Hi, looking on a German forum, and they are talking about Insulating a waste tank that is under the motorhome and outside in a German Winter COLD Or WORSE They have had all the usual things. Build a box around it and insulate. Someone said put salt in it,oh: To be told you need 8kg of salt for 50ltrs of waste. To stop it freezing at only -10 And so on............. But the best so far is. Put a pipe in and out of the tank, and blow warm air through it. So if you want to get making one, and copy right it....... You may never look back............... Bob.