For example if I am trying to create walls at every 1 and nothing at 0, is it possible to make a nested loop that would do this? Or would it be overly complicated because of the grid system in threejs?
let wallArr = [
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 0, 0, 0, 0, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
];
This can be done in a similar way as in this examples.
See
See also
So that is just a library I can add in that will do it for me? I was wondering if there was a simple way of doing it without using another library
THREEg is a kind of library.
But the first three examples do not use a library!
You can look at the code and take things over according to your needs. 
But you can also look into THREEg and take over things.
Look for this post Circular control used for walkable areas control
The walls and some other things are created only from arrays. Is still in work.
This is what an example of a showroom created from data currently looks like.
Not sure what you are referring to but three.js does not have a “grid system”. Meaning you have to implement by yourself how your grid definition (represented as an array) is parsed into a grid expressed in world units.