Thanks drew
A useful response. I was thinking a pl adhesive myself. I was going to read the label at the lumber yard tomorrow when I grab the Luan.
I'm not a fan of water based anything which you are hoping to get a long life from (except interior paint).
The stuff that was on there must have been quite thin as it looked rolled or sprayed on.
I have an idea to apply pressure. I will post a pic of it if I go through with it.
The rafters are steel as they have a bit of surface rust on them.
@ gbopp cool site. I cruised around it for a bit. Thx