Footings and Water Table Problem.

[SysMax]

I've dug a footing 1m deep from ground level for a kitchen extension but hit the water table.
Overnight the bottom of the footing has about 5-8cm of surface water coming through!
If I remove this water one day the following day water has returned.

I spoke to the building inspector today and he approved the depth of the footing and gave me suggestions on how to the solve the water problem before pouring in the concrete.

First scrape out the surface wet clay then,

1. Lay a dry mixture of sand and cement ( Dry Lean Mix?) level with the the top of water level.

2. Lay type 1 filling to level with the top of the water level.

I've had other suggestions from other people like placing a layer of rubble at the bottom or sprinkling just cement at the bottom of the trench. Also i don't intend to pour the concrete the very next day after solving the water problem if I can help it.!

Please could you advise me on which solution would be acceptable from your experiences.
Many thanks in advance.

 

[HERTS P&D]

Dig a hole at one end and slope the bottom into it, then have a sump pump empty the water out on the day of the pour.

Andy

 

[JohnD]

But you'll still have to scrape out the wet mud immediately before you start.

The drylean mix, rammed down well, helps absorb free water before your main pour, so stops mud mixing with it and weakening it.

Are you sure he said dry lean sand and cement not dry lean concrete mix?

 

[SysMax]

But you'll still have to scrape out the wet mud immediately before you start.

The drylean mix, rammed down well, helps absorb free water before your main pour, so stops mud mixing with it and weakening it.

Are you sure he said dry lean sand and cement not dry lean concrete mix?

Thanks, yes he said sand and cement! Concrete dry lean does sound better though! Yes 1st scrape the muck and any soil that may have fallen in then lay the dry lean mix. What sand/cement or concrete ratio should the mix be? Thanks

 

[cdbe]

I had the same problem (heavy rain and dense clay). I used a Vax wet and dry the morning the concrete arrived - destroyed the hoover but sucked out all the liquid and slop. The barrow boys made the first few barrows of concrete nice and stiff.

 

[SysMax]

I had the same problem (heavy rain and dense clay). I used a Vax wet and dry the morning the concrete arrived - destroyed the hoover but sucked out all the liquid and slop. The barrow boys made the first few barrows of concrete nice and stiff.

Inventive idea if you can afford it lol!!!!!! Clearing that slop is one nasty job!!!!!!

 

[jeds]

Hire a pump, dewater the trench, scrape the bottom, pour concrete. Trenches should not be dug and left open for long periods, so all this should happen in a short space of time - i.e. the same day. If you can't do the whole trench in the same day make a daywork joint and work in sections.

 

[noseall]

As per jeds, we always dig and pour as quick as possible for obvious reasons.

Hire a puddle pump and suck out the water on the day of the pour along with the slop at the bottom.

 

[cdbe]

Inventive idea if you can afford it lol!!!!!! Clearing that slop is one nasty job!!!!!!

For me it was £45 well spent.

 

[SysMax]

For me it was £45 well spent.

Yes it was worth it! Thanks

 

[SpecialK]

Pumped it out the best I could and concrete got poured. Its not moved yet.