Said It Here

How to tell if floor marks are a manufacturing defect or installer error

Strange marks and black spots appearing on new flooring can stem from factory flaws or installation issues. Because these recurring blemishes resist hand polishing, homeowners struggle to identify the root cause before contacting their installer.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Buying boxes from different stores to check for different batches
  2. 2
    Inspecting every individual plank to check for repeating patterns
  3. 3
    Calling a technician to try hand polishing the affected areas

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/Flooring2 people · September 2026

“Floor was installed a week ago and today the light hit right that I saw one of these T-shaped marks.”source ↗

“They are all around the floor near edges of pieces.”source ↗

“Was this likely a manufacturing defect or something the installer did?”source ↗

Zenitharr · r/Flooring · 5 upvotes

“As you can see in the photo many black spots are clearly visible and they are scattered across many areas of house flooring. they suddenly started showing after 2 years of installation.”source ↗

“He used a hand polishing machine and tried for 15 minutes , still the black spots are not gone.”source ↗

PshycoNirav · r/Flooring · 4 upvotes

Where this came up

People with this problem also raised