I’m bidding on a substantial renovation of a 1950’s prefab home.  The manufacture is Gunnison a division of US Steel.  Hopefully some of you will know what I am talking about.

All of the interior walls are 4′ panels that just looks like smooth plywood paneling with the seems visible.  I’m told that none of them are load bearing, but I suspect that the central wall directly under the ridge is.  There was an unusual condition in the basement where the ceiling was completely sheathed in plywood, preventing access to most mechanicals.  The sheathing appears structural which would make sense, assuming the floors were panelized.

My work will involve moving most of the plumbing in the house, so obviously I will need access to the joist bays.  Additionally, I will be moving a set or stairs, and cantilivering some joists for and angle bay/window seat arrangement. 

At this point I’m trying to determine what I will be getting into as well as if I will need professional engineering help.

I understand the original homeowner met quite a bit of resistance from the local twp. when they set out to have the house erected.  I have not seen an example of this type of house before, nor do I know if more were built in the area.

Anyone have any experience with this early example of prefab housing?

Thanks,