Beginning about 6 weeks after a nail down 2nd story install over plywood, several boards of solid 5/8" bamboo began to turn a very deep yellow. The discoloration does not extend accross the entire board and looks as though someone has made a swipe with a paintbrush loaded with yellow paint. It took a period of about 3 months for 16 boards to show this distinct marking. There is no obvious pattern to their location: they are scattered through 3 rooms. None see direct sun, some are under area rugs, some see foot traffic, some have never been walked on. No water or cleaner have been used, only dry mopping. In looking at the end of a cut board, it appears that the staining is about 1/8" deep in the board's top layer of wood. The floor's manufacturer, Greenwood, sent out an inspector who checked ambient conditions, board moisture, etc. He concluded that it was an installation problem that was caused by asphalt contamination from the roofing felt underlayment and/or the reseal of the asphalt street outside. Since the roofing felt is commonly used (and required by Greenwood's own instructions) and the street reseal occured months after the problem was noted, the installer brought in another inspector who concluded that the problem was definitely in the boards. He claims, however, that the Greenwood warranty sells their product "as-is" and there is no recourse. Greenwood is sticking to the claim of insallation error. Has anyone seen this discoloration before? Anyone have experience with the "as-is" clause in the Greenwood warranty?

Thanks

Yikes, is right.

The first inspector wasn't very versed, and sounds biased towards the manufacturer!!

From your description, it would be difficult to give that problem a label.
Are the edges of these different colored bands straight?
I'm sure the yellowing is in the boards, by your description, but how did it get there?

Thanks for the reply. The staining tends to be somewhat straight along the length of the boards, but it also generally crosses a few of the individual strips of bamboo in the boards. It never quite goes accross all of the strips in a given board. The line of discoloration is very distinct with no transition to a normal color. It looks so much like a paintbrush swipe on some of the boards that I almost wonder if it is something like the adhesive between the board layers leeching up through the top layer.

Facts:
1. Darker yellowing color.
2. Straight along edges.
3. Penetrates into bamboo to 1/8".
4. Crosses filet joints.
5. Not full width of plank.
6. Paint brush appearance.
7. Randomly located in different rooms.

Crossing the filets would indicate the contaminant causing the yellowing was after manufacturer, but not necessarily after finish applied.
Something got on the surface of the bamboo after manufacture or after finishing. They were in various boxes, by the statement they were in various rooms.
At any rate.. take the boards out and put new boards in. My GUESS would be you have a manufacturing issue.
Thank you for the post and information. This is not one I've seen yet.