I am in the process of laying runs of 25 mm MDPE under the suspended
groundfloor of my 1909 house. The point is to replace a mixture of 15 mm
copper and lead which brings the rising main through the length of the
ground floor to the kitchen at the back and then to take it ( once a water
softener has been installed )

into the HW/CH system and to the bathroom.

I am using MDPE because ,
I thought it would be easier to negotiate the length and some of the
obstacles ( in practice that has proved only partially correct) #
and also I thought it a good idea to increase the bore of the current 15 mm
pipe work. ( I know that 25mm is the external dimention for MDPE.)


Must admit I had not thought of this in my planning .but , do I need to
insulate the MDPE (which of course carries cold water only )?. I presume
that I do to protect against any freezing draughts under the floor ? Dont
know why I did not think of this before.

If so , what do I need to insulate with ?. I guess most of the pupose made
pipe insulation is to fit 15mm and 22mm copper pipe work. Is there special
insulation for MDPE for use inside a house as opposed to in the ground
outside.?

Thanks for any pointers

Richard