The problems with attic water tanks

By The Helpful Engineer / On / In Existing Building Issues

As I have stated in previous posts, during my work as an engineer, I have carried out many house surveys for people buying properties in Britain and Ireland. After the survey I provide a written report, called a visual structural inspection report, which lists the defects that need to be rectified. I have found that the same problems with attic water tanks and attic pipe-work crop up in every property.  Water tanks are rarely, if ever installed correctly. In fact as far as I can recall no house I have ever inspected has ever had all of the following in place:

  • A tight fitting lid on the water tank.
  • A fully insulated tank with the base exposed to a part of the attic floor which has been left un-insulated to allow the heat from the house below to keep the tank from freezing in the winter.
  • Fully lagged pipe-work, again to stop it freezing in winter causing leaks.
  • A fully insulated attic access hatch.

All of these issues are easy to fix and most homeowners would have no difficulty doing the work themselves, and yet they don’t. So if you are reading this perhaps you should check your own attic before the really cold weather sets in. I can virtually guarantee you that one of the above needs addressing. It might save your health and some of your wealth.

15 thoughts on “The problems with attic water tanks

  1. Again, I can only agree.
    I have seen a lot of freezing pipes in attics, particularly last winter. A lot of buildings had additional insulation fitted to the attics and walls in the last few years. Whilst this is fantastic in terms of reducing your energy bill, it prevents heat from rising into the attic.
    So what can be done?
    If the pipes and the tank are insulated regular movement of the water should prevent any freezing. This will happen normally in a house by turning on the taps to wash hands, have showers & baths etc. It won’t however happen in commercial buildings such as schools, offices etc. as these may not be used for 2 weeks at Christmas time. In buildings which are closed for the Christmas period it is therefore suggested to drain the tank and then leave the taps open (no water will flow). The draining can be wasteful, but if the supply to the tank is closed a couple of hours before the holiday break, most of the water will probably be used up by flushing WC’s etc. Any taps connected to mains should only be opened if the mains supply is turned off as well.
    Care must be taken to ensure that the heating system has enough water in it to allow it to function, which will prevent freezing. The hot water cylinder may also run dry and it is important to ensure that the immersion is switched off and that the heating system is not trying to heat the empty cylinder.
    Only follow this advice if you are sure that no damage will be done by turning off the water. I recommend to ask your plumber before turning off any valves to ensure that no damage is done to the system by draining the pipes.

      1. Hello Helpful Engineer…l went to stay with family for a few months. Didn’t turn off the water. Now l have had to turn off the water cos l found a leak coming from a pipe that runs from attic to the floor by the back door ( this pipe is boarded in but l heard trickling like a tap was running although when l checked all taps were off). I thought it could be because l had not used the water properly for several months so had the ingenious idea of running all taps at full blast which l quickly stopped doing when the seep under the skirting became much more than a seep. I turned off the water supply and am now terrified l have done terrible damage and as l am poor l have not called out anyone for fear l wouldn’t afford the car out charge never mind the work. My question to you helpful Engineer is…have l got a disaster on my hands?

    1. In 2010 when we returned from 1 week in uk, we heard niagra falls as we un-locked our door also lights flashing in the hall. Our pipes wernt insulated, neither was there any lid on the storage tank, and this was newyears eve

  2. On the advice of the administrator of this website I did all of the above recommendations and feel very secure now that the tank/pipes won’t freeze in the attic. I also feel great having the lid on the water tank knowing that the glass insulation and any other dust won’t enter the water any more.

  3. my water tank in attic keeps emptying after i turned of mains.
    Can u gave me any avdice wat could b problem.
    Their nothing running everything is turned off.

    1. To replace the ballcock valve, you MUST first turn off your mains supply to your attic tank. There may be a valve outside the tank, near the ballcock valve but otherwise you will have to locate the stopcock, it is often under the sink in the kitchen, and use this to turn off the water supply to the entire house. Before you remove the old ball valve, you must ensure that there is no water still coming, even when the valve is open, which is when the float (ball) is hanging down. If in doubt, get a plumber, the mains water supply to the attic tank has the potential to create a bad flood, if anything goes wrong.

  4. I am about to change my old zinc attic tank for a new plastic one. Will the 22 mm brass tank couplers, to connect my two feeds out of the bottom of the tank, need rubber washers on the inside? I have nylon ones for the outside but I thought I might need a rubber washer inside, or will nylon ones do, inside and out?

  5. I would love to get reply. I have moved in to 8 year old house I bought in Ireland and we were getting a lot of noise when flushing water in toilet or using sink. It turned out it was the tank sending sound through pipes when filling in. I have mounted air release valve at the mains entrance to tank and that helped greatly with noise BUT here comes my question, why do I need that tank at all? I don’t understand I am thinking to connect everything to main and bypass the tank completely. there would be no noise and pressure in sinks and showers should improve greatly.
    Am I running to any kind of risk by doing that? Nobody in Europe is using tanks just Ireland and UK and that boggles my mind.


  6. Hi . My attic tank after a couple of showers keeps refilling up . I know we ve been told the pressure is low is this ok . We had four showers then I noticed it

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