# Notching Exterior Top Plates



## jar546 (Aug 7, 2019)

This is a structural and energy issue since this is an exterior, load bearing wall.  What say thee?


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## e hilton (Aug 7, 2019)

I “think” you could get around the structural issue with proper strapping and bracing ... but that strip of sheet metal doesn't fly.


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## Pcinspector1 (Aug 7, 2019)

I believe it should be 18 gauge steel with a minimum of 8 compliant nails on each side into the top plate. Am I missing something? 

I don't think it's an oval flue and the insulation appears to be installed poorly not filling the wall cavity properly.


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## jar546 (Aug 7, 2019)

Pcinspector1 said:


> I believe it should be 18 gauge steel with a minimum of 8 compliant nails on each side into the top plate. Am I missing something?
> 
> I don't think it's an oval flue and the insulation appears to be installed poorly not filling the wall cavity properly.



Yeah, how will they get insulation against the rim board?


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## tmurray (Aug 8, 2019)

That insulation behind the duct doesn't look compressed at all. Definitely still has the full insulation value.


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## e hilton (Aug 8, 2019)

tmurray said:


> That insulation behind the duct doesn't look compressed at all.



If the stud is 2x4 ... then the insulation is only 2” thick.


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## HForester (Aug 8, 2019)

For buildings constructed to the IRC, see IRC Section R602.6.1.


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## mtlogcabin (Aug 8, 2019)

Code compliant for notching

R602.6.1 Drilling and notching of top plate.
When piping or ductwork is placed in or partly in an exterior wall or interior load-bearing wall, necessitating cutting, drilling or notching of the top plate by more than 50 percent of its width, a galvanized metal tie not less than 0.054 inch thick (1.37 mm) (16 ga) and 11/2 inches (38 mm) wide shall be fastened across and to the plate at each side of the opening with not less than eight 10d (0.148 inch diameter) having a minimum length of 11/2 inches (38 mm) at each side or equivalent. The metal tie must extend a minimum of 6 inches past the opening. See Figure R602.6.1.
Exception: When the entire side of the wall with the notch or cut is covered by wood structural panel sheathing.


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## Pcinspector1 (Aug 8, 2019)

Sorry wrong gauge listed, should be 16 ga.

Exception does not apply here unless the notched side or cut is being covered with SPS.

Looking at the top plate it appears the insulation behind the duct does not fill the cavity, IMO.


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## ADAguy (Aug 8, 2019)

Shouldn't there be double studs on either side of the duct? and is the condition actually a two story?


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## mtlogcabin (Aug 8, 2019)

Because of our seismic zone all homes are constructed with
CS-WSP
Continuously sheathed wood structural  panel


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## Glenn (Aug 8, 2019)

Ditto on the previous comments about the notched plate.  In addition, no paper facing installed that way.
IRC 302.10.1, exception 1: "...provided that the facing is installed in substantial contact with the unexposed surface of the ceiling, floor or wall finish."


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## e hilton (Aug 8, 2019)

mtlogcabin said:


> Exception: When the entire side of the wall with the notch or cut is covered by wood structural panel sheathing.



So ... minutiae... when it says “side of the wall with the notch” ... referring to the picture it looks like sheathing in the other side of the studs, so does that meet the requirement or doees it need sheathing on the near side?


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## ADAguy (Aug 8, 2019)

"side" as in typically one side only.


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## Pcinspector1 (Aug 8, 2019)

Jar, Is that Advanced Code Group photo copyrighted? 

I think all put my PJ's, get a coke and a piece of pizza and design a picture book, kinda like Upcode did!

"Pajama Pirates!"


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## jar546 (Aug 8, 2019)

Pcinspector1 said:


> Jar, Is that Advanced Code Group photo copyrighted?
> 
> I think all put my PJ's, get a coke and a piece of pizza and design a picture book, kinda like Upcode did!
> 
> "Pajama Pirates!"



yes it is.  Do you need to use it?


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## steveray (Aug 9, 2019)

I'm with MT....Struggled with it at first, but technically there is on limit to the notch (100%), so it matters not which side the plywood is on....As far as the insulation is concerned, we normally overlook "small" deficiencies, but that will be different for everyone...I thought we used to have something that said the ducts had to be separated from the exterior by at least R8 like the attic, but I don't see it anymore.


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## mtlogcabin (Aug 9, 2019)

The energy code would require a minimum R-6 since it is not within the building thermal envelope. You could even require the R-8 but you might get push back from a contractor since it is not "outside" the building thermal envelop.

If it is a "B" vent then you don't want any insulation around it


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