Greetings,
We live in north central Connecticut. In the spring of 2006 we had a very nice - and expensive - multi-level deck installed. It is made of PT pine. It faces southwest so it gets full sun from 9am-4pm during the summer. The lowest tier of the deck is about 4 feet off the ground. The highest tier attaches to the house and is about 8 feet off the ground. It is all well ventilated underneath. We have been very diligent about getting it pressure washed and re-sealed every 12-18 months.

After a couple of years we had to have some boards replaced because they were checking and warping. That continued. A couple of years after that, we had to replace a few boards because they were rotting. Now it seems to have turned into a epidemic of rotting boards. I count 13 boards that have either been replaced or need replacing. Some boards are the decking, some boards are hand rails, some boards are facia. The deck that was on the house previously was the original deck that had been there since 1987. It wasn't showing any signs of rot.

My questions are 1) are these symptoms of a bad batch of pressure treated lumber, and 2) has anyone else experienced the same thing?

We brought this to the attention of the deck builder and he said it was bad lumber. We contacted the pressure treater and without saying it was bad lumber, he said that we could request replacement lumber. The builder will happily do the repairs, but since we're out of warranty he will charge us. He's not inexpensive. I don't want to get into an annual cycle of replacing a board here and a board there until eventually the whole deck is replaced. I'll end up paying for the deck twice!

The attached photo shows the rotting end of one board (the black stain) that is under the highest level, is well ventilated, and is completely protected from direct exposure to sun and precipitation.

This has been a much longer post than anticipated. If you've stayed with me this far, thank you. Any thoughts from the community are appreciated.