Can I add insulation in trench in old slab for new plumbing?

Yellow_Fern

I have having an old slab removed in places for insertion of a new plumbing pipe. The old slab is not insulated. When this is being done, is there anything stopping me from adding some EPS (as chunks or beads) or glass foam insulation gravel around the pipe to get a wee bit of insulation benefit? I know it is not going to make a huge difference but I have seen the thermal conductivity data on concrete and even a crude 1 cm of EPS makes a significant improvement that is worth the ten mins it would take but I don't want to damage the new laid concrete. It is being done by plumbers who are not very knowledgeable on the topic

Calahonda52

location?

Yellow_Fern

Calahonda52 wrote: »

location?

Its an old terrace building. We will cut out a trench in the slab for a four inch pipe in the back room ground floor to move a toilet. There is no random barrier or anything under the slab. I guess the slab dates from around 1970.

Calahonda52

perhaps
http://www.polytherm.ie/p/calpex-pre-insulated-pex-pipe/pcalpex
if it liable to get wet when concrete poured

GreeBo

Are you insulating the waste pipe or am I misreading it?

Yellow_Fern

GreeBo wrote: »

Are you insulating the waste pipe or am I misreading it?

I have no desire. I just want to insulate part of the the floor will be opened up. Only the pipe part of the floor will be exposed so it wont make a huge impact

GreeBo

Ah ok, I wouldnt bother in that case, you will have so much cold bridging to render the insulation pointless.

Yellow_Fern

GreeBo wrote: »

Ah ok, I wouldnt bother in that case, you will have so much cold bridging to render the insulation pointless.

I see. I hadnt considered cold bridging but yeah that would be huge.