Did it a few years ago and saved a few bob. I put insulation on the interior and a little flap on the front to keep out wind and rain, but the pair of thicks just chewed it all off. They didn’t eat the timbers or roof felt off it, so it stayed relatively water proof and they both stayed in it when weather was poor, so I guess it was a success! I burned the timbers in the fire (kindling) after they both died and all we could smell was singed hair!!!
Built a slightly smaller one this time around as we only have one dog this time, he’s a big dog, but he’s also a chewing mutt so he has destroyed the roof felt and made the entrance to the kennel bigger!!!
Best timber I found (and cheapest) was pallets. Use the lats on the pallets to make the floors, walls and roofs, Make the back wall higher than the front by a few inches so you’ll have a tilted roof on it, and cover the top with felt. Also, raise the floor of the kennel off the ground by a few inches. It will prevent the timbers rotting and keep the kennel warmer. Get a good wood preservative and paint it all up and it will last you a good few years. Easily the life of the dog anyway.