Poblems modeling a building interior

First time poster here, although I have been lurking for a while. I’ve been using blender for a couple weeks now and I think I’ve figured out the basics however everything I’ve done up until now has been standalone models (chair, human head, etc.) and now I’m trying to model the inside of a building. The problem I keep running into is once I have walls, a ceiling, and a floor I cannot easily edit anything inside the room. Thus far I have been working without a roof, however I’m sure there is an easier way to model the interior of a structure than waiting until the finishing touches to add a roof.

So I suppose what I am asking is there a way to hide a portion of my mesh (roof/side wall) without hiding the entire thing? Maybe there is a better way to go about modeling the interior of a building all together, however every modeling tutorial I have ever found details only character heads, pillars, and single objects and thus they do not run into the problem I am currently facing.

There are different ways to manage objects.

Just to name a few:

In objects-mode:
First of all you can switch objects out of view in the outliner
Then you can use up to 20 different layers to keep your objects managable.

In edit-mode:
You can assign vertices to vertex groups.
You can hide/unhide selected vertices or defined vertex groups through the Mesh->Show/Hide menu

You can keep different unlinked meshes like a table and some chairs in one object. Then pressing the “j”-key will select all joined vertices of a selected object.

You can even model your furniture in different *.blend files and assemble them in one master- blend -file by using the “File-> Append”-menu in the “Info”- window

Thanks, you have been very helpful and I don’t think I’ll be having any more issues with this.

Try selecting part of the building with ALT+B
You can also use H in edit and object mode to hide things.