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water reservoir in attic

Hi all,
I'm new to this forum so hope this has not been covered before (but I doubt it!)
I have found a 22"wide x 77" long x 24" deep lead lined 'tub' under the floor in the attic of my 1885 home. It has a 1.5" pipe leading into it coming from down inside the house and hooking over the top rim of the tub.There is also a .75" pipe going out the bottom (cut off as it exits the ceiling of a 2nd floor bedroom closet next to upstairs bathroom. Looks like a joist was cut out and a lead-lined wood box constructed and inserted into the space. The lead liner is about 1-2mm thick. It has a water line on the sides so it definitely held water at some point. Can anyone explain what this was for? Maybe a summer-only gravity fed water supply for a retrofitted bathroom? I'm thinking someone could have hand pumped water up into this tub for extended use. For showering or shaving etc? Just curious if anyone has any thoughts. Thanks in advance. I have a couple of photos, but can't seem to get them accepted as attachments :confused:

Re: water reservoir in attic

Also, any advice on the best method to remove this old cistern and replace/reinforce the joists?

Re: water reservoir in attic

Sounds like an innovative way to make free hot water.

Lead is easily recycled.

Re: water reservoir in attic


I could be wrong, but given the age of the house this sounds like it could be an expansion tank reservoir for an early version of a gravity-type hot water heating system that ran by gravity (before forced hot water pumps were used in heating systems).

All hot water heating systems have a "requirement" where heated hot water always expands by approx 4% as it is heated to approx 180 degrees---the amount of expansion amounts to approx a gallon, or so, but it must have an outlet to go somewhere or it will burst a pipe or radiator, ergo the expansion reservoir or expansion tank requirement.

The attic reservoir allowed the system to expand into the attic, and any excess water would drain into the bathtub to prevent water damage to the building; a variation on this system was a vent pipe onto the roof shingles, but it left ugly stains on the roof & siding.

Modern hot water heating systems have pumps & and a bladder-filled expansion tank to accommodate the excess gallon of water.

Another possibility might have been a reservoir to catch the liquid condensate from an attic-installed air conditioning system.

Re: water reservoir in attic

Thanks von_steuben!
Your explanation makes perfect sense based on other signs of when the first hot water heating system was retrofitted into the house. I think an early expansion tank is indeed what it is. Though I cannot explain the small pipe exiting the bottom. Maybe just emergency drain.

Re: water reservoir in attic


Thanks for the response!

The small pipe ordinarily connected directly to the boiler, or to one of the highest radiators in the system---as long as the boiler & radiator & piping had a way to dispose of the extra gallon or so of expansion water generated during the heating cycle, the system was OK and wouldn't be damaged---there was also a pressure-relief safety valve on some gravity HW systems if the WP exceeded a certain value.

If it WAS for a gravity HW system, then these older systems carried much more water in them: modern system <14 gal; gravity system ~50 gal. or more; this would equate to at least 2 gal of expansion water during the heating cycle.

Another attempt at posting the photos would be appreciated; from your description in your 1st post, the "tub" sounds large enough to have held 30 or more gal. of water---depending on the size of the house & the amount of rads it had back then, I wouldn't be surprised.

Other possibilities if you happen to live in the UK or Canada, is that some houses used an attic system for hot water for the taps (also called a gravity system).

Google "Residential Hot Water Gravity System Wikipedia", and see also the site below: at the heating help site, click onto Systems, then onto Hot Water, then onto "Gravity Hot-Water Heating FAQ for an article by Dan Holohan.

It may be just as well to leave the old cistern/tub in place & fill it with insulation, if the structure seems sound & the attic joists are not compromised---- it might prove to be a handy storage bin in the future for whatever.


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