We just purchase a home that was built around 1960. The floor in the kitchen had a rather large hump in the middle of the floor. I was able to lower this to almost level from under the home by removing shims from the joists. Now one corner is considerably lower, about 1/2 bubble on a four foot level. The house remodeled in the 70's and all the windows and walls are square now, so I would rather not attempt jacking the floor as this would probably corrupt the square of the windows etc.
Can I use the liquid (concrete) type of floor leveling compound in order to cover with vinyl flooring? One area would be about 1 1/2" thick and the worst spot. I have thought about shimming and covering with 3/4 plywood as there are no doors or molding to interfere, but there would be a difference in floor height into one room. The underlayment is wood with old vinyl on top, If I do the self leveling liquid should I remove the vinyl? And would the weight of this compound be excessive?