this pet house is very well built - i was half expecting s rickety old thing from the descriptions i read. i purchased the small one for my cats to be able to enjoy the outdoor patio during the winter.
it is made of lightweight materials, the wood is treated with some sort of cedar smelling finish and will need to be aired out for a day or so before your pet will use it. don't buy this if you are expecting a 2x4 braces with heavy 1" plywood, you will be disappointed.
the house is very well designed. if the house wobbles at all, it is probably because the bolts along the corners of the walls need tightening. after that, dropping the floor in will stabilize the house. i used a hinge i purchased at my local hardware store for easy access to the pillows.
as for the house not being waterproof, i doubt this or any wood house would remain water tight in heavy rain or snow. but a plastic igloo type pet house and get a pad to put underneath. they are available at your local pet stores.