UFH Upstairs

peterc14

I am putting 25mm insulation upstairs on hollowcore slabs for ufh. Just wondering would anyone recommend putting a vapour barrier over the hollowcore BEFORE the insulation is laid or is this pointless?

sydthebeat

peterc14 wrote: »

I am putting 25mm insulation upstairs on hollowcore slabs for ufh. Just wondering would anyone recommend putting a vapour barrier over the hollowcore BEFORE the insulation is laid or is this pointless?

pointless.. water vapour will move freely throughout your house..

cuculainn

Just to jump on this tread, What is the procedure for putting floor insulation on a ground floor raft?

We plan on putting 125mm insulation in. I have heard that plastic sheet needs to be put in place over the insulation. Is this correct? What is the purpose of it?

Thanks

muffler

cuculainn wrote: »

Just to jump on this tread, What is the procedure for putting floor insulation on a ground floor raft?

We plan on putting 125mm insulation in. I have heard that plastic sheet needs to be put in place over the insulation. Is this correct? What is the purpose of it?

Thanks

That is correct. The cement can chemically interact with some insulation boards and cause them to decay over a period of time so a light polythene sheet (500 gauge for example) will separate the warring parties.

muffler

muffler wrote: »

That is correct. The cement can chemically interact with some insulation boards and cause them to decay over a period of time so a light polythene sheet (500 gauge for example) will separate the warring parties.

The other reason is to stop the wet concrete diving under the insulation and lifting it.

cuculainn

Deleted User wrote: »

The other reason is to stop the wet concrete diving under the insulation and lifting it.

So if you are putting in UFH, would this go over or under the pipes?

cuculainn

cuculainn wrote: »

So if you are putting in UFH, would this go over or under the pipes?

The membrane goes over the insulation and under the concrete (& UFH pipes)