Replacing cold water tank - metal brackets in wall

[Green Pastures]

Hello,
Looking for some opinions about how to go about my job for the weekend. I already bought all the bits in October, then my daughter was born and I never got around to it.
Our galvanised cold water tank has a slow leak and I'm replacing it with a plastic coffin type. Initially, I thought it was supported on the beams by planks of wood and some wedges to level it up, but on closer inspection I see that underneath there is a metal bracket, pictures attached. I'm unable to see clearly but it looks like they are set into the wall and I'm wondering if possibly even counterbalanced on the other side by the neighbour's water tank.
So my first question is - how likely is that? And second question, what happens when I remove the tank?
I have bought a sheet of 18mm ply as a base which I originally planned to support using 10cm fence posts over several of the beams (at least 3) to spread the load. The reason for fence posts is to bring the beams level with the larger joist that runs perpendicular (see pics). I'm now thinking the beams won't support the weight of the new tank (plus the old tank still left to one side), and those metal brackets should be used somehow. This would be fine if the tank was the same size and shape but nowadays tanks are long and thin so it would be quite off balanced.
How should I support the new tank? Should I try to use the old bracket? Grind it off?

 

[Deleted member 267285]

I’d leave the old one in situ, and build a frame for the new one.

 

[Green Pastures]

Thanks Novice, could I ask if you would do that anyway, or is it because of the bracket? My original plan was more or less a swap in place - so that makes it a lot more complicated, I'd have to move literally all pipework and possibly even the rising main and HW expansion etc. (would be in the way if i can't build the frame over it)
If that's the route I go down then looks like it's not a job for this weekend. Or even the next few months if this lockdown continues and I can't get the timber.
Bugger!!

 

[Deleted member 267285]

Hi yes, I would do it that way, but then again it’s easier for me to alter any pipework. If you want a straight swap, you’d have to be accurate with the new one being the same size, and hope everything marries up. You’d need a new base for it anyway.

 

[Servotech]

That tank's as been leaking on/off for a very long time, so be careful with it because it's base will now be as thin as tissue paper.

You need to build a brand new flat level base out of timber for the new tank to stand on.

Flood warning...Personally I'd tie up the ball-valve and drain down the tank ASAP.

 

[Green Pastures]

100% agree with you, we need to sort asap!! Rightly or wrongly it got parked after the birth of my daughter and now we've got a bit more time I want to sort it.

OK so if the old tank stays in place I think I can get away with the rising main and the feed/expansion tank, the pipework will just have to be a bit convoluted. I can't leave the old tank exactly in situ but I can shift it out the way a few inches to make room for a pipe run to reach the new tank - which will have to go in front and off the centre line.

Should I build the base resting on the joists or spanning the roof's binders? We have a 1950s-ish trussed double roof with binders at the centre line and approx half way again out to the walls (just like this), the ceiling joists are 70X37mm/ 2.75"x 1.5" and the binders are more substantial at 50x100/ 4"x2". The binders are all bedded into the party wall. Roughly under the central binder there is a brick wall, but the new tank will be off centre from it. It's the only internal brick wall in the house that comes all the way up from ground level so hopefully load bearing. The current tank sits on a bracket at either side and the roof's central binder in the middle, might not be much weight in the middle.

 

[Harry Bloomfield]

Leaving the tank in place to counter balance your neighbours tank, it would have to be filled with water to match the weight. I cannot really believe that would be true, because it couldn't be guaranteed that either tank would always be full. The support steels might well be common to both houses, but no reason why you cannot drain, remove your tank and fit a replacement. Those brackets look as if they are quite substantial.

 

[Green Pastures]

Leaving the tank in place to counter balance your neighbours tank, it would have to be filled with water to match the weight. I cannot really believe that would be true, because it couldn't be guaranteed that either tank would always be full.

I know what you mean, seems unlikely, sadly there's no way to know if the brackets are cantilevered in the wall or not. The way there is also a wood backup made me suspicious and could have been put in under the assumption that any drain state on the other side would be temporary and the joists could take any slight weight shift for the short term and stop the tank slipping?

The support steels might well be common to both houses, but no reason why you cannot drain, remove your tank and fit a replacement. Those brackets look as if they are quite substantial.

If the new tank was the same shape I would do it. My original plan was based on the assumption all the weight was on the joists. But now I don't think there's much weight on the joists at all. With the new long-thin tank, to make use of the brackets I'd have to build a support to the same height of the brackets and keep everything level, which adds enough complication that I think it's easier to build the base in front and move the pipes, if the joists will carry it. With all of this my concern is, and maybe I'm over thinking it, why would they go to the trouble of putting the brackets there? These houses were built in the post war rush to house the displaced and the use of the brackets makes nervous about the joists capacity for load.

 

[Harry Bloomfield]

These houses were built in the post war rush to house the displaced and the use of the brackets makes nervous about the joists capacity for load.

Talk to your neighbours, see if they will let you have a look at their setups in their lofts..

 

[dal5band]

Maybe next door have already had their tank replaced !

 

[Harry Bloomfield]

Maybe next door have already had their tank replaced !

Good point and it might explain why the wood wedge was installed, to give the OP's tank more support.

 

[Madrab]

I would be really surprised if your cistern was cantilevered by your neighbour's cistern, as @Harry Bloomfield suggests, that would put too much reliance on there being 2 full cisterns in place to balance each other all the time & what would happen if your neighbour was running their services that then emptied their cistern or you did the same? That would be too high a risk and a really bad design to implement.

Is the cistern also sitting on the joists too? Cant really see from the pics.

How old is your house? I think you have a badly bodged replacement galvy cistern put in there years and years ago.

 

[Green Pastures]

Yeah been meaning to ask them when I see them, with the current situation i won't ask to go up there!

Its a 1950s end of terrace. I don't think there's much weight on the joists. It could well be a replacement as I thought it was weird having metric gate valves fitted to the output. That said, not sure it would fit through the hatch.

 

[Madrab]

No, if it's fifties then that glavy tank is in keeping with that age of house. It's not in keeping with the plumbers of that era tho, a patchy support job like that, not with that size of cistern, unless someone's been in playing about since then.