Due to water damage I am having to replace about 1200 sq ft of flooring which was all newly installed. However, the way my floor is I'm confused on how to do this without removing the bottom subfloor. Starting from under the house (its raised 5 ft) and going up there is closed cell foam which is adhered to the 3/4" subfloor, 1/2" plywood on top of that and then 1/4" plywood underlayment and finally luxury vinyl flooring. The bottom subfloor has some damage but with laying new 1/2" plywood over it it should be stable, but I'm not sure how to lay it for the best stability. Also how do you lay it correctly where the bottom subfloor is unlevel?