Hello, I'm after some opinions regarding underlay for my carpets on underfloor heating. I've had some mixed advice from carpet resalers and I am confused. The one chap is really pushing the left hand most underlay. He describes it as a hemp underlay with a tog value of 0.65. He suggests that rubber underlays (even the ones marketed for UFH) will perish with the heat over time and will not allow the concrete to breathe. He said the hemp would last a long time as it is more commonly used in commercial installations. The other two resalers I have spoken to both recommend rubber ones like the one in the centre (a duralay king underlay I believe or similar) which is marketed for residential UFH systems. They looked at me blankly when I asked about hemp underlay. Could anyone offer advice about what the best underlay would be please. It would be much appreciated. All of the carpet resalers have been recommended to me. Thanks very much.
I would use the one with the lowest tog rating. Good quality rubber won’t perish. Cheap rubber underlay will turn to dust over time! Sent from my iPhone using Tapatalk
I think the left hand most one looks like Envirolay 28 felt underlay... (Not sure why he called it hemp?) Which has a tog rating of 2.4. It seems a strange recommendation for an UFH system? But googling it, some sites do say it is ok as it has a open cell structure. The duralay king underlay has a tog rating of 0.8, so as you say, I would have thought would be the more obvious choice.
You one on the right isn' suitable as it' a foam underlay, I'd either go for Roma (one I have always used) or similar, keep in mind due to ufh you won' have a thick underlay regardless so that it can breath.
I think rubber ones will be better rather than hemp as there wont be much effect of heat in it too but make sure it is marked with residential UFH systems. Even it would be durable. I agree with merit that good quality rubber won't perish.
