Worrying noises from loft conversion

will move 3-5% summer to winder across the grain and > about 1% along the grain, whereas chipboard is far more stable.

Thanks for that, but would movement in a softwood structure generate the sort of sounds I'm hearing? Groaning or creaking I could understand, but the sharp cracks are very distinctive and sometimes extremely loud.

A piece of small-section timber snapping in two might produce something of the sort (though not the volume) but surely if any structural members are being that severely damaged the signs would be obvious?

I think I should find an underfloor heating specialist and get her or his thoughts.

Thanks for the thought; I'll investigate.

No, nothing of that sort that I can see.

Please pass on my thanks. I hope she's moved to mow with increased energy.

Apologies for the wayward formatting in my replies; I'm not used to Thunderbird and suspect I've set something up incorrectly.

Yes.

They are.

Well what tends to happen is if tow pieces are nailed together it creaks. If they are well screwed together, you get a sharp crack.

I think you should live with it., I had such in the very hot summer,. There seemed to have been some movement, but its over now.

think you should live with it. I had such in the very hot summer...> There seemed to have been some movement, but it's over now.

Thanks. It's not an easy thing to live with, even though I'm used to it by now, but I'll consider giving it a go.

You can get snapping noises when two items under friction slip past each other. Friction makes movement limited, so stresses build up (the material compresses) until suddenly the energy is released as the pieces slip abruptly. That's the same idea as an earthquake.

For example, imagine your wooden UFH board and the substrate board (chipboard?) are sandwiched together. Your UFH board gets warm and wants to expand. The chipboard is cold and doesn't. The UFH wants to stretch but can't, so it just compresses itself. Eventually the expansion gets too much, it can't compress any further and it just has to move. The movement is abrupt and there's a good chunk of energy released, which is why it's a short loud noise.

I would expect UFH installers to fix the UFH with room to account for expansion (so the floor isn't bending), but perhaps if fixed too tightly you could get expansion noises. If it was looser the UFH board could move freely without compressing itself, and so without noise.

Theo

While I wouldn't disagree with any of what's been said before about timbers moving, I have a radiant heater in the bathroom, one of those with a long silica tube with a heater coil down the inside. It makes extremely loud and alarming clicking noises when the metal casing contracts as it cools. The casing seems to act like a sounding board and amplify the sound. I suppose what I'm saying is not to ignore other possibilities, especially something metallic.

those> with a long silica tube with a heater coil down the inside. It makes> extremely loud and alarming clicking noises when the metal casing> contracts as it cools. The casing seems to act like a sounding board> and amplify the sound. I suppose what I'm saying is not to ignore> other possibilities, especially something metallic. Thanks for that. I suppose the only way to really get an idea of what's going on is to lift the carpet and at least an area of the chipboard to expose the UFH pipes, but even that might not actually tell me anything.

Does it actually reach 24°C and cut the heating off, or is that what its set for, but never really achieves it?

Sorry, I've only just seen your question. The temperature does indeed reach 24C at which point the boiler switches off.