Dog home is build to give shelter to your dog. Along with the shelter, it is essential that the temperature of the dog home should be maintained in any weather condition. You must have to purchase the doghouse as suggested by the vet Doctor.
I think to maintain the temperature all weather wood or plywood is an ideal choice to build your doghouse because other materials like metal or plastics are not absorbed the cold or heat. Wood is the best choice to maintain the dog home temperature safe.
It is necessary to use the material that give same condition in all weather and are able to give safety too. I believe that the wood or durable plywood is ideal for your home.