Insulation under water tank

someissues

We got some renovations done a while back. As part of this we got a bigger water tank installed in the attic with aquabox etc. Its on an attic floor type of platform. I noticed they out a sheet of 20mm kingspan under the tank. Afaik, its not supposed to be insulated under the tank to prevent freezing, but I could be wrong these days. The tank itself doesn't have any lagging jacket, though that something I could fit myself.

I'm guessing it would take a bit on time for the builder to disconnect the tank etc to move and remove the sheet of insulation underneath now, but I'll insist if it's a big no no.

Is it worth pushing this to get the insulation removed?

TIA!

10-10-20

I think that the insulation installer was trying to close off the insulation envelope somewhat, but also retain some warmth under the hot-tank. Otherwise the ceilding under the tank could show signs of mould/damp due to condensation. It makes sense to me as 20mm isn't a lot of thermal resistance to be fair.

What depth of insulation was pushed between the joists elsewhere? 300mm?

someissues

Yes, 300mm. I think you're probably right, a thin enough sheet probably wont make problems as long as there is a lagging type jacket over and around the tank as well