Water in Foundation Trench

Once its dug unto firm ground water won't have a lot of effect.
As the concrete is poured in the water is forced out. And concrete is full of water and loves water.

 

Dig a sump at other end of trench, continue running pump until trench is empty of water, switch off pump, pour concrete, once it's poured, water will have no affect on concrete.
You might need to run pump ocassionally as you pour.

Most bco's would be happy with this, but just check with him to make sure.

Depending on the water you might need a sump either side of footings, & move pump as you pour.

 

It may not be true water table: you'll often encounter volumes of water sat in local voids. Had an extension to do on the back of a house that was on piles: dig down and a mighty torrent came forth. Thinking of all sorts of expensive solutions but flow eventually stopped: the cellcore and shingle under the groundbeams was acting like a reservoir.

If you do have to deal with water then keeping the concrete fairly stiff will help

 

Not being funny, and just asking cos I don't know, but how do you build a sump if it is the water table? The sump will have the same level water!

Mr. HandyAndy - Really

 

The water will drain into the sump from the trench,usually it will drain quicker than it refills.

 

But the sump will already have water at the same level!

Mr. HandyAndy - Really

 

Only until it's pumped out, then unless the dig is in pure gravel the sump and excavation will re-fill with water slower than the rate at which the pump can get rid of it.

 

Ah, I guess it will. Ok.

Mr. HandyAndy - Really

 

Exactly, & once concrete is poured in that section of trench, water isn't an issue then, you move pump to next sump & repeat until all concrete is poured.

 

Hand pumps, were in the 21st century now.

Hire a Trash pump,most will handle solids up to 25mm, & will clear 1000 litres or so, of water per minute.

 

Only 10 ltrs, dig a sump & bail by hand with a bucket, cheaper.

 

You do realise you just admitted you were wrong about something

 

I will always admit when I'm wrong. But I will stick to my guns forever if I think(or know) I'm right.

And to be fair, I did start off like this:

Mr. HandyAndy - Really

 

Hi my house was built lower than the water table like your planning to do, so I'm keen to find out how you got on with your project?
I have a major problem with masses of water under my sub floor, even in dry spells. I have recently found out (after spending £1000s fitting a perimeter land drain) that my house is too low i.e my foundations are 800mm and the water table is approx 700 so water is always higher and it comes into my sub floor wherever it can! it's driving me nuts and my perimeter drain is always full even in dryer spells so dosent work without a sump pump at the end of if it?
If you went ahead with your build how have you stopped the groundwater entering the house.

 

Do you have a beam and block floor ?

 

We have a concrete base floor and then a subfloor about 700mm above it which always has quite a lot of water in it.