hot and cold water services in PIR insulation

[farm boy]

About to lay some PIR insulation on my floor but I need to put some Hot and cold supply pipes to kitchen and bathroom in and across the PIR insulation (Total thickness 175mm made up of multiple layers)Thinking about cutting some grooves 50mm apart in first  layer of insulation and installing Hep2o pipe in pipe system with balance of insulation over the top but concerned the 60 degree temperature hot water pipe runs may affect the PIR insulation even if in a plastic conduit.  

Any thoughts

[markc]

33 minutes ago, farm boy said:

About to lay some PIR insulation on my floor but I need to put some Hot and cold supply pipes to kitchen and bathroom in and across the PIR insulation (Total thickness 175mm made up of multiple layers)Thinking about cutting some grooves 50mm apart in first  layer of insulation and installing Hep2o pipe in pipe system with balance of insulation over the top but concerned the 60 degree temperature hot water pipe runs may affect the PIR insulation even if in a plastic conduit.  

Any thoughts

The insulation will be fine, just keep your hot and cold runs away from each other, I have never understood why some people run them close together

[Mr Punter]

18 minutes ago, markc said:

The insulation will be fine, just keep your hot and cold runs away from each other, I have never understood why some people run them close together

 

Standard for plumbers.  They also like to leave all pipework uninsulated so you need to drain off a fair amount of tepid water before the hot or cold start flowing.

[JohnMo]

 We ran our cold water in the concrete below the insulation so the water was alway a good drinking temperature. So may be run the cold pipe at the bottom and hot in the middle

[Dunny1234]

Hi all, I’ve just done this. Plastic pipe Hot, cold, secondary return fixed to slab positioned for the kitchen island.  I also tee’d of from the cold for a connection for the fridge (ice maker). All pipe lagged. 100mm insulation will be going on top (channelled out to fit pipe work), membrane,  then ufh pipe, and then 85mm of screed. (Straight run is electrics)

 

I know some people stay no to connections that can’t be accessed, but there wasn’t really another option

Edited November 10, 2021 by Dunny1234

[JohnMo]

I would beware of joints under your concrete, should the joint fail, what do you do to fix it?  A tee and 90 above the floor and run the second pipe to you ice maker

[Roundtuit]

1 hour ago, Dunny1234 said:

I know some people stay no to connections that can’t be accessed, but there wasn’t really another option

Rather you than me, but I'm sure it's not a first. ?

If 185mm is what you've got to play with, I'd put some more insulation in and use a thinner liquid screed I think.

[farm boy]

On 10/11/2021 at 11:09, farm boy said:

About to lay some PIR insulation on my floor but I need to put some Hot and cold supply pipes to kitchen and bathroom in and across the PIR insulation (Total thickness 175mm made up of multiple layers)Thinking about cutting some grooves 50mm apart in first  layer of insulation and installing Hep2o pipe in pipe system with balance of insulation over the top but concerned the 60 degree temperature hot water pipe runs may affect the PIR insulation even if in a plastic conduit.  

Any thoughts

I was thinking about doing something like this, putting the pipes 50mm apart. Just made this example with some offcuts.

[NandM]

I'm also thinking about the same with only 70-80mm insulation to play with. @farm boy - how did you make such a neat cut out?

[TonyT]

On 10/11/2021 at 18:30, Dunny1234 said:

Hi all, I’ve just done this. Plastic pipe Hot, cold, secondary return fixed to slab positioned for the kitchen island.  I also tee’d of from the cold for a connection for the fridge (ice maker). All pipe lagged. 100mm insulation will be going on top (channelled out to fit pipe work), membrane,  then ufh pipe, and then 85mm of screed. (Straight run is electrics)

 

I know some people stay no to connections that can’t be accessed, but there wasn’t really another option

I would have had the fridge feed connected at the sink so the joint was accessible- you are just giving yourself future grief!

[JohnMo]

Thinking about it, under screed pipes they have to be installed in such a way that makes it possible to replace; hence the conduit.  If you have joint below the screed, it cannot be replaced, so will not comply with Building Regs

[farm boy]

After reading the BBA certificate (see below) for my PIR  insulation I decided not to put the plumbing pipes sandwiched in between PIR layers as it says it has to be fixed to the concrete below. I have now made some plywood ducts which sit on the first 50mm of insulation and will be stuffed with rockwool after plumbing pipes installed just to get it to the kitchen area where they can then run behind the units.

 

10 Incorporation of services
10.1 De-rating of electrical cables should be considered where installation restricts air cooling of cables; the product
must not be used in direct contact with electrical heating cables or hot water pipes. Where underfloor h eating systems
are to be used, the advice of the Certificate holder should be sought.
10.2 Where possible, electrical conduits, gas and water pipes or other services should be contained within ducts or
channels within the concrete slab of ground-bearing floors. Where this is not possible, the services may be
accommodated within the insulation, provided they are securely fixed to the concrete slab. Electric cables should be
enclosed in a suitable conduit. With hot pipes, the insulation must be cut back to maintain an air space.
Page 8 of 15
10.3 Where water pipes are installed below the insulation, they must be pre-lagged with close-fitting pipe insulation.
Pipes installed above the insulation will not require lagging, although some provision needs to be made for expa nsion
and contraction.
10.4 Where the product is installed on a floor of a suspended beam-and-block design, all services must be installed so
as not to impair the floor performance.
10.5 On overlay board floors, in situations where access to the services is desirable, a duct may be formed by
mechanically fixing to the floor, timber bearers of the same thickness as the insulation to provide support for a particle
board cover. The duct should be as narrow as possible and must not exceed 400 mm in width or the maximum particle
board spans given in PD CEN/TR 12872 : 2014 without intermediate support. Services should be suitably fixed to the
floor base and not to the insulation boards.
10.6 On suspended timber ground floors, all the services should be incorporated beneath the existing floor, above the
insulation if possible.