hardwood floors separating

I came here to this discussion board last year when I had a metal roof installed over my home which had had wood shingles which were removed..the general contractor did not use a moisture barrier. I had condensation problems which resulted in damage to my sheetrock walls and ceiling. The floors were as they were before the job took place. The conclusion to fix this condensation problem was to remove the roof and add proper moisture barriers to stop the condensation as no amount of air circulation increase would stop it. I asked several people if adding decking would cause any problems..no I was told. So I had a roofing contractor remove the tin, add decking, tar paper and rosin paper over the tar paper. I have a long narrow house which has one small room upstairs, this was a Texas shed roof house which was remodeled completely in 1959 and had bedrooms, a kitchen and bathrooms added on one side and a 3 car garage on the other side. I have beautiful 1950's hardwood floors which were so well put down that they appeared as one solid piece. The house was exceptionally well built. The home is on pier and beam foundation. Immediately after the roof went back on we began noticing creaking when we walked on the floor. The roof was done in July and I began noticing the small separations at the outside walls about a month later..the conclusion of the contractor was the added weight of the decking was causing the problem. Then it rained when it was cold and the separations got worse.., there are cracks that a dime will fit into..so the roofer came and siliconed the flashings around the upper story.. that helped some..now I am frantic as I don't know if the separations are caused by leaks( the damage looks like moisture damage) or moisture trapped under the house( some of the flooring is changing color) or flashing or screws leaking or lack of air circulation or what. When I look in the attic the decking is screwed on the rafters only occassionally not in a pattern where all screws went into the rafters as they did on the first roofing job.I have turbine vents combined with stationary vents. There are no soffit vents. The humidity in the house rarely gets above 30%. I really need some expert opinions as I don't know what is causing the floors to separate . As the second roof job reused the panels that were in the original job should each screw be sealed on the top side so that no water is allowed to seep in, because the roofer did not do this even on the ridge where there are screws in the flats( this is an corrugated R? panel roof...flat area inbetween square ridges) . I have gotten on the roof and used silicone sealer where I could get to on the roof and at the flashings but I couldn't get to all the ridge or all the flashings. Please help. Thank you.