In most cases....YES. I'm not sure if you are doing a glue-down floor or nailed...either way, you really don't want the old vinyl flooring to serve as a vapor barrier as this could lead to mold problems (in the southern market). If you are installing a nailed floor, you want to make sure that you have 3/4" plywood subfloors...depending on the age of the house, alot of newer homes had OSB subfloors installed. The nails or staples won't hold in OSB. It's always best to get back to the subfloor before installing another floor.
thanks, that's what I was thinking also. And the house was built in 1983. Is thier an easy way of getting the glued area off of sub-floor?
Is it sheet vinyl or tile squares? You can usually use a hair dryer or heat gun to warm the tiles and gently lift them up with a metal scraper. Hyde makes a bent hand held floor scraper that it perfect for this purpose. Wear some gloves and try not to scrape the subfloor....you don't have to exert much effort typically. I try to avoid using any kind of chemicals...but that's just me. Don't forget to examine your subfloor...if the space is over a basement you should be able to see the underside of the subfloor to determine if it is plywood or OSB
It is vinyl sheet glued in 1983. We found a product online that you can buy at Lowes it's called a spyder scraper and it connects to a reciprocating saw. It works really good once you get a handle on it. First try we scraped a little of the sub floor, but after you learn to let it do all the work and not to push down on it ,the work went really fast.