Why Tyvek on an unconditioned corridor wall?

[Yikes]

I recently saw this detail for an new apartment project - -it's the wall between the unit and the corridor, so it's one hour rated and also STC 50+ sound rated.
The corridors are open near the ends and so it is unconditioned, but these walls are far within the corridor and not directly exposed to rain.
Why would there be tyvek on the warm / interior face of stud, underneath the resilient channels? Is it some kind of thermal bridging thing?

 

[RLGA]

Where is this project located? Could they be under the mistaken impression that Tyvek is a vapor retarder?

 

[Yankee Chronicler]

The notion that Tyvek is a vapor barrier (it isn't) is the only reason I can think of.

I would also like to see what 1-hour rated wall assembly was ever tested with Tyvek.

 

[Inspector Gadget]

Says it's a thermal wall. Is the corridor unconditioned space?

 

[RLGA]

Says it's a thermal wall. Is the corridor unconditioned space?

As stated by the OP, “The corridors are open near the ends and so it is unconditioned, but these walls are far within the corridor and not directly exposed to rain.”

 

[Inspector Gadget]

As stated by the OP, “The corridors are open near the ends and so it is unconditioned, but these walls are far within the corridor and not directly exposed to rain.”

So just an oversight by the designer, probably.

 

[steveray]

Air barrier or just the assembly they could find.....

 

[RLGA]

Air barrier or just the assembly they could find.....

Possibly, but 5/8-inch gypsum board is considered an air barrier by the ABAA.

 

[steveray]

Even though the wall is not "exposed", I do not believe there is actually an exception to not build it like any other exterior wall, other than the general "weather resistant" terminology...:

1402.2​

Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing, as described in Section 1404.4. The exterior wall envelope shall be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.

Exceptions:

1. 1.A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
2. 2.Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall envelope that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:

 

[RLGA]

The problem is that the Tyvek material is indicated to be installed behind the inside gypsum board, so it is not being used as a water-resistive barrier in this instance.

Tyvek, commonly used as a water-resistive barrier, is typically installed over the gypsum sheathing, behind the cladding and continuous insulation (if any).

My guess is that it is used as an air barrier with the expectation that the interior gypsum board could experience punctures from hanging wall decorations, etc.

 

[steveray]

The problem is that the Tyvek material is indicated to be installed behind the inside gypsum board, so it is not being used as a water-resistive barrier in this instance.

Tyvek, commonly used as a water-resistive barrier, is typically installed over the gypsum sheathing, behind the cladding and continuous insulation (if any).

My guess is that it is used as an air barrier with the expectation that the interior gypsum board could experience punctures from hanging wall decorations, etc.

true enough...didn't look that closely....

 

[Yankee Chronicler]

Tyvek, commonly used as a water-resistive barrier, is typically installed over the gypsum sheathing, behind the cladding and continuous insulation (if any).

I have always regarded Tyvek as an air infiltration barrier, not as a water barrier.

 

[RLGA]

I have always regarded Tyvek as an air infiltration barrier, not as a water barrier.

 

[Yikes]

My guess is that it is used as an air barrier with the expectation that the interior gypsum board could experience punctures from hanging wall decorations, etc.

In that case, would it make no difference to put in on the exterior/unconditioned side?

 

[RLGA]

In that case, would it make no difference to put in on the exterior/unconditioned side?

Yes, it would be better in that location as an air barrier.

I asked about the location, but I did not get a response. If this building is located in a cold climate area, then a vapor retarder on the inside is the probable location, which has a small part of me thinking they intended to use the Tyvek as a vapor retarder. Tyvek is a good barrier to liquid water but is a lousy vapor retarder (~28 perms for its CommercialWrap to ~54 perms for its HouseWrap).

 

[Yikes]

Yes, it would be better in that location as an air barrier.

I asked about the location, but I did not get a response. If this building is located in a cold climate area, then a vapor retarder on the inside is the probable location, which has a small part of me thinking they intended to use the Tyvek as a vapor retarder. Tyvek is a good barrier to liquid water but is a lousy vapor retarder (~28 perms for its CommercialWrap to ~54 perms for its HouseWrap).

Sorry, building is in Southern California, Pomona Valley area, rather temperate. Maybe it got copy/pasted from a cold climate project.

 

[redeyedfly]

If i

Yes, it would be better in that location as an air barrier.

I asked about the location, but I did not get a response. If this building is located in a cold climate area, then a vapor retarder on the inside is the probable location, which has a small part of me thinking they intended to use the Tyvek as a vapor retarder. Tyvek is a good barrier to liquid water but is a lousy vapor retarder (~28 perms for its CommercialWrap to ~54 perms for its HouseWrap).

If it was a good vapor retarder, it would be an awful housewrap.

 

[steveray]

If i

If it was a good vapor retarder, it would be an awful housewrap.

Some might argue that it is an awful housewrap.....

 

[Paul Sweet]

"If it was a good vapor retarder, it would be an awful housewrap."

Except in the deep South.

 

[Penguin87]

I recently saw this detail for an new apartment project - -it's the wall between the unit and the corridor, so it's one hour rated and also STC 50+ sound rated.
The corridors are open near the ends and so it is unconditioned, but these walls are far within the corridor and not directly exposed to rain.
Why would there be tyvek on the warm / interior face of stud, underneath the resilient channels? Is it some kind of thermal bridging thing?


View attachment 14277

You say the corridors are open to the exterior atmosphere, correct?

Tyvek is an air barrier - building code requires an air barrier between conditioned and unconditioned spaces.
The Tyvek should be installed on the exterior side of the wall assembly.

Perhaps the architect thinks that Tyvek is a vapor barrier. It is not. If the building is in a climate zone (cold climate) that requires a vapor barrier on the interior wall assembly, then they will additionally need a vapor barrier on the interior side.

 

[Tim Mailloux]

the "install in compliance with code section referenced below" notations in that architects wall type really annoy me. Its the architects responsibility to detail the wall assembly to comply with the code requirements, not to put that responsibility on the builder.

 

[mtlogcabin]

Tyvek is a code compliant water resistant barrier.

[RB] WATER-RESISTIVE BARRIER. A material behind an exterior wall covering that is intended to resist liquid water that has penetrated behind the exterior covering from further intruding into the exterior wall assembly.

R703.1.1 Water resistance.
The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior cladding as required by Section R703.2 and a means of draining to the exterior water that penetrates the exterior cladding.

https://www.dupont.com/content/dam/dupont/amer/us/en/performance-building-solutions/public/documents/en/install_guide_residential_WRB_open_stud_southwest_43-D100701_enUS.pdf

 

[Joe.B]

I'm in Climate Zone 1, near the ocean. I've seen quite a few walls get opened up due to some kind of rot and/or water damage. Every time they run into tar paper (usually 30 lb felt) the damage stops at the wrap, everything behind the paper is perfect. Anytime they encounter Tyvek, the damage continues right on through to the framing. Sometimes it even looks worse behind the wrap.

 

[Yankee Chronicler]

the "install in compliance with code section referenced below" notations in that architects wall type really annoy me. Its the architects responsibility to detail the wall assembly to comply with the code requirements, not to put that responsibility on the builder.

Yes!

See the last portion of IBC 107.2.1 as adopted by Connecticut. I cite that a LOT.