Help Please. New patio flooding

[hztm2008]

Hello. Could I get some advice from professionals on here who install patios please. My friend had a new patio installed around a year ago. There was originally a concrete area that had a small drain located on the line with the grass and there was never any problems with surface water. The contractor installed a retaining wall using sleepers. raised the level of the lawn, increased the size of the concreate area and and laid paving slabs. He covered the original drain and put a long gully grill along the sleepers which appears to just run the water away to the far corner. As soon as it rains, the whole area floods as can be seen in the pictures. They asked the contractor if he could do something to put the original drain back in but he has said that he needs to install a french drainage system under the lawn and he will need to dig down 2 metres. My friends cannot understand what this would be for. It looks like the problem is rain falling on the patio area rather than rain falling on the grassed area. It looks like the water simply runs in the gully along to the side of the garden. They are thinking that they maybe need to get another contractor to lift the patio slabs and re-instate the original drain somehow? We would really appreciate any advice you could offer please. Thanks

 

[sxturbo]

Get the landscaper back round to sort it.

Was any DPM put behind the sleepers?

The way the garden is now the grass will hold water above the patio level, whereas it didn't before, this may not help the situation.

The drain obviously goes in the wrong direction, maybe the patio needs to come up and a soakaway installed then relayed

 

[Alec_t]

He covered the original drain

Why? If the gully doesn't feed into that then the water has nowhere to go easily.

 

[Notch7]

So the sloping lawn was dug down to level and the new patio created is lower than the grass.

I bet the aco drain goes nowhere....it's just for show.

The solution is to dig a hole in the lawn, possibly 2 metres deep, install a proper soak away with aquacell crates, then run pipework from aco to it.

Don't forget bottom of soakaway must be well below level of patio, not grass.

That's assuming the soil is porous - do a porosity test. No point having a soakaway in heavy clay, that's just a storage tank.

 

[sxturbo]

So the sloping lawn was dug down to level and the new patio created is lower than the grass.

I bet the aco drain goes nowhere....it's just for show.

The solution is to dig a hole in the lawn, possibly 2 metres deep, install a proper soak away with aquacell crates, then run pipework from aco to it.

Don't forget bottom of soakaway must be well below level of patio, not grass.

That's assuming the soil is porous - do a porosity test. No point having a soakaway in heavy clay, that's just a storage tank.

It's the opposite way round by looks of things, the wall of sleepers built and then filled above ground level of patio.

The patio being the lowest point is serving as the drain by looks of it.