I'm a little late to the party on this thread but wanted to add my thoughts. I'm quite surprised at the number of folks here who are defending Heartland on this issue. Don't get me wrong, we love our BH, but if this had happened to us I would have gone berserk. And I'm not a berserk kind of guy...
Wharton, why on earth would a customer be expected to know about this type of structural delamination? I agree that a customer must be responsible for maintaining his rig (not an easy task) but that seems beyond the scope of what you could expect a customer to be aware of.
Heartland directing the customer to Parkland plastics for warranty coverage is absurd. Parkland's product was not being used properly. This is a Heartland manufacturing error.
I realize that no RV company is perfect... far from it. This is a very badly broken business model. The whole idea of requiring customers to interface with Tier II vendors is craziness. Think about an automobile for a minute. If you bought a new GM truck and the fuel pump went bad after a month, and the manufacturer told you to call their supplier for help, you'd go nuts. Why RV's are so different is beyond me. It's at least 30 years behind the car industry.
So back to the OP. What good is a one year warranty for issues that take time to develop, such as this one, due to a manufacturing defect. To me, this one should be obvious. We're not talking about a window that started leaking due to dried out caulk 18 months down the line. We're talking about something that was wrong from DAY ONE, and it took 18 months before OP realized the damage it was causing. You could argue that he may have found it sooner, but I'm not so sure that on a lightly used unit this problem would become apparent in a year's time or less.