Running central heating pipe under new oak floor

Hi all,

I am just about to start laying oak planks on a suspended wooden floor. At the moment the central heating pipework is attached to the joists, with about 10mm from the pipework to the underside of the flooring planks on top (clipped along the joist, not running across joists). The supplier of the oak planks has told me that this is too close, and the oak planks will suffer from localised heating, leading to eventual warping. I suggested putting Kingspan insulation in the gap, but they weren't happy with that either, saying that the temperature at the underside of the planks mustn't exceed 27degC, and

10mm insulation is unlikely to be sufficient, but they can't tell me how much would be sufficient. Now I can easily lower the pipes and increase the insulation thickness, but how far should I go? Given Kinspan's insulation figures, could I work out the temperature drop in any way?

At the same time as doing this job, I am insulating between the joists with 100mm Kingspan, so it makes sense to run the pipework within the Kingspan, rather than dropping the pipework down under the joists, and lagging them separately, but will, say, 50mm of Kingspan be enough to keep the temperature down sufficiently?

Incidentally, I could try an experiment with different thickness of insulation, and measuring the temperature after running the heating for a while, but I'm fitting new radiators at the moment so can't run the system to do this experiment.

thanks,

dan.

Reply to
dwtowner
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It would be more sensible to use pipe insulation around the pipes as that will reduce the amount of heat getting into the void rather than just keep it away from the top.

You can get stuff that is 3" thick.

BTW what happens in the summer when its 30C on the floor?

Reply to
dennis

wrote

Hi Dan

Sounds like the best action would be to talk to the insulation suppliers. The statement by the floor suppliers that "10mm is not enough" implies that they have detailed knowledge of all insulation products (unlikely). As I'm sure you will know, different materials have different thermal conductivity. There may be some high spec insulation that will restrict the heat to the value required. Then it's a cost vs hassle assessment.

Phil

Reply to
TheScullster

The insulation suppliers can't answer the question either. You need to know the thermal resistance of the wood and any covering as well as the room and pipe temperature to work it out.

You have a sandwich where the top will be at ~ 21C (room) and the bottom will be at 70C (pipe). The temperature at any point between depends on the thermal resistance of the layers and their thickness.

Reply to
dennis

The very best you can do is put the pipes central to the beams. I HOPE you are drilling, not notching. Notching to the beam center seriously weakens it.

Or central to two bits of 50mm insulation.

That should be OK. These things are not hard and fast, and it isn;t heat that causes wood to warp, its having the hot bit lose moisture relative to the rest. In typical winter conditions in a warm room, the RH of the air - and wood - is already very low anyway. so its not such an issue. Curiously, its in summer when wood has more chance of warping INDOORS due to high humidity. The revere of outside wood, which gets soaked in the winter rains..

Reply to
The Natural Philosopher

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