we used to get a bale of straw for the doghouse out back for the winter so the doggie could be warm enough. it was a big golden lab. an escape artist (his pen at night was 8ft fence) who kept trying to get back to his original home (one of my uncle's had him originally and lived across the state). then one time he got away and we never heard from him again.
yes, i'd understand his preference for a pile of sawdust over a cold cement floor any time. if you have old blankets to sew together and stuff full of fresh sawdust then he might find that ok, but the thicker pile is going to be softer on a big doggie like that. old bones and all that...