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.

wrote in message
...
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.

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?

wrote

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.

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

"TheScullster" wrote in message
...


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.

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.

wrote:
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.

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..