I want to DIY 1000 sq f of 3.8" Bruce wide (7") plank engineered wood. I have just pulled my carpet The slab is in some rooms red and in some yellow. It is likely to have been painted with something becasue there is no coler along the walls where baseboards used to be. I have done nail down solid wood installation in my prior house, but never had done glue down on slab that I plan in this house. That is why I am so paranoid about my slab. A local hardwood seller scared me by saying that there mustnt be anything on the slab before I start levelling. My plan is to level, then do liquid (paint like) vapor barrier and then the wood.

1. Does anyone know what this red or yellow staff on the slab might be (house built in early 60s)?

2. Do I need to worry about this staff? Or, shall I just paint the liquid vapor barrier on top of it?

3. I have tried to remove it with paint remover - did not work. I tried a buffer on it and it work, but to a limited exten.


4. I have read some scary phrases that glue down on slab should be done only professionally. I am an average DIY with previous nail down installation experience. Can I handle the glue down, you think (spreading glue scares me most).

Thank you very much in advance
Any advice woudl be appreciated?

You need a flooring bead blaster!!
or
A buffer, with a scrape-away attachment.