Temporary rain protection for open floor deck – GreenBuildingAdvisor

I am working on a project with an advantech subfloor.  For various reasons it won’t be enclosed for about 2 months. We recently got a good bit of rain and mold has already formed on the underside of the subfloor.  The basement/crawl is designed as a conditioned space so no vents.

my question is can we protect the deck for the two months with a liquid applied membrane such as prosoco or similar? Would this cause more damage as it makes it harder for the moisture to evaporate or would the resistance to the bulk water intrusion outweigh the cons? 

for context we are in the south and the rainy season is just starting. we are installing fans and two dehumidifiers to mitigate the effects but I can’t help thinking keeping most of the water out and not giving it a chance to absorb into the subfloor might be a great solution.

anybody done something like this before that could offer some insight would be greatly appreciated 

thanks