The builder I'm working with taped floor protection directly to the floor I recently recoated. Now you can see those tape lines on the wood floor. Why did this happen, and what can I do to fix it?
Bill Cavey, technical sales professional at Loba-Wakol USA, answers:
Recently I've been getting at least one call a week with questions similar to yours where the builder or homeowner taped floor protection to the floor using tape they thought was safe. After a week or two (or even more) they pull up the tape, and although the finish doesn't peel, they can see the pattern of the tape on the finish. This can happen with both waterborne and oil-modified poly finishes, and what you're seeing is the effect from the tape's plasticizers reacting with the finish as it's off-gassing.
If the lines aren't too bad you can sometimes tape off the boards with the lines, buff out the marks and re-apply the finish. If you attempt this with a two-part waterborne finish, be extremely careful to get the right ratio of the hardener with the finish, as the ratio can affect the sheen level. Sometimes the lines can't be buffed out, in which case you are usually left resanding the entire floor.
I was on a job site where the painter was extremely angry and said he'd been taping to wood floors for 30 years and never had a problem before. I told him he was lucky to have gotten away with it for 30 years! It isn't safe to tape to wood floor finishes, no matter which tape you use, until the finish is at full cure. When taping floor protection, the pieces should be taped to each other, not the floor. It's a good idea for all wood flooring pros to put requirements about taping in their contracts to help protect themselves from any liability for potential resands.
See more on this topic: Wood Floor Finishing