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Waterlogging in basement

Hello,
So I recently moved house, and I'm setting up my workshop in the basement, but there is a bit of a water problem. The water table in the area is high, and the basement is about halfway below the surface of the ground, so whenever it rains a lot, the place turns into an indoor wading pool. The water seems to have even come almost a foot up, judging by the stains on the walls.
The plumbing here was done a bit poorly, A sump was dug right under the room, and ground water leaks into it and into the room through the trapdoor, flooding it. In order to rectify this, the owners decided to make another sump, and have a small motor pump water out of that sump into a gutter outside. So if the first groundwater sump overflows, then the water drains into the second sump, from where it is pumped outside into a gutter.
I'm not certain how effective the second sump system is, since it was built after the foot high flooding, and I haven't seen it at work.
Is there any system I can build to help contain and prevent the flooding? and any methods of waterproofing my storage cabinets and drawers? I can't do any permanent or major modifications to the room, as this is only a temporary arrangement.

Thank you for taking the time,

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gmoon1 year ago

My in-laws live very near a reservoir, and a high water-table is the norm. They have three sumps, and a pump in each. All the sumps are tied together with pipes, so the pumps can work together once the water reaches a certain level, below the floor. They also have a backup generator to run the pumps if the power fails.

I've seen water on the basement floor, but it's never flooded.

Even so, it's not unusual for the pumps to burn out from over-use (twice in the last 5-6 years).

My questions would be:

--are the sumps all on the same level? If so, why hasn't the pump in the second sump worked?

--Do you know how to check pump operation? It's generally a simple float switch--it's location depends on the pump type (Pedestal and submersible are two types they use). Lift the rod attached to the Pedestal type float, and the pump should activate. On a submersible pump, the float is usually a bulb that hangs loose; lift that up to test.

--is the basement above the level where the water drains? You don't mention a pump in the first sump--should it drain out naturally due to the terrain?

I should note that one factor that has contributed greatly to a pump failure is a clogged output pipe (it's not unusual for little critters like mice to fall into the sump). In any case, check to see if the outflow pipes are free of debris.

nerd12 (author)  gmoon1 year ago

The sumps are all on the same level, its just that they haven't added any pipes between the sumps, so sump 1 overflows, then the water flows down into a drain into sump 2, from where its pumped into the gutter. Why they couldn't just have the pump empty sump 1, I just don't know... I'll try to have them fix that.

I have seen a similar system here.
Was in a winery though and the cellar building was built during our 10 year drought.
Now with more rain they had to add sumps as well.
But their system is "computer controlled" - a tiny box, I would say arduino or similar tech).
Each section would be similar to what you have in size I guess.
The sump has 3 pumps.
First is in deeper, well like hole and pumps out more or less on a constant base, speed is controlled by how fast the water level rises.
Second pump is on the bottom of the sump and kicks in once there is a certain water level present, it stops when the water is back to normal.
The last pump is about half way up the sump and the biggest of the lot.
If the sensors detect the water level still rises about this pumps level it will start too until the water level is low enough.

I have seen the system in action after we had a lot of rain and it looked like the fire brigade is having training day LOL

gmoon nerd121 year ago

That's a good place to start. I hope the drainage system they currently have is sufficient. With that amount of water, it may not be. Two pumps would be better.

Look at the "check valve" too. It's a valve on the outflow that prevents water from flowing backwards (through the pump) into the sump. We've had those fail, also.

Might be a stupid question but what drives a person to buy a house that is constantly under water?
Don't get me wrong, no offence here, just curious as I fail to see the benefit compared to a dry house.

nerd12 (author)  Downunder35m1 year ago

The house is in a good area, and they didn't know the water table was high until it was too late. They sunk the sumps after construction, and that was when the water started flooding.

Ah, makes sense now.
Same problem with a lot of properties down here too.
Council sells former swamp or landfill areas to a developer.
Developer "trusts" the council that all is good and start building a new estate.
Once the new owners realise potential or actual problems they are lost.
After running in circles for years most decide to bite the bullet and cut the court costs.

Kiteman1 year ago

A bigger sump pump in the first hole?

If the house was built in the UK, It would have had a damp proof course added - basically a waterproof membrane to stop water penetration. I believe it is possible to get these fitted to existing properties - it will effectively consist of removing any plaster, lining the whole basement with a single waterproof membrane (or several pieces glued/welded together), and then plastering back over it.

However, the details vary considerably, depending on the way the house was built, the local hydrology/geology, and local building codes. Your best bet is to get two or three of professionals in on different days, show them the problem and ask for advice.

Depending what they suggest, you may be able to do the work yourself (in which case, take photos and write an instructable!), or you might have to pay for one of them to do the work.

(This is all assuming you own the house - if you rent, you should be able to get the landlord to do the work. Actually, even if you own the house, if nobody told you about the problem during the buying process, you may have a case for getting the vendor or surveyor to pay for the work. Again, this depends on your local regulations - in the UK, vendors and surveyors have a legal obligation to highlight problems like this.)

Proper drainage on the outside the the only real solution.
Everything else will never be able to keep the room dry.