Bruce, with a mobile home that old, be sure your roof is taken care of first to prevent any leaks. try one of the mobile home roofing systems, where they lay a "skin" over it and seal it down. It will keep your home cooler in summer and warmer in winter and stop roof rumble.Also, do not seal the "belly" of the mobile home, because you will have mildew and mold problems. there is a product to close up the "belly" of the home, which will allow it to "breathe". The crooked contractor, who did ours closed it up with OSB boards and we had to pay more to the boards removed and fixed correctly with Tyvek material. Be sure the seals around your home are solid or have them replaced. If you don"t,you will have leaks at the doors. Try to keep from using window air conditioners. They will cause leaks into your walls and you won't know there is a problem until the wall gets spongy and mildewed. Good luck to you and let us know if you need any more pointers. Our remodeling cost us a fortune, because we had a crooked and he had already "slime-balled" us befor we found out about him. We are more then glad to help steer people clear of people such as the "contractor" from hell!!!!!!!