Water-Resistive Barrier per Sec. 1403.2

[indyarchyguy]

This is for a new Storage Building Project in Ohio - 2017 OH Building Code (2015 IBC with Amendments). The building is a new, S-1 facility, one-story, Type II-B, non-climate controlled storage facility. Typical storage facility with exterior overhead doors. Essentially a pre-fabricated metal building with a combination of metal panels approximately 36-inches wide which extend from the bottom of the roof drip down to approximately 3 feet above the ground. The wainscot is made of thin veneer stone which is applied to a plastic backer panel that is fastened to the metal purlines (steel hat channels). There is a metal flashing drip edge between the metal panels and the top of the stone veneer panels. The stone veneer panels have a bottom metal edge that sets in a continuous, full bed of sealant (butyl) as they are installed. The stone elements overlap the next panel to hide the joint between the plastic panels. Both the metal panels and stone panels shall be installed to hat channel purlins.

The building inspector has insisted that the water-resistive barrier must be applied prior to the installation of the metal and stone panels per Sec. 1403.2 which directs you to 1404.2:

"1404.2 Water-Resistive Barrier
Not fewer than one layer of No.15 asphalt felt, complying with ASTM D226 for Type 1 felt or other approved materials, shall be attached to the studs or sheathing, with flashing as described in Section 1405.4, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer."

Needless to say, there has been an abundance of these prefabricated structures supplied all over the country and have been erected and installed in Ohio. According to the Owner/Client who owns several of these in Ohio, this is the first time this issue has cropped up. Both I and the Architect have agreed that providing a barrier directly on the studs doesn't really make sense. While technically it will meet the spirit of the code as written and the overall requirements of 1404.2, we both do not believe it will last through the overall panel systems installation process. There is no insulation in the walls as this is not a climate-controlled building. There will be some bagged insulation installed immediately behind the metal roof system as part of the metal building manufacturer's overall system, but it is minimal only to reduce heat gain.

When I review Chapter 14 in the 2018 and 2021 IBC's, it appears to me that the ICC has realized this and modified Section 1404 by adding Table 1404.2 for protection provided by different veneer elements as long as they provide a minimum thickness. We reviewed the metal panels and the stone veneer panels and have determined they exceed the thickness requirements for their respective elements and there is flashing between the elements. I have further suggested we provide butyl tape between each vertical joint (the metal panel that overlaps the adjacent metal panel) and at the stone panels. Sealant is provided at the bottom of the stone composite panel with a built-in metal drip. This would then eliminate the requirement for a water-resistive barrier.

I am just trying to determine if I am missing something in the current code, as well as if I am reading the 2018/2021 code modifications correctly. Thank you.

 

[ICE]

The following code indicates a potential lack of a moisture barrier behind the steel cladding. As to the stone veneer, well you'll have to look further for an answer to that. The stone veneer being a plastic backed panel lends itself to a dispensation from a moisture barrier. Perhaps not officially but practically.


1404.11.2 Weather protection. Metal supports for exterior metal veneer shall be protected by painting, galvanizing or by other equivalent coating or treatment. Wood studs, furring strips or other wood supports for exterior metal veneer shall be approved pressure-treated wood or protected as required in Section 1402.2. Joints and edges exposed to the weather shall be caulked with approved durable waterproofing material or by other approved means to prevent penetration of moisture.

1402.2 Weather protection. 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.

In my youth I spent several years working for Morton Buildings. Pole barns in Illinois and environs. I do not recall any moisture barrier in walls or roofs. It was the second most dangerous job that I have had.