There are different opinions when it comes to using pea gravel for outdoor dog kennel flooring. Some proponents feel that it is fairly easy to clean and thus quite sanitary. Others are concerned that some dogs like to chew on gravel, which can become a health hazard, especially for younger dogs and puppies; both of which are most likely to chew the pea gravel. If you do want to use pea gravel for your kennel flooring here is one way that is quite effective.
First of all you need to line your kennel walls with cinder blocks so that your dog cannot dig his way out of the kennel. Eight inch blocks are a good size to use, line the entire inside perimeter of your kennel with these.
The next step is to lay down river rocks on the flooring. This will provide excellent drainage for your kennel floor which will help make it much more sanitary. First you will want to lay down a couple of layers at least of medium sized river rock and spread it out evenly over the entire floor area. You should put down enough so that your entire floor is well covered with these larger rocks. On top of this, lay down a couple of layers of large river rocks. These rocks will be large enough to discourage your dog from digging any further should he dig through the pea gravel layer that is on top.
The final layer should be pea gravel. Lay down plenty of this, enough to cover the entire area and to provide a sufficiently thick layer over the larger river rocks. The pea gravel is quite comfortable for your dog to rest on, and the larger rocks underneath will stop your dog from digging his way further if he manages to make it through the pea gravel. Use plenty of pea gravel, enough so that all of the cracks in the river rock are totally filled in with a nice layer on top.
Once the pea gravel is down you will need to smooth it out so that it is even. If you can still see, or feel, any river rocks protruding into the pea gravel you do not have enough pea gravel down. Keep adding it until the surface is totally smooth. You should probably aim to have about a six inch layer of pea gravel on top of the rocks.
As far as daily maintenance, you will need to rake the pea gravel each day to smooth it out. If your dog has an accident in the kennel simply spray the pea gravel with a mixture of bleach and water and rake it through thoroughly. The beauty of this type of dog kennel flooring is that it is naturally self draining and as such will help your kennel stay free from odors and clean.