Underground Water Storage Tank / Reservoir

[AllyD]

Hi we are considering purchasing an 1850's farmhouse which needs a lot of work doing to it, however, we have just discovered that the property has an underground water storage tank, no longer in use, under the porch/hallway.
Has anyone else got one of these and had any problems with them? The house suffers with damp - just concerned that this may be contributing to the damp as well as the dodgy external rendering. Do you think this is likely?
We have no way of getting to it other than digging up the entire floor, but we don't know how big it is or whether the drains to it have been blocked off - we presume so, as the owner claims that he had no problem with it - although he didn't tell us about the tank......so we don't know how true this is.

thanks in advance.

 

[LadyArowana]

I know there is at least one person who posts here regularly that has one, but theirs is still in use, so at least it's being useful!

 

[JoceAndChris]

Hello Ally and welcome to the forum.

That one person who has an underground rainwater tank is me. Such structures were de rigeur for properties like ours as far as I can make out, in fact my garden is full of old, brick built underground drainage and soakaways, and our well in the scullery, - most of which cause me no problems whatsoever.

My rainwater tank does cause me problems as we aren't on mains and so all the roof run-off is collected inside it, from which it is pumped to a tank in the attic. The trouble is that as an old, brick-built structure I'm pretty certain it's seeping continuous little streams, which is making my basement section rather damp. We will, eventually, solve this, by installing a new, metal, tank elsewhere and re-routing the pipes and gutters to fill this.

If you are on mains this must have happened already with your gutters and drainpipes. It's impossible for me to say whether or not all your drains have been blocked off properly though, or whether or not there's any water in your old tank.

Where is the damp in the property and how does it look? There are so many kinds of damp.

If I'd fallen in love with the property I wouldn't let this put me off too much - I'd be more concerned about the dodgy external rendering, which costs a fortune to fix. Good luck and keep us posted!

 

[AMc]

Our house dating from before 1850 but also extended around then had an system of rainwater storage and a well. There was a dome shaped brick tank fed from one downpipe that was connected to a second, larger & later tank lined fed from a newer downpipe when the house was extended sometime in the 19C. The supply for both of these had been diverted in the 1990's at the gutter level into an external soakaway. They were inside a large vinery (for growing grapes on an agricultural scale) and the tanks were presumably there to water the vines. The well had a pump feed into the kitchen so would have been used for drinking and washing.

Though there was still water in both tanks it was fresh they weren't causing any damp problems. Both were dug out when we excavated the floors when we converted this for living space so they're now gone.
When originally constructed there was an overflow which would have prevented them from flooding out onto the floor.

I would be surprised if your tank didn't have an overflow and I would expect more than damp if the inlets were still functioning and the overflow wasn't at least partially working. The only way you'll know for sure is going to be to break into it and take a look. If it is still connected to the rainwater downpipes you might be able to get a drain company to do a CCTV survey and see what's there, but I'm not sure how useful it would be.

 

[AllyD]

Thanks to everyone for your responses.

Yes the property does have water mains.

The damp is mainly on all of the external walls of the property, so that's why we presumed it was only the rendering that was the problem. There is also some damp patches on the upstairs ceilings, so we presume the roof has let in some water as the slates are not looking good. Not sure about the rafters though!

We heard about the underground tank from a third party who used to know the owner. He had said that the owner had once complained about there being fungi growing on the lounge carpet and presumed it was the tank. The owner denies this and has said that he has never had a problem and that the tank is not under the lounge. We won't know the extent of any problems with the tank until after purchasing it as we can't dig up the floor as the manhole in the hall has been covered up with tiles!! We've know idea where the drains are coming from and wouldn't know how to find this out if we can't gain access to it other than digging the floors up.

The property also has some earth floors apparently - what does this mean exactly and are they a concern?

We don't want to end up with a money pit so we have a surveyor doing a pre-purchase report on the property tomorrow to see how much everything will cost and to see if he can spot any other problems. There are other interested parties too, so we may lose out anyway!

Thanks so much in advance for everyones very informative advice....

 

[Moo]

Don't worry about earth floors. As long as you don't seal them with something unbreathable they shouldn't be any problem.
We have earth floors in our hall, passage and breakfast room (the hall and passage are stone flagged, and the breakfast room has pamments) and since we removed the cement and sweaty plastic underlay from them they've been dry as a bone.