Suggest immediate structural fix.ØSeal up 12 inch flue hole in garage roof to prevent rain and moisture from coming into garage space.  

Slabs are just not great things to put wood, laminate, or anything that can absorb moisture on.  

hello George,  the epoxy is actually for a basement floor to act as a sealant against moisture and keep dust down a little.

If you are concerned about water damage, you can buy higher quality laminate that can withstand moisture for 24 hours without any damage.  

---- and the wood-moisture-content of our floor system plummeted resulting in no mold/rot worries. 

Now floors have started buckling because of excessive moisture when site was wet. 

*Real world scenario:  I had a homeowner reach out to me as their basement had flooded (for a second or third time since they owned it - usually following excessive rainfall)... they had purchased a detached single family property that had been rehabbed and sold via the open/MLS market (so it may not have been sold as "as is")... the homeowner was surprised to learn that I had looked at that house when it was on the market (prior to being rehabbed) and shared with them the major mold problem that existed there (and therefore, moisture problem)... of course, with all the new basement walls and floor coverings...

Is the crawlspace treated for moisture (usually pea gravel and plastic) Is there free airflow between the crawl and the basement? 

It could be efflorescence on the grout from too much moisture. 

Wood doesn't really ever fail unless it's been compromised by cutting or moisture.