A big muddy hole !!!!

[Forkhandles]

Hi,
Thanks for the advice on floor spec for building regulations for my basement conversion

So yesterday afternoon (Saturday) I started a 1 m2 test dig I excavated down about 600mm before my wife came home and started to complain about the mess even though it was confined to a small area of the basement.

The ground is compacted earth on top of a layer of clay

However on taking a look this morning I discovered that there was 150mm of water in the hole. Is this ground water seepage from the heavy rain and thunderstorms we had last night and can it be managed by using a Newton basedrain arround the perimeter and supporting walls.

Or is something much serious going on and should I back fill and and forget this project.

 

[^woody^]

Google " water table "

 

[Forkhandles]

Thanks Woody.....

But knowing that the level at which the ground water pressure is equal to atmospheric pressure does not really answer my questions.

 

[noseall]

Thanks Woody.....

But knowing that the level at which the ground water pressure is equal to atmospheric pressure does not really answer my questions.

.....eh?

 

[Forkhandles]

Thanks Woody.....

But knowing that the level at which the ground water pressure is equal to atmospheric pressure does not really answer my questions.

.....eh?

"The water table is the level at which the ground water pressure is equal to atmospheric pressure."

However if it helps the current level of the basement floor is about 250mm higher than the garden on to which it opens out on to and my garden does not flood.......

 

[^woody^]

Probably not, but it will tell you about how water will be at a certain level underground, and this has nothing to do with any recent rain.

This will also explain how a hole can fill with water up to a certain level, and what additional precautions may be necessary for a high water table

 

[noseall]

and what additional precautions may be necessary for a high water table

...yeah, loads of concrete.

 

[Forkhandles]

Ok..

The water level in the hole is receeding (there has been no rain here today). I don't believe it to be the water table as my understanding of geology the water table only varies on a seasonal basis.

As similar depth holes dug in the garden do not fill with water on dry days.

 

[chappers]

Whether this is watertable/ground water or runoff you are going to have to address the problem. Runoff is easier to deal with as it will be periodic and can probably be addressed with a sump/pump system. now watertable is an altogether different matter and harder to deal with requireing proper tanking(think building a swimming pool in reverese).
If the hole is now emptying it would seem that the water is probably runoff.
You really need some advise from a decent basement company who has experience of your specific area.