Does the 2003 version of the IECC or IRC require any type of “house wrap”?
The way I think I read the code is that it is not required. Please give me the law to follow. look this up in the IRC N1102.1.10
brian,
u need to check out IRC R703.1-R703.4 and the table R703.4
IRC R703.4 chart
I have vinyl siding exterior covering, so The way I read this, is it is not required. Do I have a " I agree" out there?
This is in all my reports: “The wall sheathing beneath the siding may or may not be covered with a water proofing membrane, commonly called “house wrap”. While not required, it is recommended but we do not verify its presence or absence.”
House wrap is not required as a weather barrier under vinyl siding under the 2003 IRC…but an air barrier IS required under the 2003 IECC + 2003 IRC unless one uses other acceptable means to prevent air infiltration into the structure.
See Table R703.4 that sheathing paper is not required under vinyl siding,
Refer to N 1102.1.10 “Air Leakage” regarding the need for an air barrier or other methods to prevent air infiltration and exfiltration.
So the correct answer is, that housewrap is not required under vinyl siding as a secondary weather barrier but is required as an air barrier if the owner has not sealed all joints between sheathing and studs and other framing members to restrict air flow.
Mine was the correct answer relating to what the IRC 2003 and IECC 2003 required and did not require.
Doesn’t mean that what I cited was the best practice.
The original question was whether or not the 2003 IRC or IECC required ‘housewrap’.
The correct code answer is as I cited above.
One should not forget that the IRC and relative Codes are the bare minimum and nothing to prevent from expecting better standard of quality installations.
The Codes are written to protect the Consumer with the bare requirements of Building.
We are not Code Enforcement Officers and should just note and report what we see as to the condition of the Building.
But for your information I have provided this below:
Vinyl siding is not waterproof, despite common misconceptions. Thanks to its overlapping profile, a standard interlocking wall of horizontal vinyl panels will effectively shed most rain and water away, providing superior water resistance. However, no vinyl siding is completely impervious to outside moisture from dampness rain or snow. For that reason, siding panels are manufactured with “weep holes” located at the bottom of each panel projection edge. These small but important outlets help channel away water that might find its way inside the siding wall through the panel seams and around moldings, windows, door and fixtures.
Weep holes also allow the infiltration of air, which also helps to dry out the inner surface of the siding while promoting evaporation of any remaining moisture. The application of house wrap and or insulation board also provides for a secondary defense against outside moisture that might penetrate the siding and come in contact with the original sheathing.
Look for weep holes in the butt, which allow any incidental moisture or water vapor to escape. At the same time, it’s important to keep rain from getting behind the siding. That means flashing must be correctly installed at windows, doors and gables. To address moisture retention that can lead to mold or rot, homes should be swaddled in a breathable house wrap.
Hope this helps.
Marcel 
Many vinyl siding manuf’s. are now requiring house wrap for warranty purposes. Requirement by manuf. makes it code right?
Bruce, you are correct, it would make it a Manufacturers Code to protect their product and the Manufacturers product under that also.
Code as one looks at it is a minimum quality standard of practices in the Building Industry.
Marcel 
Maybe not covered by code but required by the manufacturer.
http://www.vinylsiding.org/publications/Installation_Manual_english.pdf
IMPORTANT NOTES
Weather Resistant Barrier
Vinyl siding has always been designed as an exterior cladding, not a weather resistant barrier.
***Vinyl siding is designed to allow the material underneath it to breathe; therefore, it is not a watertight covering. ***
Because of its design and application, it provides a supplemental rain screen
that enhances the weather resistant barrier system by reducing the amount of water that reaches the underlying weather resistant barrier.
***What Is a Weather Resistant Barrier System? ***
It is a system that includes water shedding materials
and water diversion materials. Weather resistant barrier systems commonly consist of a combination of exterior cladding, flashed wall openings and penetrations, weather resistant barrier material, and sheathing. Effective weather resistant barrier systems will shed the water initially, control moisture flow by capillary and diffusion action, and minimize absorption into the wall structure. The level of weather resistance required is determined by the applicable building code and structure
***Best Practice: ***
*To achieve designed performance, vinyl siding must be installed over a weather resistant barrier system that includes *
*1) a continuous weather resistant material and *
*2) properly integrated flashing around all penetrations and where vinyl siding interfaces with other building products such as brick, stone, or stucco. *
Refer to the manufacturer’s installation manual for specific product applications and recommendations. Whichever product(s) you decide to use as part of a weather resistant barrier system, be certain the materials meet the applicable code by contacting the manufacturer of the weather resistant barrier material(s). Always consult the applicable building code for minimum weather barrier requirements in your area. Keep in mind that additional measures may provide better protection against water intrusion than the minimum requirements of the building code.
Please note that under the IRC 2003, no water resistive barrier was required under vinyl siding.
That changed under the 2006 IRC. A Water Resistive Barrier is now required by Code under vinyl siding. See Table R703.4.
Note also, however, that in Pennsylvania, vinyl and aluminum siding is exempt and excluded from complinace with the State Uniform Construction Code when installed on an existing residential or commercial structure…unless such installations are regulated by local amendment.
This means that vinyl and aluminum siding installations on existing buildings are completely unregulated in most of Pennsylvania.
See section 403.1 (b) (10) of the Pennsylvania Uniform Construction Code:
http://www.dli.state.pa.us/landi/cwp/view.asp?a=310&q=211697#403.1
Not unless Code specifically overrules the maufacturer’s installation instructions…
Most manufacturer’s installation instruction defer to local code requirements.
As you suggest, the abscence of code does not negate the Manufacturer’s recommendation.
The Manufacturer’s requirement/recommendation then becomes the minimum standard if the Code does not address or falls short of reasonably expected.
Do you build in PA?
Builder and Code Inspector in Pennsylvania, Mr Haggarty.
Pennsylvania makes this ‘ugly’ by exempting vinyl and aluminum siding (on existing structures) from code compliance in the Commonwealth.
In such cases, the manufacturer’s installation instruction would rule and it becomes an issue between the homeowner and the builder alone.
In other cases, the PA UCC would take precedence, and one would have the power of the law to assist in enforcing compliance.
In Pa, it becomes a municipality by municipality thing, and a manufacturer by manufacturer thing on existing structures.
All new construction siding in Pa as of 1-1-07 must have a water resistive barrier behind it…period.
PS: I am aquainted with one of your HouseMaster Inspectors in my region and we typically refer to one another.
I’ve been impressed with HouseMaster in regards to their training…
Builder and Code Inspector in Pennsylvania, Mr Haggarty.
Pennsylvania makes this ‘ugly’ by exempting vinyl and aluminum siding (on existing structures) from code compliance in the Commonwealth.
In such cases, the manufacturer’s installation instruction would rule and it becomes an issue between the homeowner and the builder alone.
In other cases, the PA UCC would take precedence, and one would have the power of the law to assist in enforcing compliance.
In Pa, it becomes a municipality by municipality thing, and a manufacturer by manufacturer thing on existing structures.
All new construction siding in Pa as of 1-1-07 must have a water resistive barrier behind it…period.
PS: I am aquainted with one of your HouseMaster Inspectors in my region and we typically refer to one another.
I’ve been impressed with HouseMaster in regards to their training… 4/1/07 5:07 PM
This seems contradictory to your previous post.
Appears like an ambiguous assesment and interpetation of the Codes.
I like to note what I see at an inspection and write it as hard as I can. I will leave the interpretation of Codes to the ones that don’t have to inspect the condition of a building.
Code Compliance can and will be left to the one’s holding that title.
The interpretation might not always be accurate, but I can live with that just like I can live with someone interpreting the specifications on what I build.
I just hope they did their homework. Sometimes they will discover that their specification writer took some short cuts and a boiler plate specification is born. I have always said that commen sense will go a long ways. Building paper is been under siding material of any kind for as far back as I can remember. That was not last year. And If I need too, I can access material from my teacher that goes back to 1933 in the Contruction trade. 
Marcel 
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Marcel R Cyr said:
That is unfortunate for you…
Here is one such example:
Certainteed vinyl siding installation instructions DO NOT require housewrap or felt paper under any of its vinyl siding products for either new construction or remodeling applications…
The manufacturer’s installation instructions only require that the structure be “watertight”:
http://www.certainteed.com/NR/rdonlyres/732CB081-EE5F-4768-9374-D7C9BAC8BA02/0/cts205b.pdf
Watertightness of a structure can be achieved in many ways that do not include housewraps, building papers, or any other type of secondary weather resistive membranes.
The 2006 IRC, however, requires a “water resistive barrier”…a requirement that actually goes BEYOND what the manufacturer’s installation instructions require.
See Table R703.4 and sections R703.2 & R703.6.3 where you will find that the 2006 International Residential Code is actually more restrictive than the manufacturer’s installation instructions (MIIs)…and where the Code takes precedence over the MIIs…
[FONT=Times New Roman]Using the link that you provided…
http://www.certainteed.com/NR/rdonlyres/732CB081-EE5F-4768-9374-D7C9BAC8BA02/0/cts205b.pdf
"Vinyl siding is an exterior cladding; it is not a complete
weather resistant barrier. Before applying siding, make
*certain the substrate is *[/FONT]watertight. In order to be protected
from precipitation, the substrate may need to be properly
flashed around areas such as windows, doors, other openings
*and corners so as to shed water to the exterior. ***[FONT=Times New Roman]The siding
[size=3]alone is not meant to be a watertight barrier."
**
You suggest " Watertightness of a structure can be achieved in many ways that do not include housewraps, building papers, or any other type of secondary weather resistive membranes."
Examples?
**[/size][/FONT]
Sure.
T1-11 siding using Z-flashing is considered ‘watertight’…
Board and batten siding is considered ‘watertight’…
Clapboard siding is considered ‘watertight’…
You could go over any of these existing wall coverings in a remodeling application without the use of housewraps or felt paper and still meet Certainteed’s MIIs…
For new construction, you could actually seal all joints in the sheathing using caulks and/or waterpoof self-adhereing flashings and still meet the MIIs without housewrap or felt paper for Certainteed Vinyl siding.
Rigid foam sheathing with taped joints would also meet Certainteed’s MII requirements for ‘watertight’ new construction.
The 2003 International Residential Code recognized the fact that ‘watertightness’ could be achieved in many ways which is why, in part, the 2003 IRC did not require a “water resistive barrier” under vinyl siding.
The 2006 IRC, however, went a step beyond even many MIIs by requiring a ‘water resistive barrier’ where even the manufacturer requires none.
Currently, as in the case of Certainteed Vinyl Siding, the IRC 2006 overrules the MIIs and is more restrictive than the MIIs.
Certainteed is a prime example where the MIIs are actually LESS restrictive than prevailing codes.
It is unfortunate that some do not understand why and how Codes are written.
Ceertainteed may not require a building wrap under their Product, and this is mainly due to the fact, they do not need a weather barrier to warranty their product one way or the other.
The key here is Commen Sense and the fact that the weather barrier is there to protect the building wall assembly and not the siding.
Would it not make sense to notice that is why the code was re-written to provide a weather barrier to protect what is under the siding material whatever that might be?
Marcel
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