garage ceiling with rooms above

My daughter and her husband are about to purchase home that was built in 1985. Although the home is in very good condition, I have one concern - the garage ceiling (with a kitchen and dining room above) is only insulated with Tyvek placed over the roll insulation. As a former electrician I am well aware that electrical codes change (as do building codes) and that items ““grandfather”” that were NOT required when the home was built. Does anyone know “what” the code was at the time this home was built and if it required 5/8" type X dry wall, if it was even available back then. OR would anyone know where I could find a copy of the 1985 building code to try and look up the material myself OR if there is an expert on the internet that could answer my question.
I am well aware of what the present day code is, and if they purchase the home , we may very well entertain bringing this item up to code. For now, I’m just trying to learn if it was legal or not, so that they can make a decision on moving forward with the purchase.

Soldier Boy

It would help to know where the home is located to make any determination like you seek.

5/8" Type X drywall was certainly available in 1985, and IMO was a requirement for fire separation at that time. Sounds like an unfinished ceiling…Tyvek covering insulation without cover??? I assume this in the US.

the home is in Pa. Where can I find what the law was at the time…? My guess is the township inspector simply did not know, assuming the law at the time required it. I’ve seen older homes that did not have the barrier, but have no idea when the law required it…

Often many areas/cities adopt different codes at different times. Since you haven’t been specific on location, you may want to go to the local Authority Having Jurisdiction ( AHJ, Construction Code Office, etc. )in your location and inquire what codes were in effect at the time in question. Then, you can google the specific code cycle in question and look up your interest.

Keep in mind… your primary concern here is “Fire separation between the garage and living space”.

Here is a good, short, article by an excellent inspector that should help…