lathe is installed we stated doing plaster back in the 40's so I have some clue what I'm doing. Any way they want it only one direction or the openings of the grid if you get my drift. Any way I chalange the inspector because I know my state codes he wouldnt back down so I asked this next question. What direction should I place it on a ceiling or arched openings crickets.

 

Back to OP, how could you get by without one? What's the rafter to bear on, a single point of edge contact? THAT should fail an inspection.

 

The OP made and only has 1 post and has since disappeared so I doubt we have the whole story. It simply does not sound right at all. There are millions of stick built roofs in the US with tens of millions of birds mouths that are working just fine. Just don't over notch if you are going to have a lot off rafter tail and all should be fine.

 

JLC has an article on this subject this month. The alternatives are a pain. Fastener schedules, engineered bracket specs...not to mention the the structural hurdles. Birdsmouths are the best way to tie in and ensure structural integrity.

 

Why wouldn't you cut a birds mouth?

 

I carry a code book in my truck. When ever I have an inspector say that is not allowed or it is against code and I know I am right I hand him the book and ask him to show me. Most of the time I am proven right and he has to pass me. Now that sets the tone for the rest of the project. For that reason I pick and choose my battles carefully. After all he has the final say.

 

I was told the burden of disproof is on my shoulders.

 

This is how it works:

1) The inspector should give you the code section if you ask for it.
2) If you don't agree, discuss it like professionals.
3) If you still don't agree you have the right to an appeal
4) If the appeals board does not agree with the inspector then you were right.

We rarely get appeals but never lost one because we never let it get that far without trying to hash it out civil like.

We all make mistakes and we should learn from them. I have said it before and will say it again. If I am wrong, prove me wrong and I will be happy to back down and admit you were right and I was wrong. If you challenge the code official in a professional manner, someone will learn something so it is a positive thing. Code officials should never hold a grudge.