I am about ready to get bids on my SIP house and would like to hear from some pros on the osb/mold issue.  Since osb makes for great mold food I am concerned that house wrap and Hardie board alone will not prevent mold from finding a home on the exterior osb face of my house (warm & humid in summer).  I have been thinking of finding an anti mold/mildew paint/coating that I could spray on before wrapping the house.....any comments?  And while we are on the subject, some SIP suppliers require that a vapor barrier be used on the inside osb face before drywall.  My thinking is that with foam on one side of the osb and a vapor barrier on the other if any moisture did get into the osb with this set-up mold would be more likely to grow than if the inside face were free to breath...more comments?  By the way I intend to have ac and always like to keep my indoor humidity between 40 & 50%.

Thanks,

DP

Although there are lots of home built with SIPs and even conventional that won't get mold with a well installed drane plane system, you could look at steel SIPs as an alternative to a spray on paint. It might cost less for the upgrade. And one of the reasons I shy away from SIP roofs is that issues with the install are more likely here then in the walls.

good reason why I use steel SIPs on walls and roofs, the skins are a natural vapor barrier which do not support mold growth, do not require splines, will not warp or swell if exposed to the elements, weigh much less not requiring a crane