Please note - I am kind of messy. I don't make the perfect bases that Howard Lamey does, but my bases are strong and sturdy and fairly easy to do.
Here is the start of a cardboard base - 4 layers of corrugated cardboard glued together. This size is about 4" x 7". Corrugated cardboard doesn't glue together perfectly, that's why I cover it with another piece of cardboard to make it smoother and less lumpy.
Side view of the cardboard. You can see how it's a little uneven. That's why I cover it with another piece of cardboard.
Cardboard base on another piece of smooth cardboard which will form the sides and top of the little cardboard house base.
Tracing around the base
I scored the lines around the base.
Add 1/2 inches for the sides of the base. You have to measure your cardboard base and see how what the thickness is so you can add the appropriate amount. This one was just slightly over 1/2 inches actually.
Cropped around the extra cardboard to form the sides.
Cut out the corners.
Cardboard top scored and folded to fit on the corrugated cardboard base.
I use Mod Podge to glue the pieces together. When I just squirted glue on, it hurt my hands because I used so much but more importantly, it made lumps. The Mod Podge makes a smoother bond.
Center the base on the cardboard top.
When I am in a hurry, I use painter's tape to hold down the edges. If I am not in a hurry, I rotate the edges on the table to firmly affix the top to the cardboard base, then maybe use a little bit of tape. I was in a hurry tonight so I used a lot of tape.
Finished base. As I said, I was in a hurry so I got some glue on the painter's tape and made a mess. It pulled the finished layer off of the cardboard. It really doesn't matter because I will paint it with gesso and sometimes I mix sand with the gesso for more texture. But it doesn't look good when you are trying to write a tutorial.
Side view of the base. This is one of the best reasons to cover a corrugated cardboard base as it makes much straighter, even sides with better corners.
That's about it. I need to get to bed now. If you have questions, just leave a question in the comments box. I will be glad to try to answer any questions.