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Correcting overnotched rafter.

GodLovesUgly

Registered User
Joined
Jul 22, 2020
Messages
6
Location
Washington
What would be suggested to correct the overnotched situation of these raters on an exterior roof structure?

Rafter is 2x10 fir resting on 6x12 Glulam beam.

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Unfortunately, the IRC does not provide prescriptive "fixes" where the code is not followed. As you should now be aware, this is a violation of IRC Section R802.7.1.1.

R802.7.1.1 Cantilevered Portions of Rafters
Notches on cantilevered portions of rafters are permitted provided the dimension of the remaining portion of the rafter is not less than 31/2 inches (89 mm) and the length of the cantilever does not exceed 24 inches (610 mm) in accordance with Figure R802.7.1.1.

0



For SI: 1 inch = 25.4 mm.


I'd suggest that you kindly ask the building inspector what he'd approve. If they do not have an answer, be prepared to hire an engineer. I'd imagine that they can work out something... possibly a sistered 2x, a joist hanger, or a structural ribbon board.
 
What would be suggested to correct the overnotched situation of these raters on an exterior roof structure?

Rafter is 2x10 fir resting on 6x12 Glulam beam.

CAhYdjx.jpg


36uIVBk.jpg


pdUkPcy.jpg



Welcome

So are you the owner or new owner or other??

Has the city already approved it or looking for a correction??
 
I am the owner and this is contracted work. It has come to my attention that the contractor did the work without proper permitting, and I will now have to pursue permits retroactively. This is a violation that stuck out as a big red flag to me.
 
If it were me, I'd propose adding a ribbon board as a fix. See the following sketch, but basically you cut a 1-1/2 bearing notch from the joist at the beam, add a ribbon board with ledger screws, and the ribbon board becomes the required 1-1/2" of bearing.

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Ty, I was thinking on the the same line, providing more meat to rest on. Simpson probably has something to attach to the beam to add support to the rafter.
 
If neatness counted your contractor gets an A. But for one split end his workmanship is good. It looks like this is intended as an open ceiling, with T&G for roof sheathing left open for aesthetics. If a ribbon or hangers aren't palatable I would see if the inspector would accept an engineered judgement. A 2x10 rafter may have been over-kill for a porch (not sure of span or snow load) and if the incised cut doesn't worry the engineer you might not need any repair. You might also need him/her to address uplift.
 
Ty, I was thinking on the the same line, providing more meat to rest on. Simpson probably has something to attach to the beam to add support to the rafter.
I was thinking a joist hanger, but it looks like there is less than 3-1/2" to use a 2x4 hanger.
 
Yes I am overall pleased with the work, they are very tight and for the most part things are overbuilt. This is one glaring issue that I can see potentially coming up. It sounds like there will be options to rectify the situation if it is flagged. Given the current COVID situation it will likeley be months before the County will even look at my application. Although not the most aestetically pleasing I would not be apposed to hangers or a ribbon board to make sure it is structurally sound. You are correct it is an open ceiling concept with T-11 sheathing facing downwards to give the T&G appearance.
 
If it were me, I'd propose adding a ribbon board as a fix. See the following sketch, but basically you cut a 1-1/2 bearing notch from the joist at the beam, add a ribbon board with ledger screws, and the ribbon board becomes the required 1-1/2" of bearing.
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Ty ... is the problem the amount of bearing for the main part of the rafter, or is it the thin section that crosses the beam and supports the overhang?
The 4” notch depth is on the inboard side, less than 1/2 the rafter depth. On the outboard side it’s a whole lot deeper. Looking at your diagram in post 3, the critical oart is the deepest dimension of the notch.
Considering the neatness of the work, i would prefer a ledger applied to the face of the beam rather than metal hangers.
 
Ty ... is the problem the amount of bearing for the main part of the rafter, or is it the thin section that crosses the beam and supports the overhang?
The 4” notch depth is on the inboard side, less than 1/2 the rafter depth. On the outboard side it’s a whole lot deeper. Looking at your diagram in post 3, the critical oart is the deepest dimension of the notch.
Considering the neatness of the work, i would prefer a ledger applied to the face of the beam rather than metal hangers.
The notch is limited to 1/4th of the depth of the rafter (see IRC Fig. 802.7.1.1 above). The limit is so that the rafter does not split along the grain. As you noted, it looks like the notch is about 50% of the interior side of the rafter. The 2x10 probably has the same strength as a 2x6 with that notch.
 
If it were me, I'd propose adding a ribbon board as a fix. See the following sketch, but basically you cut a 1-1/2 bearing notch from the joist at the beam, add a ribbon board with ledger screws, and the ribbon board becomes the required 1-1/2" of bearing.

View attachment 6797

This would have been my suggestion or hanger as others have said.
 
I doubt that it's a problem worth fixing....well except for few things. The 2"x10 is prone to twisting and the 90° corner is a spot for a re-entrant split. One of the rafters shows a slight wane that lines up perfecly for a corner split. Bearing wise it's not an issue...at least for me. The split tail would be a deal breaker...if I owned it.
 
I doubt that it's a problem worth fixing....well except for few things. The 2"x10 is prone to twisting and the 90° corner is a spot for a re-entrant split. One of the rafters shows a slight wane that lines up perfecly for a corner split. Bearing wise it's not an issue...at least for me. The split tail would be a deal breaker...if I owned it.
I am surprised by your acceptance ICE, as it is clear violation of IRC Section R802.7.1.1. As you indicated in your post, the corner of the notch is a location prone to re-entrant splitting; which, per my understanding, is partially what R802.7.1.1 seeks to address (the other aspect being dispersion of tension forces on the bottom side of the 2x member). The same "D/4 MAX" requirement can be found in IRC Section 502.8, where end cuts on floor joists are similarly limited to a notch no greater than 1/4 of the depth of the member.

With your expert level of experience, and due to my own curiosity, what makes you comfortable with this installation? If you were to reject this, what would you suggest as a corrective action?
 
Has anyone noticed that the tail is not the same dimension as the rafter? The rafter is 2x10, the tail looks like 2x4 ...
 
Has anyone noticed that the tail is not the same dimension as the rafter? The rafter is 2x10, the tail looks like 2x4 ...
Yes, it is a typical rafter tail notch. The cut for the rafter seat and the reduced depth of the tail is all one cut. The tail only has to be 3.5-in deep with a max 24-in cantilevered eave.
 
The tail end is not a diving board, not even a shade producer and it is spanned by plywood sheathing.
Only if a law suit was to evolve would it become a technical point of discussion and only then if it first led to some kind of deformation of the overhang.
 
As stated the overhand goes from 2x10 to 2x4 @ 3.5" in order to match the rafters coming from the soffit in the existing house gable. The span is roughly 16 feet so I think 2x10 is likely over built anyways, so the notch may be mute.

I am fine with either a ribbon or using painted brackets, it shouldn't detract too much from the overall aesthetic.
 
With your expert level of experience,

Nobody has ever said that before.

The work is stellar...it looks like they sanded the beam. If they hadn't used the one rafter with the wane, there would never be a problem of splitting and that one might have been a splitter no matter what.

The structure is a small overbuilt porch. You want a fix? ... I can think of several remediation efforts that could even look good.

One properly placed lag bolt could do it all but that fix will cost you. Really now, it's a porch and it is overbuilt. Whenever tall 2"X lumber is used, twisting and cupping should be anticipated...so yes it is a bit undone but a code violation? not so much.
 
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