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

Jack Fate wrote:
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

You can purchase pipe insulation specially made for alkathene, you'll get it
from a plumber's merchant but it's not cheap.

Most people use the 'bandage' type insulation which appears to be made from
scrap textiles.

On 16 Mar, 19:42, "Phil L" wrote:
Jack Fate wrote:
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

You can purchase pipe insulation specially made for alkathene, you'll get it
from a plumber's merchant but it's not cheap.

Most people use the 'bandage' type insulation which appears to be made from
scrap textiles.

Where do you get this "bandage" type insulation from, what thickness
is required.
And is there a typical brand name ?
Thanks,
Simon.

sm_jamieson wrote:
On 16 Mar, 19:42, "Phil L" wrote:

Most people use the 'bandage' type insulation which appears to be
made from scrap textiles.

Where do you get this "bandage" type insulation from, what thickness
is required.
And is there a typical brand name ?
Thanks,
Simon.

I've no idea what it's called, nor how thick it's meant to be, only that
I've only ever seen it wrapped around alkathene below wooden floors, I've
even used it myself many years ago.

There are a few links that mention it:

http://www.sheffins.co.uk/products/s...0&SubCatID=125

and

http://www.wickes.co.uk/ECONOMY-LAGG...ng/invt/210456

I don't think it's very popular nowadays, with all the new foam types about,
but it can be useful especially in confined spaces where the bulkier foam
cannot be applied.