2012 Springdale 189 Rotted floor. Anybody else?

[Del]

I bought a brand new Springdale 189 in 2012. It has only seen a handfull of weekend trips. Other than that it has been kept in my driveway. I have not used it for the past two years but periodically inspect the inside and outside for damage or leaks. I recently went into the trailer after 6 months of storage and the inside still looks like new, no smell, no water leaks. However, when I stepped from the front of the trailer towards the back, I found that most of the floor was extremely soft and rotted. Has anybody else had this issue? Something does not seem right. I have not even hardly used the trailer and it's only 4 1/2 years old.