I buy linolem from Lowe's and cover my floor with 2 layers. We have a small room (12x12) and the puppies have the entire thing with an expansion gate across each of the 2 doorways. The whelping box and my sleeping couch are out of there by the time the pups are 3.5 weeks old. We have thick layers of newspapers in one corner and lots of bedding and toys in another area. We changes newspaper first thing in the morning and throughout the day. They go on the paper pretty well right from the start.

I don't think a whelping box is for pups after 3 or 4 weeks old.

At about 3 wks, I convert my 4 X 5 foot pen to a 5 X 10 foot pen I use one end for papers and the other a Kuranda bed and a blanket they take to going on the papers very quickly

also, at 7 weeks - they all start to be crate trained if I have room - 1 pup to a crate, if not 2 pups to a crate amazing how quickly they learn to hold it til AM