Update! Shortly after the above paragraph was written, Ed put the tiniest chew mark in the corner of one of the doors - just to show he could be a chewer if he really wanted to. :)

Update Update!The boys have outgrown this cage so I built them a newer bigger cage.

• Frame built out of 2x2 pine lumber and painted
• Back and half of sides made from painted peg board
• Other half of sides and front doors made from plexiglass with 3/8" holes drilled at regular intervals (use spade bit)
• Top made from painted peg board (not fastened down)
• Shelves from painted peg board are attached to the top using 1/2" dowels. This is really sturdy, and the rats love running up and down the different levels. I originally wanted a design that was super easy to rearrange without having to get out a screwdriver or cut new dowels. But after lots of headaches with more configurable but less sturdy options, I decided that this was the best way to go.

Update: I don't recommend using pegboard for shelves. The rat urine eventually swells the wood and starts to smell bad. I thought this design would be great because I could change the shelves around easily but in the end I hardly ever rearranged them and when I rebuilt the cage I threw them all away.

• Trap door in the top that opens up onto the roof
• Plastic dog kennel tray used as the floor of the cage - easy to remove for cleaning
• Paint used: Rustoleum water based paint. Two coats makes a nice surface that is easy to clean off. I tried painting with a brush, with a roller, and with spray paint. A small paint roller was the best way to go. I didn't try to paint the insides of the holes in the peg board.

• May replace some of the shelves with a painted solid piece of wood instead of the painted pegboard. Some of the pegboard is staying wet and swelling.
• Still happy with overall cage design. It takes about 30 minutes to clean once a week. The rats still love running up and down the shelves. :)