What to do with cold water tank after insulating the attic?

[Prosper]

I've finished adding 200ml of glass wool insulation on top of existing insulation. The cold water tank is on a wooden platform (3 x floorboards) 400mm above the attic floor and there's no insulation under it. Also, there's no cover on it.
To keep the water tank on the warm side I'm thinking of running insulation from the floor and up the sides of the tank but not underneath it.
I'm looking at 3 options:

1. Get a lid for the tank. I tried Brooks and DPL and they don't have lid to suit so it's unlikely there's one out there.
2. Get a wraparound insulated lagging jacket that covers the top also.
3. Install a new water tank with lid

I'm only turning my attention to the water tank issue today so I will investigate the options thoroughly but I'm hoping some AAM'ers will have already investigated the best way to do this and so save me time.

 

[Buddyboy]

Hi Prosper,
what I did was remove the water tank altogether, and put a pumped system in , sited in the boiler house.
Anyway, back to your dilemma, What I would do is, as you are thinking, run the insulation from the floor up the sides of the tank, and leave the floor uninsulated. This should prevent any chance of freezing. I'd also use some sort of wide tying mechanism to keep the insulation in place. For the top/lid, I'd get a big piece of aeroboard or similar, and sit it on top.
There is on need to over-engineer it. The purpose is to stop it freezing, and cover it. The above would address both these, and my guess is you already have the spare insulation from doing the attic.

Well done on the progress by the way.

 

[Leo]

To keep the water tank on the warm side I'm thinking of running insulation from the floor and up the sides of the tank but not underneath it.

Build up along the sides and leave the underneath free of insulation. Rigid foam insulation works well and is easy fix in place without the compression issues you'll get with mineral wool.

For the lid, cut a sheet of ply to size and wrap over with insulation.

 

[noproblem]

Don't forget to insulate the pipes coming into the tank, just as important as the tank.

 

[Prosper]

What I would do is, as you are thinking, run the insulation from the floor up the sides of the tank, and leave the floor uninsulated. This should prevent any chance of freezing. I'd also use some sort of wide tying mechanism to keep the insulation in place. For the top/lid, I'd get a big piece of aeroboard or similar, and sit it on top.

I bought a cold water tank jacket with lid. The jacket is black plasic filled with glass wool insulation and the lid is black plastic surrounding white aeroboard. Then I used duct tape to stick strips of white aeroboard to the tank and floor thereby sealing off the undertank area. I then ran the Knauf floor insulation up all 4 sides of the water tank. I'm happy now that the uninsulated area beneath the tank is sealed off from the cold side.

Rigid foam insulation works well and is easy fix in place without the compression issues you'll get with mineral wool.

I think the lagging jacket and the use of aeroboard will counter that problem

Don't forget to insulate the pipes coming into the tank

Done.

BTW while laying the new insulation I noticed a big void through which the large wavin pipe coming from the extraction fan over the cooker in the kitchen up into the attic and out through the roof. I'm sure this facilitates the transmission of sound. I was thinking about shoving some of the insulation down into the void but then decided against it.

 

[noproblem]

H'mm! I'm more than surprised that the extraction fan from the kitchen cooker is done like that, usually put out through the wall just above the cooker with a cowel over the pipe.