I had to ask the help of the twitterverse and facebook so I could write this quick post. Thanks Jenni for the correct answer and Heidi for making me spill my drink.
Yesterday while I was screwing up the last socket plate in the mud room/back hall I noticed a howling draught coming from under the garage door. Since the hardwood was installed and a new bullnose on the garage steps there has been a small gap that we hadn't noticed until now. Apart from the draught I didn't want our energy bills to increase so we needed to find a solution pronto. That's when I realised that "draught excluder" is British English and the locals had no idea what I needed. I was offered weather stripping that goes around windows and even a stuffed dachsund. It was also suggested I roll up a towel and stuff that in front of the door - great for when the door is closed, not so good when I've left in the car and there's no one to put it back in place after me!
Anyhow, after weighing up the options I had a Eureka moment and remembered I'd seen a metal strip with rubber attached in the back of the book closet and I wondered if we could screw it to the underside of the door rather than the bottom as a "draft stop". The answer was we could and, even better, it fitted perfectly. Hey presto, no more draught - in the nick of time for this morning's hail/sleet/snow/howling wind weather extravaganza. I have since learnt this strip is called a door sweep, I call it magic.