# Caulking double studs on exterior wall??



## LINY11961 (Nov 9, 2011)

Hey guys need your help since I cannot find anything in the IBC about this. I was told that all double and triple studs that support outside walls must be caulked between them. Also,double top plates, sole plate to floor, headers to studs, jack and king, (headers already have 2"ISO board between), etc. House is 2x6 walls with 7/16 OSB covered with 1"ISO board on exterior and wrapped with Tyvek. Cap nails, tyvek brand tape, the whole 9 yards.

Make any sense to you? Nothing is going thru the ISO board and house wrap, right?. Walls will have 2" spray foam and 3 1/2" pink insulation when complete.

What do you think?????


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## Builder Bob (Nov 9, 2011)

What does the design professional say? It sounds like you may be in a hurricane region, high wind speed region, or a heavy seismic region.


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## knightj (Nov 9, 2011)

I belive this comes from the energy code, 2009 IECC sec 402.4- Air leakage & 402.4.1-Building thrermal envelope.


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## ICE (Nov 9, 2011)

LINY11961 said:
			
		

> Hey guys need your help since I cannot find anything in the IBC about this. I was told that all double and triple studs that support outside walls must be caulked between them. Also,double top plates, sole plate to floor, headers to studs, jack and king, (headers already have 2"ISO board between), etc. House is 2x6 walls with 7/16 OSB covered with 1"ISO board on exterior and wrapped with Tyvek. Cap nails, tyvek brand tape, the whole 9 yards.Make any sense to you? Nothing is going thru the ISO board and house wrap, right?. Walls will have 2" spray foam and 3 1/2" pink insulation when complete.
> 
> What do you think?????


No to most of that here in Ca. unless there are gaps.  The mud sill is supposed to be sealed unless there is a stucco weep screed.  I've seen it done as you describe and there is line after line of caulking with no gap to seal.


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## Pcinspector1 (Nov 9, 2011)

It could be a Farmers Home Admin/USDA or HUD requirement so the house can be sold under those loan progams? I know one of those programs had a requirement on vinyl siding mill thickness.

pc1


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## Examiner (Nov 9, 2011)

2006 IECC *402.4.1* addresses the *Building thermal envelope*.  If you have provided an air barrier over the sheating or the combined studs/post then I do not see requirements to provide caulk or sealant materials in the cavity space behind the air barrier for none pentrating items such as double studs. 402.4.1 does list paticular items as follows;

_The following shall be caulked, gasketed, weatherstripped or otherwise sealed with an air barrier material, suitable film or solid material:  _

_1. All joints, seams and penetrations._

_2. Site-built windows, doors and skylights._

_3. Openings between window and door assemblies and their respective jambs and framing._

_4. Utility penetrations._

_5. Dropped ceilings or chases adjacent to the thermal envelope._

_6. Knee walls._

_7. Walls and ceilings separating a garage from conditioned spaces._

_8. Behind tubs and showers on exterior walls._

_9. Common walls between dwelling units._

_10. Other sources of infiltration._

Part of the Commentary follow;

_The elements in this list include some of the largest sources of infiltration. Construction details not on this list must still be sealed by virtue of Item 10. As stated above, it is the continuity of all of the barrier items that ensure the building gets adequately sealed. _

Hope this is of some help.


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## Pcinspector1 (Nov 9, 2011)

Requiring double studs to be caulked, was'nt sure it was covered by the IECC?

pc1


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## LINY11961 (Nov 11, 2011)

Thanks for all your help. It may be something the insp likes to see so I'll make him happy. My architect said it wasn't necessary since the house will be so tight I'll need a HRV, but I just wanted to get your opinions.


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## Examiner (Nov 11, 2011)

In our area commercial contractors are not using the fabric wrap as much.  They are now using spray or roller/brush applied air barrier.  Too much labor to go back and repair the fabric after the winds have ripped it.

Attended a Lunch-n-learn yesterday and the manufacturer has a caulk gun applied material that is better than the fabrics used around the doors, windows and other penetrations of the sheathing.  Prosoco was the vendor and the product, air & water barriers, are not the acrylic type.

The product replaces tapes, that if not applied correctly wick moisture.  Some of you may want to review the product.  I think we will be changing our specs.

The product was shown to be used on many residential buildings as well as commerical.


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## KZQuixote (Dec 1, 2011)

LINY11961 said:
			
		

> Thanks for all your help. It may be something the insp likes to see so I'll make him happy. My architect said it wasn't necessary since the house will be so tight I'll need a HRV, but I just wanted to get your opinions.


I'd go with the architect. I suggest that you ask the inspector for the code section before I embarked on what must be hundreds of dollars of additional labor and materials.

It's not real.

Bill


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## High Desert (Dec 1, 2011)

LINY11961 said:
			
		

> Thanks for all your help. It may be something the insp likes to see so I'll make him happy. My architect said it wasn't necessary since the house will be so tight I'll need a HRV, but I just wanted to get your opinions.


Although I'm a B.O. I'm also an inspector and I hate it when a contractor did something that wasn't required by code just "to make me happy." I don't do "happy." I'd go with KZ and ask for a code section if the inspector is making you do it.


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## gbhammer (Dec 2, 2011)

High Desert said:
			
		

> Although I'm a B.O. I'm also an inspector and I hate it when a contractor did something that wasn't required by code just "to make me happy." I don't do "happy." I'd go with KZ and ask for a code section if the inspector is making you do it.


Inspectors can get something in their head and then they start to enforce the something with no code to back them up. It happens and when it does and the contractor calls me, I tell the contractor to ask the inspector for the code section. Continual training is the is the best way to keep those phantom codes out of the picture, but every once in the while you have to be reminded that your not perfect. This forum helps keep me straight every day.


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## skipharper (Dec 2, 2011)

I agree with KZ and High Desert--ask for the code section--I think we still have freedom of speech to some extent!! Building Inspectors are not trained to "what if", we read a book full of minimum requirements and enforce them.


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## tmurray (Dec 8, 2011)

I'm in Canada so I'm not certain how your code works, but here if someone is building with sprayfoam as a vapour barrier if they haven't caulked and sealed the joints of of the lumber I can ask for a blower door test. The thing is unless there are big gaps between lumber that haven't been sealed(never happens) it will pass with flying colours.

As a Federally Certified Energy Advisor I've preformed hundreds of blower door tests and this is generally what gives the best to worst seals;

1. ICF

2. Closed cell spray foam

3. Standard construction with foil backed expanded polystyrene taped joints

4. Standard construction

Just a note, I've seen brand new houses using standard vopour barrier preform as poorly as houses build 40 years ago.


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## Moscow (Dec 9, 2011)

our rule here is if a credit card can fit in the space you need to seal it.


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## tmurray (Mar 30, 2015)

Sorry to resurrect an old thread, but I received a PM from someone who is not a member and cannot respond, so I am placing my response here,



> Hi. I came across your post from 2011 about caulking between double studs on exterior walls when closed cell spray foam has been used. I am in a bit of a bind. A couple years back my husband and I renovated our recently purchased home (built in '62) in *****. We decided to completely go back to studs, reinsulate using CCSPF, new drywall, the works. Our home passed our insulation inspection without a peep from the inspector. There was absolutely no caulking applied at any joints and no 6ml vapour barrier as the spray foam is supposed to do the trick! However, with the lack of caulking we do not have a continuous vapour barrier and we have condensation forming in the wall cavity. Do you have any additional information related to Canadian code requirements that can support my case that the inspector should not have passed my house at inspection and that the insulating company screwed up?


I have edited the above to remove any confidential information.

Unfortunately the Ontario Building Code is a heavily amended version of the National Building Code, so the code reference that I have may not be the correct one. 9.25.4.1 states that a vapour barrier is required to prevent the diffusion of vapour from the inside to the wall,floor or ceiling cavity. I'm curious how you know it is due to condensation and not a water leak? The reason I'm asking is that generally diffusion through drywall provides a negligible increase in moisture levels inside the cavities and the National Research Council is contemplating the removal if the requirements of vapour barriers from the code entirely based on research into diffusion completed at the University of Waterloo. Basically, the amount of moisture that you would see from diffusion through the drywall should never be visible to the occupants of a building because it is so low. If you are seeing the moisture around your windows and doors it is much more likely that they have been improperly flashed and you are seeing the effects of water leakage. If you are seeing the moisture around the top of your ceiling at exterior walls (where the double top plate is) then you may have a moisture diffusion problem. If you have a moisture diffusion problem I would question your indoor air quality, as your relative humidity would need to be extremely high in order to generate that much moisture, in this case make sure your HRV is operating properly. Your indoor relative humidity should never be higher than 60% and I would recommend trying to keep it around 40% to prevent any buckling of your flooring and trim work.

Air leakage into the building enclosure carries an exponentially greater amounts of moisture than diffusion. In my jurisdiction we actually allow people building with a minimum of 1" foam on the exterior of the building to forgo the vapour barrier entirely as this creates a continuous air barrier on the exterior and moves the condensation point to lessen the risk of condensation on the cavity side of exterior sheathing.

Ultimately, if you are thinking of litigation against the city, you must prove that the building inspector should have noticed the missing air sealing at the double stud locations and that the lack of caulking was the source of the problem. It can be very challenging to prove that an inspector should have noticed a violation, as they are looking for so many things when doing an inspection. Also, you will need to do significant destructive testing must take place to confirm the origin of the moistureand enlist the services of an engineer who specializes in building science. To be honest, it is likely not worth the trouble and it may not be financially beneficial to sue the city.


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