Holes cut through hardwood floors

[Mike D.]

Hey bp

I just closed on my first property today. I went over to the house and started ripping up the old carpets. Under the carpets were two layers of stick and peel vinyl tiles on a subfloor. Some came up easier than others. After a few tiles, I realized through a crack in the subfloor, that there is hardwood underneath the subfloor. First off all, how much damage will have been caused by nailing the subfloor to the hardwood? Would you pull up the subfloor to see the condition of the hardwood? I'm thinking that they must have been in bad shape for them to cover them up. It might be cheaper to go over the subfloor with the laminate I was planning on using.

I also noticed they covered up what appear to be vents, cut through the hardwood into the crawlspace. Has anyone seen that or know why it's done?