2009 IECC 402.4 Air Leakage (Proper Installaton)

[joetheinspector]

Can anyone answer or direct me to information in regard to proper installation of an air barrier per

2009 IECC 402.4 Air leakage

I have the following questions:

• 402.4.1 What is “an air barrier material, suitable film or solid material” (where can I find what meets this requirement of the code)?

• 402.4.1

o #5. dropped ceilings or chases adjacent to the thermal envelope (proper installation?)

o #7. Walls and ceilings separating a garage from conditioned spaces (is drywall that is taped an acceptable material? If so what about electrical boxes etc? Do the boxes need

to be sealed in some way? If drywall is not acceptable then what is?

o #8. Behind tubs and showers on exterior walls (Does the exterior air barrier cover this? Or does this require an air barrier on the inside of the wall?)

o #9. Common walls between dwelling units (just one side or both sides? Also is drywall an acceptable air barrier)?

o #11. Rim joist junctions. (does the exterior air barrier meet this requirement or is something else required?)

 

[Keystone]

Drywall may be used as an air barrier.

http://www.airbarrier.org/about/materials_e.php

 

[bptp32]

after a review of the code and our discussions with the DOE, IMHO i will offer the following. #1. air barrier --"air barrier is material(s) assembled and joined together to provide a barrier to air leakage throughn the envelope. may be an interior or exterior air barrier. exterior may be Housewrap, water resistive barrier or an equal component. we generally see the housewrap as the exterior air barrier (the installation details become the important factor); #5-- the code requires that fiberglass insulation be covered with a suitable air barrier component (interior drywall if sealed properly)-the code does not want to see the drywall stop at the soffit or chasewy and have the fiberglass exposed to air movement; #7 the common wall between the garage and the house should be treated as an exterior wal component. If the housewrap is eliminated then the drywall must be glued to the studs to act as an air barrier component. The penetrations shall be sealed as if located in an exterior wall; #8; Unless durorock or drywall is in direct contact with the fiberglass insulation, then the insulation must be covered with an air barrier component--we generally see housewrap or the fan-fold insulation that is generally used under siding as the air barrier behind a tub/showeer on an exterior wall. this requirement is to prevent air movement from reducing the stated r-value of the fiberglass insulation. (or any air permeable insulation); #8 common walls would be treated the same as any exterior wall system- we do not want tenant A's heat or cooling to impact tenant B; # 11 the rim joist area is very difficult to seal properly- we have seen a few contractors spray foam the rim area- we have also seen the exterior air barrier on the oputside suffice if installed properly-any gaps should be caulked or sealed;

 

[joetheinspector]

bptp32

Thanks for the great information. I am trying to get a understanding of the code requirements of air barriers and how to install fiberglass insulation properly, particularly in the case you mentioned on #8 in your answer ("to prevent air movement from reducing the stated r-value of the fiberglass insulation").

Do you have further information or do you know where I can find it as to the how/what causes the air movement and how it reduces the r-value. I think I almost grasp this concept, but not quite.

 

[mtlogcabin]

Not all house wraps are designed to prevent air movement through their product.

Check the specs before approving it as an air barrier

 

[bptp32]

Building Science Corp has some great articles on the requirement for air barriers and the convective loop that occurs if air permeable insulation is not in direct contact with an approved air barrier; try to cut and paste the following link and it may be of some help. The new energy code is the most difficult code revision in the past few years. We have had to go directly to the DOE to try and get clarification on a few of the energy code issues. MTlogcabin is correct. always check manuf specs for product applicability for the intended use. I have had to put together a few class room presentations to our local Home Builders Association to try and clarify and explain. Hopefully the link below will help.associationhttp://www.buildingscience.com/documents/information-sheets/installation-of-cavity-insulation/files/bscinfo_501_cavity_insulation.pdf

 

[joetheinspector]

bptp32

"I have had to put together a few class room presentations to our local Home Builders Association to try and clarify and explain."

That is what I am in the process of doing now. I have found that teaching the information is one of the best ways to learn the informaton.

 

[joetheinspector]

bptp32

Just got through checking out the link that you posted. That link has the information that I have been looking for.

THANKS

Now I know a thing or two about a thing or two.