The world is suffering from the creatures of fantasy and nightmares which can appear with just a few minutes of warning anywhere. It can be a single one, or millions that swarm the area. The world's infrastructure has been degrading, food and supplies are harder and harder to come by. While firearms work well against these creatures the bodies left behind attract and breed both insects and disease. It is not feasible to hold on to area's with low populations as a sudden appearance of many nightmares can wipe them out.
As construction materials are harder to come by civilians turn to the only resource they have in abundance: dead bodies. They have slowly but surely started an entire industry around the collection, transport and processing of all the bodies into as many useful things as they can.
The question: How can an abundance of dead bodies be used to create as high-grade as possible building materials. Preferably good enough to repair and maintain a modern city.
Conditions that apply:
- use of omniversal materials like sand and rock are allowed, assuming they can be combined with some part of the dead bodies.
- aside from universally available materials, 75% of the building materials has to come from the dead bodies.
- anything of the creatures can be used. Their skin, bones, remaining fecal matter or small quantities of specialist materials if you see a use. Those nightmarish giant spiders could be harvested for a small quantity of spider silk after all. Use anything and everything of the creature you can or want.
- the size of the creatures goes from dog-sized to paraceratherium-sized (https://en.m.wikipedia.org/wiki/Paraceratherium).
- the answer that provides a reasonable explanation for the most advanced building materials is the best answer, even if that answer is "build tipis out of bone and leather".
- for ease of answering the important bulk of the bodies are of similar in consistency as pigs and cows.