Also, where do I put my guinea pig?
The answer is to make
space for your guinea pig first
before anything else.
A guinea pig is a living creature and as such it takes precedence over basement junk.
A basement is often not an active part of a home, and your guinea should be in part of the home that it gets lots of the attention and better access to the love that it needs.
This site lists some examples of where to find the cubes and coroplast.
If you don't have access to those stores, the supplies can be ordered online.
The inner squares of the grids must always be 1.5" or less.
And, if those still aren't options, a cage can be built out of shelving racks.
My basement is my bedroom, study, family area, exercise, dining, laundry, and computer area. My basement has been prepared in such a way that my guinea is always at a comfortable temperature in a draft free area. Most basements that I have experienced are not comfortable, and they are not draft free. Due to the fact that I spend only 5% of my life in the upstairs of my home, (and that is usually for the bathroom shower,) the downstairs was the best option for my guinea, but only because it is the main part of my home!