I have an aluminum floor, if I remove a (screwed in place) access cover I can measure it, I’m pretty sure it is no more than 1/8”, and my stringers or supports are approx 12” on center with closed cell foam filling the cavity’s between them so 1/8” would be more than adequate. I re-drilled and used large head aluminum rivets to put floor back down Sent from my iPad using Lake Ontario United mobile app