Any experiences or recommendations appreciated. Based on pictures and descriptions, this may be our issue as I posted in the 'Finish Concerns' thread but we're still looking at all possibilities. (BTW, the floor rep thinks that the finisher used MasterLine satin over the Zinsser Shellac sealer but that's not certain.)

Thanks for any input.

normally with wls the poly is still bonded and has stretched over the gap, happens more with waterborne finishes than oil. Can happen with oil just not as many cases.

What is the cause of white line syndrome? How can you keep the flooring from shrinking in the winter time? Just because a finisher used some product does not mean he is liable because you allowed the relative humidity in your house to drop to single digits. People need to take care of their wood. Not ignore it's needs for moisture in the winter.

While we are not certain our condition would be deemed 'white line syndrome', it seems to share many characteristics based on the descriptions and photos we've seen. As far as the cause, that's why I posted; just a homeowner here. We are continuing to garner as much information as possible and consider all the variables including products, application processes and environmental. And we do understand seasonal expansion and contraction. Something more is happening here. (FYI: This is a newly constructed NAHB Gold-certified home with humidifiers, dehumidifiers, geo-thermal, foam insulation, etc. While I cannot give you an exact reading at the moment, the humidity levels in this home have not been in the single digits.)

WLS is caused when the film is stretched instead of fracturing. Poly by design should have some flexibility to it but, too much and it doesnt break clean along the seams under normal seasonal movement. This is often found in heavy applications of waterborne finishes where the damn fiinsh is so tough it wont break it just stretches out over the crack and turns opaque.