Best Moisture Barrier Under Hardie Siding

A wrb is more of a water and moisture resisting barrier than a vapor resisting barrier and it also serves when installed correctly as a drainage plane for water and moisture get behind the siding as will happen.

Best moisture barrier under hardie siding. Hardiepanel vertical siding. Water will remain between the siding and the moisture barrier for a time but it will eventually dry out rather than soaking into interior wall parts for the long term. Hardie plank recommends a maximum of 1 of foam board celotex type material under their lap siding so the 1 2 foam and 1 2 celotex would be fine. They will breath and excessive moisture should escape through the exterior siding.

If your contractor installs hardie siding when it s saturated it may show signs of shrinkage or even staining over time. Tyvec is not a vapor barrier it is an air penetration barrier just like the new zip system. Hardiebacker cement boards. According to joseph lstiburek with the building science corporation the ideal wrb perm for balancing the inward and outward flow of moisture in a wall system is between 10 and 20 perms.

Also by james hardie. A high perm means the wrap has high vapor permeability. Ultimately the back of. Depending on how it s hung house wrap can either act as a moisture or wind barrier.

When used to slow winds its job is to seal gaps and leaks in the osb panels or plywood sheathing that makes up your home s exterior walls. Hardiewrap weather barriers. They both stop liquid water infiltration but water vapor is a different story it must be able to pass through. Luckily it takes lots of water to saturate hardie products.

Also by james hardie. That keeps drafts from reaching your insulation and prevents heated and cooled air from seeping out through the walls. But it can t be so high that the moisture can penetrate from the outside into the wall system. Superior adhesion hardiewrap flashing adheres to sheathing and housewrap even in extreme temperatures and contains no asphalts vocs volatile organic compounds or solvents which can reduce adhesion over time.

In order to increase the insulation values i want to first add a layer of the rigid foam board. The best protection against condensation and moisture infiltration into the wall system of a steel sided building is the application of a high quality house wrap that meets and exceeds the requirements of the ibc 1402 2 and irc r703 1 1 for weather resistant barriers like barricade building wrap. Would it be better insulation if i remove the celotex and use a 1 foam board instead. Install tech docs.

Install tech. Hardie siding does a great job of wicking moisture when it is installed on the wall but when it s uncovered and flat on the ground it will absorb water. Hardieplank does not require a vapor barrier it requires a weather resisting barrier wrb.