Fastening to interior walls

[amgostick]

Hi all,


I need to fasten a bit more wood behind our sofa (which is in the front of our trailer) to keep the cats from going behind the sofa - one can get out on its own and the other gets behind the sofa and it is a dickens of a time to get it out).


So if I were to attach some wood to the walls - they have a sort of "rug" overtop of them - do I just drill through and use self-tapping metal screws? These would need to be about 1.5" long as I plan to use a 1" x 1" piece of wood as a crosspiece and then some plywood on top to fill in the gaps.


Thanks