Running central heating pipes through unheated voids?

[Feltwell]

Does anyone know of any reason why I can't run central heating pipes, heavily insulated of course, in the sub-floor void underneath the suspended ground floor and also in a loft space?

Only short runs but doing so would make moving some radiators much easier, as well as hiding the pipe runs.

 

[hoppy]

Who said you can't ??

 

[MdB]

Downsides I can think of:

1) Leaks would be harder to spot.
2) If plastic, vermin could have a nibble.

 

[Jon Maine]

Downsides I can think of:

1) Leaks would be harder to spot.
2) If plastic, vermin could have a nibble.

No reason why not, insulate well & get rid of the pet mice :lol: . We have them running through a culvert from the plant room to the cellar.

 

[FamilyWiggs]

Insulation is the only thing I can think of - both in terms of not losing too much heat, and also frost protection during icy periods. Sensible to be able to access pipework, but usually not always practical.

 

[Jon Maine]

Insulation is the only thing I can think of - both in terms of not losing too much heat, and also frost protection during icy periods. Sensible to be able to access pipework, but usually not always practical.

The frost protection is not quite so critical with plastic pipes, however its not worth taking a chance.

 

[Cloudscape]

I had some pipes below floor level at my last place. They weren't insulated, but they probably warmed the void a bit. Running pipes below the floor lowers the lowest part of the system, and this might affect how/if you can drain it down completely, if you need to. As for running loops up and over (in the loft), there might be a possibility of introducing airlocks? The rads in my current house are fed from one level (rads above and below the flow and return). The two at the farthest point from the boiler are pretty much useless. I'm fairly certain this is because of air getting trapped in the pipes.

 

[Jon Maine]

I had some pipes below floor level at my last place. They weren't insulated, but they probably warmed the void a bit. Running pipes below the floor lowers the lowest part of the system, and this might affect how/if you can drain it down completely, if you need to. As for running loops up and over (in the loft), there might be a possibility of introducing airlocks? The rads in my current house are fed from one level (rads above and below the flow and return). The two at the farthest point from the boiler are pretty much useless. I'm fairly certain this is because of air getting trapped in the pipes.

Fair point, may be worth considering some venting points.

 

[Feltwell]

Thanks guys.

It would be in copper, so no problem with vermin, we've never had an issue with them anyway.

The "loft" is actually the roof space of a single-storey old scullery that sticks out of the back of the house - so pipes will be level with those that are ran above the ground floor ceiling / below first floor, so shouldn't be an airlock issue. Access to there will be via a loft hatch, once I've cut one in!

Draining the below ground floor pipes is an issue - what I thought was if I drain the system down via a ground floor radiator as usual, then if required I can have an extra drain-off point on the below floor section that simply puts that last small bit of water onto the earth underneath the house. I'm fortunate in that I have access to the sub-floor (although it's getting to be more of a squeeze these days... ) and there is enough room to crawl about down there.

Frost protection - I'd be relying on the pipe insulation plus the effect of the corrosion inhibitor in the system. Beneath the ground floor will probably stay above freezing anyway, for the loft space I can put the pipe under the loft insulation if I'm careful - as well as putting the usual foam sleeve insulation around it.