Insulating under cold water tank?

cerebus

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom of the tank exposed to allow heat from the house  to warm the tank to prevent it from freezing was a good idea.

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

Ignore my first post, I still can't seem to edit posts...

Mistral001

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom exposed to allow heat from the house  to warm the tank to prevent it from freezing 

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

The fact that loft floor is very well insulated these days means that the loft will be practically at the same temperature as outside which could be as low as -10 or -15 degrees in some places and average well below zero over the days and nights.  Will your tea in your thermos stay warm forever?  No its temperature will reduce to the temperature surrounding it.  Same with water in even a very well insulated tank.  If the temperature in the loft is averaging below zero temperature through a long cold spell the water in the tank will eventually fall below zero and freeze. Hence it is sensible to leave the insulation off the bottom of the tank so that the heat from the room below is provided to the tank.   

ThisIsWeird

cerebus said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom of the tank exposed to allow heat from the house  to warm the tank to prevent it from freezing was a good idea.

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

Ignore my first post, I still can't seem to edit posts...

Even if the 'cog wheel' icon has disappeared, try floating the cursor arrow in the top-right corner of your post, and the 'edit' option should appear.

cerebus

ThisIsWeird said:

cerebus said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom of the tank exposed to allow heat from the house  to warm the tank to prevent it from freezing was a good idea.

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

Ignore my first post, I still can't seem to edit posts...

Even if the 'cog wheel' icon has disappeared, try floating the cursor arrow in the top-right corner of your post, and the 'edit' option should appear.

Thanks for that , can't seem to get that to work on me mobile and I would rather not clog up my phone with yet another app 

cerebus

Mistral001 said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom exposed to allow heat from the house  to warm the tank to prevent it from freezing 

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

The fact that loft floor is very well insulated these days means that the loft will be practically at the same temperature as outside which could be as low as -10 or -15 degrees in some places and average well below zero over the days and nights.  Will your tea in your thermos stay warm forever?  No its temperature will reduce to the temperature surrounding it.  Same with water in even a very well insulated tank.  If the temperature in the loft is averaging below zero temperature through a long cold spell the water in the tank will eventually fall below zero and freeze. Hence it is sensible to leave the insulation off the bottom of the tank so that the heat from the room below is provided to the tank.   

Even if there is no heat coming up from the room below because of the very well insulated loft floor?

You seem to have contradicted yourself somewhat 

CSI_Yorkshire

cerebus said:

Mistral001 said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom exposed to allow heat from the house  to warm the tank to prevent it from freezing 

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

The fact that loft floor is very well insulated these days means that the loft will be practically at the same temperature as outside which could be as low as -10 or -15 degrees in some places and average well below zero over the days and nights.  Will your tea in your thermos stay warm forever?  No its temperature will reduce to the temperature surrounding it.  Same with water in even a very well insulated tank.  If the temperature in the loft is averaging below zero temperature through a long cold spell the water in the tank will eventually fall below zero and freeze. Hence it is sensible to leave the insulation off the bottom of the tank so that the heat from the room below is provided to the tank.   

Even if there is no heat coming up from the room below because of the very well insulated loft floor?

You seem to have contradicted yourself somewhat 

Do they mean remove the insulation from the loft floor beneath the tank?

cerebus

If there is a risk of the tank freezing during very cold winters (do we still get those) then a sensible idea would be to use a background heater such as a low wattage tube heater or electric pipe warmer cables or you could install a pump to keep the water moving as keeping water moving prevents it from freezing 

cerebus

CSI_Yorkshire said:

cerebus said:

Mistral001 said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom exposed to allow heat from the house  to warm the tank to prevent it from freezing 

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

The fact that loft floor is very well insulated these days means that the loft will be practically at the same temperature as outside which could be as low as -10 or -15 degrees in some places and average well below zero over the days and nights.  Will your tea in your thermos stay warm forever?  No its temperature will reduce to the temperature surrounding it.  Same with water in even a very well insulated tank.  If the temperature in the loft is averaging below zero temperature through a long cold spell the water in the tank will eventually fall below zero and freeze. Hence it is sensible to leave the insulation off the bottom of the tank so that the heat from the room below is provided to the tank.   

Even if there is no heat coming up from the room below because of the very well insulated loft floor?

You seem to have contradicted yourself somewhat 

Do they mean remove the insulation from the loft floor beneath the tank?

Possibly but in the OPs case the tank is not sat on the floor and I'm assuming here is closer to the roof than the floor to get max pressure, would removing the insulation help given the air gap or would it simply give a way for the heat to escape from the room below?

Section62

cerebus said:

CSI_Yorkshire said:

cerebus said:

Mistral001 said:

cerebus said:

In the old days with little to no insulation on the loft floor keeping the bottom exposed to allow heat from the house  to warm the tank to prevent it from freezing 

Nowadays with highly insulated loft floors the norm , the situation has changed somewhat 

The fact that loft floor is very well insulated these days means that the loft will be practically at the same temperature as outside which could be as low as -10 or -15 degrees in some places and average well below zero over the days and nights.  Will your tea in your thermos stay warm forever?  No its temperature will reduce to the temperature surrounding it.  Same with water in even a very well insulated tank.  If the temperature in the loft is averaging below zero temperature through a long cold spell the water in the tank will eventually fall below zero and freeze. Hence it is sensible to leave the insulation off the bottom of the tank so that the heat from the room below is provided to the tank.   

Even if there is no heat coming up from the room below because of the very well insulated loft floor?

You seem to have contradicted yourself somewhat 

Do they mean remove the insulation from the loft floor beneath the tank?

Possibly but in the OPs case the tank is not sat on the floor and I'm assuming here is closer to the roof than the floor to get max pressure, would removing the insulation help given the air gap or would it simply give a way for the heat to escape from the room below?

Personally I'd use my skills to arrange the insulation - possibly with the gold plating of some extra chipboard to box in the void between tank support platform and the ceiling below - such that as much heat as possible is directed up to the tank, and as little as possible is lost into the loft.  It should be achievable with a little ingenuity.

ThisIsWeird

Section62 said:

Personally I'd use my skills to arrange the insulation - possibly with the gold plating of some extra chipboard to box in the void between tank support platform and the ceiling below - such that as much heat as possible is directed up to the tank, and as little as possible is lost into the loft.  It should be achievable with a little ingenuity.

I'd suggested something along these lines earlier on, but simply using draped insulation to form this 'heat tube' from the loft floor, but now realise it might actually not be a good idea at all.  If some insulation is removed from the loft floor under the CWS in order to allow this bit of heat to reach the CWS, and this 'house heat' is contained - directed - to the CWS via an insulated channel which won't be thoroughly ventilated to the rest of the loft (and it would be pointless if it were), then I suspect moisture coming up from the house along with this warmth will hit what will be for the most part the coldest surface in the loft - the bottom of the CWS tank - so will condense out. And, not being ventilated away, this will likely drip on to the ceiling under the CWS.

Has anyone on here ever heard of a CWS freezing solid? No, nor me. The usual freezing culprits are the supply pipes as these are much smaller diameter and hold less water - so have less heat capacity to prevent freezing. So priority should be to insulate the pipes.

Yes, in theory an insulated CWS can and will freeze if given long enough to do so, and provided it isn't topped up, but this will take - I dunno - many weeks or even months? And that is just in theory.

Insulation doesn't make things warm, but reduces heat transfer. The rate of heat transfer depends on two things - the insulation value, and the temperature difference between the two bodies. A CWS will typically be sitting at, I dunno, around 8oC? even in deep winter time as that will be the temp of the incoming mains. A well insulted tank will remain at this temp for a heck of a long time, especially since as its temp drops, the rate of heat transfer will reduce - probably exponentially? So, when the stagnant CWS water approaches freezing, the remaining heat capacity of the water will be transferring out via the insulation at an infinitesimally small rate. It will take donkey's for the CWS water to begin freezing. And for a CWS to actually freeze solid in the UK, regardless of how long it's left unattended, would take - I suspect - effectively forever. Ie, the required constant sub-zero ambient temp over the necessary time interval would almost certainly never occur in the UK - Spring would arrive first.

Insulate your CWS, and it'll never freeze! Probably.

PapClap, I'd check the existing CWS jacket is the correct and current WaterRegs/By-Laws type. Does it, for example, have a snug snap-on lid with anti-bug properties? So, do that first. Then, if you have any further concerns (if you live in the Scottish Highlands, for example) go on to Fb Marketplace, and look for PIR 'insulation boards/sheets' in your locality - there will almost certainly be sheets and part-sheets being sold for next to now't. Use a saw or craft knife to turn this into a snug box for the CWS, simply held together using Duct tape. Add a panel under the CWS platform, and a sit-on lid, but do not remove any insulation from the loft floor, and do not make a tunnel from the floor to the tank.

I think.