Hello family,

 

What do you all feel/believe or think about UFH pipe clips that go on top of the insulation boards VCL, essentially piercing them? 
Any one with an experience of it going good or bad? 
I am confused between placing the insulation boards on top and cover with screed, or bottom and cover with concrete. 

They effectively self-seal themselves so are fine to pierce your VCL. Don't over think it

I'm confused about your last sentence about being confused. Whatever you do, you want your insulation below your UFH pipes, never on top. The insulation is there, partly, to prevent the heat from those pipes escaping, downwards, out of the house through your sub base. 

Couple of different things being confused here.

 

Your DPM will or should be below the insulation, so if you have a suitable depth of insulation 150mm of PIR or more it will not be pierced. The plastic membrane between the insulation and the screed, where you are attaching the UFH pipes, is there for sepereration of the insulation and screed. It stops a chemical reaction between the aluminium and cement in the screed.

2 hours ago, jayc89 said:

They effectively self-seal themselves so are fine to pierce your VCL. Don't over think it

I'm confused about your last sentence about being confused. Whatever you do, you want your insulation below your UFH pipes, never on top. The insulation is there, partly, to prevent the heat from those pipes escaping, downwards, out of the house through your sub base. 

Yes may be self seal the VCL but they all pierce the insulation boards.

Defo insulation below UFH, just above or below concrete base?

1 hour ago, JohnMo said:

Couple of different things being confused here.

 

Your DPM will or should be below the insulation, so if you have a suitable depth of insulation 150mm of PIR or more it will not be pierced. The plastic membrane between the insulation and the screed, where you are attaching the UFH pipes, is there for sepereration of the insulation and screed. It stops a chemical reaction between the aluminium and cement in the screed.

They way I watched the guys installing on numerous videos, appears to be piercing the PIR boards to anchor the pipes tight. 

old video but showing what I mean about anchoring them in. The VCL is only few millimetres, they need a couple of cms in to fit.

Edited May 15, 20233 yr by Sophiae

Possibly need a little more information. So what is your exact floor buildup?

51 minutes ago, Sophiae said:

old video but showing what I mean about anchoring them in. The VCL is only few millimetres, they need a couple of cms in to fit.

It's not a vcl, it's just a polythene sheet that's put down to separate the insualtion from the screed. Purpose is to prevent chemical reaction between the aluminium coating and the cement. Standard ground floor build up is concrete slab - dpm - insulation - polythene - UFH pipes - screed. 

 

Many variants on the above of course, e.g. Insualted raft.

On 15/05/2023 at 18:38, JohnMo said:

Possibly need a little more information. So what is your exact floor buildup?

I haven’t done the build up yet. It’s still in the design phase. 

So to get the terminology correct you don't have vapour control layer in a floor, its a damp proof membrane.  The UFH pipes are (or should be) well above the DPM, as you would not want to puncture it.

 

You possibly need to get a design bottomed out for the floor before worrying about details of holding the UFH in place.  That will fit together more naturally once the floor is designed.