What type of boarding for a Cold Water Storage Cistern?

[wild nomad]

Hi there,

I am going to construct a support platform for a 50 Gallon cold water storage system. I have a good strong support base consisting of a lattice of treated joist timbers. I was wondering on what sort of boarding to use for the cistern to sit on. I was told that a good boarding to put over this would be 21mm P5 Moisture resistant T&G chipboard.

I was just wanting to hear a few suggestions from other people before I go through with it. Anyone have any ideas/agreements/disagreements with the Tongue and groove moisture resistant chipboard theme?

Thanks in advance

 

[kay-jay]

I prefer marine ply to chipboard any day.

 

[Alex Pelton]

marine ply everytime. never chipboard even waterproof

 

[townfanjon]

Marine plys great but a bit dear and can be hard to get hold of , any ply over about 20 ish mm would do .
defo not sterling board, i saw one last week in a loft and pre warned the customer

 

[lame plumber]

never use chipboard as it falls apart when wet, marine ply is expensive as it works, and meets regs reqs

 

[kay-jay]

Its all green chipboard in new builds. Ive seen lots of it bloat with water even though its treated. I would never use it.

 

[dm65]

50 gal is over 200kg - I would beef up on the joists by running 4x2across as many joists as possible and floorboard over that

 

[wetdrip]

Remember to apply a few coats of varnish to the board, including ends...waterproofed.
Much like you'd do prior to fitting a sink into a wooden worktop.

 

[Masood]

As said above. 18mm marine ply. At an absolute pinch WBP, but regs require marine ply for unvented so I just use that for cold tanks as well. Make sure it extends at least 150mm bigger than the tank in all directions.

 

[wild nomad]

As said above. 18mm marine ply. At an absolute pinch WBP, but regs require marine ply for unvented so I just use that for cold tanks as well. Make sure it extends at least 150mm bigger than the tank in all directions.

Thanks for the advice. Would you treat the ply with varnish or some sort of wood preserve or is it already treated sufficiently?

 

[kay-jay]

Its fine as is.

 

[Best]

If you did use any type of chipboard, you could always fit a sheet of heavy polythene (damp proof membrane) over the chipboard.
Plywood is strong but still requires well supported.
One problem particularily with plywood is woodbeatle absolutely love it & can chew holes right through the plastic tank base & the tank will leak. :smile: I have seen this happening.
Timber would need treated, especially in older houses